Pull core block layer updates from Jens Axboe:
"This is the main pull request for block storage for 4.15-rc1.
Nothing out of the ordinary in here, and no API changes or anything
like that. Just various new features for drivers, core changes, etc.
In particular, this pull request contains:
- A patch series from Bart, closing the whole on blk/scsi-mq queue
quescing.
- A series from Christoph, building towards hidden gendisks (for
multipath) and ability to move bio chains around.
- NVMe
- Support for native multipath for NVMe (Christoph).
- Userspace notifications for AENs (Keith).
- Command side-effects support (Keith).
- SGL support (Chaitanya Kulkarni)
- FC fixes and improvements (James Smart)
- Lots of fixes and tweaks (Various)
- bcache
- New maintainer (Michael Lyle)
- Writeback control improvements (Michael)
- Various fixes (Coly, Elena, Eric, Liang, et al)
- lightnvm updates, mostly centered around the pblk interface
(Javier, Hans, and Rakesh).
- Removal of unused bio/bvec kmap atomic interfaces (me, Christoph)
- Writeback series that fix the much discussed hundreds of millions
of sync-all units. This goes all the way, as discussed previously
(me).
- Fix for missing wakeup on writeback timer adjustments (Yafang
Shao).
- Fix laptop mode on blk-mq (me).
- {mq,name} tupple lookup for IO schedulers, allowing us to have
alias names. This means you can use 'deadline' on both !mq and on
mq (where it's called mq-deadline). (me).
- blktrace race fix, oopsing on sg load (me).
- blk-mq optimizations (me).
- Obscure waitqueue race fix for kyber (Omar).
- NBD fixes (Josef).
- Disable writeback throttling by default on bfq, like we do on cfq
(Luca Miccio).
- Series from Ming that enable us to treat flush requests on blk-mq
like any other request. This is a really nice cleanup.
- Series from Ming that improves merging on blk-mq with schedulers,
getting us closer to flipping the switch on scsi-mq again.
- BFQ updates (Paolo).
- blk-mq atomic flags memory ordering fixes (Peter Z).
- Loop cgroup support (Shaohua).
- Lots of minor fixes from lots of different folks, both for core and
driver code"
* 'for-4.15/block' of git://git.kernel.dk/linux-block: (294 commits)
nvme: fix visibility of "uuid" ns attribute
blk-mq: fixup some comment typos and lengths
ide: ide-atapi: fix compile error with defining macro DEBUG
blk-mq: improve tag waiting setup for non-shared tags
brd: remove unused brd_mutex
blk-mq: only run the hardware queue if IO is pending
block: avoid null pointer dereference on null disk
fs: guard_bio_eod() needs to consider partitions
xtensa/simdisk: fix compile error
nvme: expose subsys attribute to sysfs
nvme: create 'slaves' and 'holders' entries for hidden controllers
block: create 'slaves' and 'holders' entries for hidden gendisks
nvme: also expose the namespace identification sysfs files for mpath nodes
nvme: implement multipath access to nvme subsystems
nvme: track shared namespaces
nvme: introduce a nvme_ns_ids structure
nvme: track subsystems
block, nvme: Introduce blk_mq_req_flags_t
block, scsi: Make SCSI quiesce and resume work reliably
block: Add the QUEUE_FLAG_PREEMPT_ONLY request queue flag
...
fill_balloon doing memory allocations under balloon_lock
can cause a deadlock when leak_balloon is called from
virtballoon_oom_notify and tries to take same lock.
To fix, split page allocation and enqueue and do allocations outside the lock.
Here's a detailed analysis of the deadlock by Tetsuo Handa:
In leak_balloon(), mutex_lock(&vb->balloon_lock) is called in order to
serialize against fill_balloon(). But in fill_balloon(),
alloc_page(GFP_HIGHUSER[_MOVABLE] | __GFP_NOMEMALLOC | __GFP_NORETRY) is
called with vb->balloon_lock mutex held. Since GFP_HIGHUSER[_MOVABLE]
implies __GFP_DIRECT_RECLAIM | __GFP_IO | __GFP_FS, despite __GFP_NORETRY
is specified, this allocation attempt might indirectly depend on somebody
else's __GFP_DIRECT_RECLAIM memory allocation. And such indirect
__GFP_DIRECT_RECLAIM memory allocation might call leak_balloon() via
virtballoon_oom_notify() via blocking_notifier_call_chain() callback via
out_of_memory() when it reached __alloc_pages_may_oom() and held oom_lock
mutex. Since vb->balloon_lock mutex is already held by fill_balloon(), it
will cause OOM lockup.
Thread1 Thread2
fill_balloon()
takes a balloon_lock
balloon_page_enqueue()
alloc_page(GFP_HIGHUSER_MOVABLE)
direct reclaim (__GFP_FS context) takes a fs lock
waits for that fs lock alloc_page(GFP_NOFS)
__alloc_pages_may_oom()
takes the oom_lock
out_of_memory()
blocking_notifier_call_chain()
leak_balloon()
tries to take that balloon_lock and deadlocks
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Wang <wei.w.wang@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Pull x86 core updates from Ingo Molnar:
"Note that in this cycle most of the x86 topics interacted at a level
that caused them to be merged into tip:x86/asm - but this should be a
temporary phenomenon, hopefully we'll back to the usual patterns in
the next merge window.
The main changes in this cycle were:
Hardware enablement:
- Add support for the Intel UMIP (User Mode Instruction Prevention)
CPU feature. This is a security feature that disables certain
instructions such as SGDT, SLDT, SIDT, SMSW and STR. (Ricardo Neri)
[ Note that this is disabled by default for now, there are some
smaller enhancements in the pipeline that I'll follow up with in
the next 1-2 days, which allows this to be enabled by default.]
- Add support for the AMD SEV (Secure Encrypted Virtualization) CPU
feature, on top of SME (Secure Memory Encryption) support that was
added in v4.14. (Tom Lendacky, Brijesh Singh)
- Enable new SSE/AVX/AVX512 CPU features: AVX512_VBMI2, GFNI, VAES,
VPCLMULQDQ, AVX512_VNNI, AVX512_BITALG. (Gayatri Kammela)
Other changes:
- A big series of entry code simplifications and enhancements (Andy
Lutomirski)
- Make the ORC unwinder default on x86 and various objtool
enhancements. (Josh Poimboeuf)
- 5-level paging enhancements (Kirill A. Shutemov)
- Micro-optimize the entry code a bit (Borislav Petkov)
- Improve the handling of interdependent CPU features in the early
FPU init code (Andi Kleen)
- Build system enhancements (Changbin Du, Masahiro Yamada)
- ... plus misc enhancements, fixes and cleanups"
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (118 commits)
x86/build: Make the boot image generation less verbose
selftests/x86: Add tests for the STR and SLDT instructions
selftests/x86: Add tests for User-Mode Instruction Prevention
x86/traps: Fix up general protection faults caused by UMIP
x86/umip: Enable User-Mode Instruction Prevention at runtime
x86/umip: Force a page fault when unable to copy emulated result to user
x86/umip: Add emulation code for UMIP instructions
x86/cpufeature: Add User-Mode Instruction Prevention definitions
x86/insn-eval: Add support to resolve 16-bit address encodings
x86/insn-eval: Handle 32-bit address encodings in virtual-8086 mode
x86/insn-eval: Add wrapper function for 32 and 64-bit addresses
x86/insn-eval: Add support to resolve 32-bit address encodings
x86/insn-eval: Compute linear address in several utility functions
resource: Fix resource_size.cocci warnings
X86/KVM: Clear encryption attribute when SEV is active
X86/KVM: Decrypt shared per-cpu variables when SEV is active
percpu: Introduce DEFINE_PER_CPU_DECRYPTED
x86: Add support for changing memory encryption attribute in early boot
x86/io: Unroll string I/O when SEV is active
x86/boot: Add early boot support when running with SEV active
...
Get rid of the afs_writeback record that kAFS is using to match keys with
writes made by that key.
Instead, keep a list of keys that have a file open for writing and/or
sync'ing and iterate through those.
Signed-off-by: David Howells <dhowells@redhat.com>
Since commit:
83e3c48729 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
we allocate the mem_section array dynamically in sparse_memory_present_with_active_regions(),
but some architectures, like arm64, don't call the routine to initialize sparsemem.
Let's move the initialization into memory_present() it should cover all
architectures.
Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Fixes: 83e3c48729 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
Link: http://lkml.kernel.org/r/20171107083337.89952-1-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
That we we can also poll non blk-mq queues. Mostly needed for
the NVMe multipath code, but could also be useful elsewhere.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
One page may store a set of entries of the sis->swap_map
(swap_info_struct->swap_map) in multiple swap clusters.
If some of the entries has sis->swap_map[offset] > SWAP_MAP_MAX,
multiple pages will be used to store the set of entries of the
sis->swap_map. And the pages are linked with page->lru. This is called
swap count continuation. To access the pages which store the set of
entries of the sis->swap_map simultaneously, previously, sis->lock is
used. But to improve the scalability of __swap_duplicate(), swap
cluster lock may be used in swap_count_continued() now. This may race
with add_swap_count_continuation() which operates on a nearby swap
cluster, in which the sis->swap_map entries are stored in the same page.
The race can cause wrong swap count in practice, thus cause unfreeable
swap entries or software lockup, etc.
To fix the race, a new spin lock called cont_lock is added to struct
swap_info_struct to protect the swap count continuation page list. This
is a lock at the swap device level, so the scalability isn't very well.
But it is still much better than the original sis->lock, because it is
only acquired/released when swap count continuation is used. Which is
considered rare in practice. If it turns out that the scalability
becomes an issue for some workloads, we can split the lock into some
more fine grained locks.
Link: http://lkml.kernel.org/r/20171017081320.28133-1-ying.huang@intel.com
Fixes: 235b621767 ("mm/swap: add cluster lock")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org> [4.11+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We need to deposit pre-allocated PTE page table when a PMD migration
entry is copied in copy_huge_pmd(). Otherwise, we will leak the
pre-allocated page and cause a NULL pointer dereference later in
zap_huge_pmd().
The missing counters during PMD migration entry copy process are added
as well.
The bug report is here: https://lkml.org/lkml/2017/10/29/214
Link: http://lkml.kernel.org/r/20171030144636.4836-1-zi.yan@sent.com
Fixes: 84c3fc4e9c ("mm: thp: check pmd migration entry in common path")
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This oops:
kernel BUG at fs/hugetlbfs/inode.c:484!
RIP: remove_inode_hugepages+0x3d0/0x410
Call Trace:
hugetlbfs_setattr+0xd9/0x130
notify_change+0x292/0x410
do_truncate+0x65/0xa0
do_sys_ftruncate.constprop.3+0x11a/0x180
SyS_ftruncate+0xe/0x10
tracesys+0xd9/0xde
was caused by the lack of i_size check in hugetlb_mcopy_atomic_pte.
mmap() can still succeed beyond the end of the i_size after vmtruncate
zapped vmas in those ranges, but the faults must not succeed, and that
includes UFFDIO_COPY.
We could differentiate the retval to userland to represent a SIGBUS like
a page fault would do (vs SIGSEGV), but it doesn't seem very useful and
we'd need to pick a random retval as there's no meaningful syscall
retval that would differentiate from SIGSEGV and SIGBUS, there's just
-EFAULT.
Link: http://lkml.kernel.org/r/20171016223914.2421-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The mmap(2) syscall suffers from the ABI anti-pattern of not validating
unknown flags. However, proposals like MAP_SYNC need a mechanism to
define new behavior that is known to fail on older kernels without the
support. Define a new MAP_SHARED_VALIDATE flag pattern that is
guaranteed to fail on all legacy mmap implementations.
It is worth noting that the original proposal was for a standalone
MAP_VALIDATE flag. However, when that could not be supported by all
archs Linus observed:
I see why you *think* you want a bitmap. You think you want
a bitmap because you want to make MAP_VALIDATE be part of MAP_SYNC
etc, so that people can do
ret = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED
| MAP_SYNC, fd, 0);
and "know" that MAP_SYNC actually takes.
And I'm saying that whole wish is bogus. You're fundamentally
depending on special semantics, just make it explicit. It's already
not portable, so don't try to make it so.
Rename that MAP_VALIDATE as MAP_SHARED_VALIDATE, make it have a value
of 0x3, and make people do
ret = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED_VALIDATE
| MAP_SYNC, fd, 0);
and then the kernel side is easier too (none of that random garbage
playing games with looking at the "MAP_VALIDATE bit", but just another
case statement in that map type thing.
Boom. Done.
Similar to ->fallocate() we also want the ability to validate the
support for new flags on a per ->mmap() 'struct file_operations'
instance basis. Towards that end arrange for flags to be generically
validated against a mmap_supported_flags exported by 'struct
file_operations'. By default all existing flags are implicitly
supported, but new flags require MAP_SHARED_VALIDATE and
per-instance-opt-in.
Cc: Jan Kara <jack@suse.cz>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Suggested-by: Christoph Hellwig <hch@lst.de>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Backmerge tag 'v4.14-rc7' into drm-next
Linux 4.14-rc7
Requested by Ben Skeggs for nouveau to avoid major conflicts,
and things were getting a bit conflicty already, esp around amdgpu
reverts.
Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.
For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.
However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:
----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()
// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch
virtual patch
@ depends on patch @
expression E1, E2;
@@
- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)
@ depends on patch @
expression E;
@@
- ACCESS_ONCE(E)
+ READ_ONCE(E)
----
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't currently harmful.
However, for some features it is necessary to instrument reads and
writes separately, which is not possible with ACCESS_ONCE(). This
distinction is critical to correct operation.
It's possible to transform the bulk of kernel code using the Coccinelle
script below. However, this doesn't handle comments, leaving references
to ACCESS_ONCE() instances which have been removed. As a preparatory
step, this patch converts the mm code and comments to use
{READ,WRITE}_ONCE() consistently.
----
virtual patch
@ depends on patch @
expression E1, E2;
@@
- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)
@ depends on patch @
expression E;
@@
- ACCESS_ONCE(E)
+ READ_ONCE(E)
----
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Link: http://lkml.kernel.org/r/1508792849-3115-15-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
READ_ONCE() now has an implicit smp_read_barrier_depends() call, so it
can be used instead of lockless_dereference() without any change in
semantics.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1508840570-22169-4-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull networking fixes from David Miller:
"A little more than usual this time around. Been travelling, so that is
part of it.
Anyways, here are the highlights:
1) Deal with memcontrol races wrt. listener dismantle, from Eric
Dumazet.
2) Handle page allocation failures properly in nfp driver, from Jaku
Kicinski.
3) Fix memory leaks in macsec, from Sabrina Dubroca.
4) Fix crashes in pppol2tp_session_ioctl(), from Guillaume Nault.
5) Several fixes in bnxt_en driver, including preventing potential
NVRAM parameter corruption from Michael Chan.
6) Fix for KRACK attacks in wireless, from Johannes Berg.
7) rtnetlink event generation fixes from Xin Long.
8) Deadlock in mlxsw driver, from Ido Schimmel.
9) Disallow arithmetic operations on context pointers in bpf, from
Jakub Kicinski.
10) Missing sock_owned_by_user() check in sctp_icmp_redirect(), from
Xin Long.
11) Only TCP is supported for sockmap, make that explicit with a
check, from John Fastabend.
12) Fix IP options state races in DCCP and TCP, from Eric Dumazet.
13) Fix panic in packet_getsockopt(), also from Eric Dumazet.
14) Add missing locked in hv_sock layer, from Dexuan Cui.
15) Various aquantia bug fixes, including several statistics handling
cures. From Igor Russkikh et al.
16) Fix arithmetic overflow in devmap code, from John Fastabend.
17) Fix busted socket memory accounting when we get a fault in the tcp
zero copy paths. From Willem de Bruijn.
18) Don't leave opt->tot_len uninitialized in ipv6, from Eric Dumazet"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (106 commits)
stmmac: Don't access tx_q->dirty_tx before netif_tx_lock
ipv6: flowlabel: do not leave opt->tot_len with garbage
of_mdio: Fix broken PHY IRQ in case of probe deferral
textsearch: fix typos in library helpers
rxrpc: Don't release call mutex on error pointer
net: stmmac: Prevent infinite loop in get_rx_timestamp_status()
net: stmmac: Fix stmmac_get_rx_hwtstamp()
net: stmmac: Add missing call to dev_kfree_skb()
mlxsw: spectrum_router: Configure TIGCR on init
mlxsw: reg: Add Tunneling IPinIP General Configuration Register
net: ethtool: remove error check for legacy setting transceiver type
soreuseport: fix initialization race
net: bridge: fix returning of vlan range op errors
sock: correct sk_wmem_queued accounting on efault in tcp zerocopy
bpf: add test cases to bpf selftests to cover all access tests
bpf: fix pattern matches for direct packet access
bpf: fix off by one for range markings with L{T, E} patterns
bpf: devmap fix arithmetic overflow in bitmap_size calculation
net: aquantia: Bad udp rate on default interrupt coalescing
net: aquantia: Enable coalescing management via ethtool interface
...
Size of the mem_section[] array depends on the size of the physical address space.
In preparation for boot-time switching between paging modes on x86-64
we need to make the allocation of mem_section[] dynamic, because otherwise
we waste a lot of RAM: with CONFIG_NODE_SHIFT=10, mem_section[] size is 32kB
for 4-level paging and 2MB for 5-level paging mode.
The patch allocates the array on the first call to sparse_memory_present_with_active_regions().
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170929140821.37654-2-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Last batch of drm/i915 features for v4.15:
- transparent huge pages support (Matthew)
- uapi: I915_PARAM_HAS_SCHEDULER into a capability bitmask (Chris)
- execlists: preemption (Chris)
- scheduler: user defined priorities (Chris)
- execlists optimization (Michał)
- plenty of display fixes (Imre)
- has_ipc fix (Rodrigo)
- platform features definition refactoring (Rodrigo)
- legacy cursor update fix (Maarten)
- fix vblank waits for cursor updates (Maarten)
- reprogram dmc firmware on resume, dmc state fix (Imre)
- remove use_mmio_flip module parameter (Maarten)
- wa fixes (Oscar)
- huc/guc firmware refacoring (Sagar, Michal)
- push encoder specific code to encoder hooks (Jani)
- DP MST fixes (Dhinakaran)
- eDP power sequencing fixes (Manasi)
- selftest updates (Chris, Matthew)
- mmu notifier cpu hotplug deadlock fix (Daniel)
- more VBT parser refactoring (Jani)
- max pipe refactoring (Mika Kahola)
- rc6/rps refactoring and separation (Sagar)
- userptr lockdep fix (Chris)
- tracepoint fixes and defunct tracepoint removal (Chris)
- use rcu instead of abusing stop_machine (Daniel)
- plenty of other fixes all around (Everyone)
* tag 'drm-intel-next-2017-10-12' of git://anongit.freedesktop.org/drm/drm-intel: (145 commits)
drm/i915: Update DRIVER_DATE to 20171012
drm/i915: Simplify intel_sanitize_enable_ppgtt
drm/i915/userptr: Drop struct_mutex before cleanup
drm/i915/dp: limit sink rates based on rate
drm/i915/dp: centralize max source rate conditions more
drm/i915: Allow PCH platforms fall back to BIOS LVDS mode
drm/i915: Reuse normal state readout for LVDS/DVO fixed mode
drm/i915: Use rcu instead of stop_machine in set_wedged
drm/i915: Introduce separate status variable for RC6 and LLC ring frequency setup
drm/i915: Create generic functions to control RC6, RPS
drm/i915: Create generic function to setup LLC ring frequency table
drm/i915: Rename intel_enable_rc6 to intel_rc6_enabled
drm/i915: Name structure in dev_priv that contains RPS/RC6 state as "gt_pm"
drm/i915: Move rps.hw_lock to dev_priv and s/hw_lock/pcu_lock
drm/i915: Name i915_runtime_pm structure in dev_priv as "runtime_pm"
drm/i915: Separate RPS and RC6 handling for CHV
drm/i915: Separate RPS and RC6 handling for VLV
drm/i915: Separate RPS and RC6 handling for BDW
drm/i915: Remove superfluous IS_BDW checks and non-BDW changes from gen8_enable_rps
drm/i915: Separate RPS and RC6 handling for gen6+
...
Add an option for pcpu_alloc() to support __GFP_NOWARN flag.
Currently, we always throw a warning when size or alignment
is unsupported (and also dump stack on failed allocation
requests). The warning itself is harmless since we return
NULL anyway for any failed request, which callers are
required to handle anyway. However, it becomes harmful when
panic_on_warn is set.
The rationale for the WARN() in pcpu_alloc() is that it can
be tracked when larger than supported allocation requests are
made such that allocations limits can be tweaked if warranted.
This makes sense for in-kernel users, however, there are users
of pcpu allocator where allocation size is derived from user
space requests, e.g. when creating BPF maps. In these cases,
the requests should fail gracefully without throwing a splat.
The current work-around was to check allocation size against
the upper limit of PCPU_MIN_UNIT_SIZE from call-sites for
bailing out prior to a call to pcpu_alloc() in order to
avoid throwing the WARN(). This is bad in multiple ways since
PCPU_MIN_UNIT_SIZE is an implementation detail, and having
the checks on call-sites only complicates the code for no
good reason. Thus, lets fix it generically by supporting the
__GFP_NOWARN flag that users can then use with calling the
__alloc_percpu_gfp() helper instead.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Tejun Heo <tj@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch is the followup of the prvious patch:
[writeback: schedule periodic writeback with sysctl].
There's another issue to fix.
For example,
- When the tunable was set to one hour and is reset to one second, the
new setting will not take effect for up to one hour.
Kicking the flusher threads immediately fixes it.
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When the VMA based swap readahead was introduced, a new knob
/sys/kernel/mm/swap/vma_ra_max_order
was added as the max window of VMA swap readahead. This is to make it
possible to use different max window for VMA based readahead and
original physical readahead. But Minchan Kim pointed out that this will
cause a regression because setting page-cluster sysctl to zero cannot
disable swap readahead with the change.
To fix the regression, the page-cluster sysctl is used as the max window
of both the VMA based swap readahead and original physical swap
readahead. If more fine grained control is needed in the future, more
knobs can be added as the subordinate knobs of the page-cluster sysctl.
The vma_ra_max_order knob is deleted. Because the knob was introduced
in v4.14-rc1, and this patch is targeting being merged before v4.14
releasing, there should be no existing users of this newly added ABI.
Link: http://lkml.kernel.org/r/20171011070847.16003-1-ying.huang@intel.com
Fixes: ec560175c0 ("mm, swap: VMA based swap readahead")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reported-by: Minchan Kim <minchan@kernel.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Loading the pmd without holding the pmd_lock exposes us to races with
concurrent updaters of the page tables but, worse still, it also allows
the compiler to cache the pmd value in a register and reuse it later on,
even if we've performed a READ_ONCE in between and seen a more recent
value.
In the case of page_vma_mapped_walk, this leads to the following crash
when the pmd loaded for the initial pmd_trans_huge check is all zeroes
and a subsequent valid table entry is loaded by check_pmd. We then
proceed into map_pte, but the compiler re-uses the zero entry inside
pte_offset_map, resulting in a junk pointer being installed in
pvmw->pte:
PC is at check_pte+0x20/0x170
LR is at page_vma_mapped_walk+0x2e0/0x540
[...]
Process doio (pid: 2463, stack limit = 0xffff00000f2e8000)
Call trace:
check_pte+0x20/0x170
page_vma_mapped_walk+0x2e0/0x540
page_mkclean_one+0xac/0x278
rmap_walk_file+0xf0/0x238
rmap_walk+0x64/0xa0
page_mkclean+0x90/0xa8
clear_page_dirty_for_io+0x84/0x2a8
mpage_submit_page+0x34/0x98
mpage_process_page_bufs+0x164/0x170
mpage_prepare_extent_to_map+0x134/0x2b8
ext4_writepages+0x484/0xe30
do_writepages+0x44/0xe8
__filemap_fdatawrite_range+0xbc/0x110
file_write_and_wait_range+0x48/0xd8
ext4_sync_file+0x80/0x4b8
vfs_fsync_range+0x64/0xc0
SyS_msync+0x194/0x1e8
This patch fixes the problem by ensuring that READ_ONCE is used before
the initial checks on the pmd, and this value is subsequently used when
checking whether or not the pmd is present. pmd_check is removed and
the pmd_present check is inlined directly.
Link: http://lkml.kernel.org/r/1507222630-5839-1-git-send-email-will.deacon@arm.com
Fixes: f27176cfc3 ("mm: convert page_mkclean_one() to use page_vma_mapped_walk()")
Signed-off-by: Will Deacon <will.deacon@arm.com>
Tested-by: Yury Norov <ynorov@caviumnetworks.com>
Tested-by: Richard Ruigrok <rruigrok@codeaurora.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commits 5d17a73a2e ("vmalloc: back off when the current
task is killed") and 171012f561 ("mm: don't warn when vmalloc() fails
due to a fatal signal").
Commit 5d17a73a2e ("vmalloc: back off when the current task is
killed") made all vmalloc allocations from a signal-killed task fail.
We have seen crashes in the tty driver from this, where a killed task
exiting tries to switch back to N_TTY, fails n_tty_open because of the
vmalloc failing, and later crashes when dereferencing tty->disc_data.
Arguably, relying on a vmalloc() call to succeed in order to properly
exit a task is not the most robust way of doing things. There will be a
follow-up patch to the tty code to fall back to the N_NULL ldisc.
But the justification to make that vmalloc() call fail like this isn't
convincing, either. The patch mentions an OOM victim exhausting the
memory reserves and thus deadlocking the machine. But the OOM killer is
only one, improbable source of fatal signals. It doesn't make sense to
fail allocations preemptively with plenty of memory in most cases.
The patch doesn't mention real-life instances where vmalloc sites would
exhaust memory, which makes it sound more like a theoretical issue to
begin with. But just in case, the OOM access to memory reserves has
been restricted on the allocator side in cd04ae1e2d ("mm, oom: do not
rely on TIF_MEMDIE for memory reserves access"), which should take care
of any theoretical concerns on that front.
Revert this patch, and the follow-up that suppresses the allocation
warnings when we fail the allocations due to a signal.
Link: http://lkml.kernel.org/r/20171004185906.GB2136@cmpxchg.org
Fixes: 171012f561 ("mm: don't warn when vmalloc() fails due to a fatal signal")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alan Cox <alan@llwyncelyn.cymru>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
cma_alloc() unconditionally prints an INFO message when the CMA
allocation fails. Make this message conditional on the non-presence of
__GFP_NOWARN in gfp_mask.
This patch aims at removing INFO messages that are displayed when the
VC4 driver tries to allocate buffer objects. From the driver
perspective an allocation failure is acceptable, and the driver can
possibly do something to make following allocation succeed (like
flushing the VC4 internal cache).
Link: http://lkml.kernel.org/r/20171004125447.15195-1-boris.brezillon@free-electrons.com
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Laura Abbott <labbott@redhat.com>
Cc: Jaewon Kim <jaewon31.kim@samsung.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Eric Anholt <eric@anholt.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A non present pmd entry can appear after pmd_lock is taken in
page_vma_mapped_walk(), even if THP migration is not enabled. The
WARN_ONCE is unnecessary.
Link: http://lkml.kernel.org/r/20171003142606.12324-1-zi.yan@sent.com
Fixes: 616b837153 ("mm: thp: enable thp migration in generic path")
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Tested-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 3a321d2a3d ("mm: change the call sites of numa statistics
items") separated NUMA counters from zone counters, but the
NUMA_INTERLEAVE_HIT call site wasn't updated to use the new interface.
So alloc_page_interleave() actually increments NR_ZONE_INACTIVE_FILE
instead of NUMA_INTERLEAVE_HIT.
Fix this by using __inc_numa_state() interface to increment
NUMA_INTERLEAVE_HIT.
Link: http://lkml.kernel.org/r/20171003191003.8573-1-aryabinin@virtuozzo.com
Fixes: 3a321d2a3d ("mm: change the call sites of numa statistics items")
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Kemi Wang <kemi.wang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/madvise.c has a brief description about all MADV_ flags. Add a
description for the newly added MADV_WIPEONFORK and MADV_KEEPONFORK.
Although man page has the similar information, but it'd better to keep
the consistent with other flags.
Link: http://lkml.kernel.org/r/1506117328-88228-1-git-send-email-yang.s@alibaba-inc.com
Signed-off-by: Yang Shi <yang.s@alibaba-inc.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Index was incremented before last use and thus the second array could
dereference to an invalid address (not mentioning the fact that it did
not properly clear the entry we intended to clear).
Link: http://lkml.kernel.org/r/1506973525-16491-1-git-send-email-jglisse@redhat.com
Fixes: 8315ada7f0 ("mm/migrate: allow migrate_vma() to alloc new page on empty entry")
Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com>
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch fixes up some grammar and spelling in the information block for
huge_memory.c.
Signed-off-by: Michael DeGuzis <mdeguzis@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Instead of calling mem_cgroup_sk_alloc() from BH context,
it is better to call it from inet_csk_accept() in process context.
Not only this removes code in mem_cgroup_sk_alloc(), but it also
fixes a bug since listener might have been dismantled and css_get()
might cause a use-after-free.
Fixes: e994b2f0fb ("tcp: do not lock listener to process SYN packets")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
After disable periodic writeback by writing 0 to
dirty_writeback_centisecs, the handler wb_workfn() will not be
entered again until the dirty background limit reaches or
sync syscall is executed or no enough free memory available or
vmscan is triggered.
So the periodic writeback can't be enabled by writing a non-zero
value to dirty_writeback_centisecs.
As it can be disabled by sysctl, it should be able to enable by
sysctl as well.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We are planning to use our own tmpfs mnt in i915 in place of the
shm_mnt, such that we can control the mount options, in particular
huge=, which we require to support huge-gtt-pages. So rather than roll
our own version of __shmem_file_setup, it would be preferred if we could
just give shmem our mnt, and let it do the rest.
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171006145041.21673-2-matthew.auld@intel.com
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20171006221833.32439-1-chris@chris-wilson.co.uk
After commit b35bd0d9f8, pdflush_proc_obsolete() is no longer
used. Kill the function and declaration.
Reported-by: Rakesh Pandit <rakesh@tuxera.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Unlike the SMP case, the !SMP case does not free the memory for struct
pcpu_alloc_info allocated in setup_per_cpu_areas(). And to give it a
chance of being reused by the page allocator later, align it to a page
boundary just like its size.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Dennis Zhou <dennisszhou@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
find_{smallest|biggest}_section_pfn()s find the smallest/biggest section
and return the pfn of the section. But the functions are defined as int.
So the functions always return 0x00000000 - 0xffffffff. It means if
memory address is over 16TB, the functions does not work correctly.
To handle 64 bit value, the patch defines
find_{smallest|biggest}_section_pfn() as unsigned long.
Fixes: 815121d2b5 ("memory_hotplug: clear zone when removing the memory")
Link: http://lkml.kernel.org/r/d9d5593a-d0a4-c4be-ab08-493df59a85c6@gmail.com
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pfn_to_section_nr() and section_nr_to_pfn() are defined as macro.
pfn_to_section_nr() has no issue even if it is defined as macro. But
section_nr_to_pfn() has overflow issue if sec is defined as int.
section_nr_to_pfn() just shifts sec by PFN_SECTION_SHIFT. If sec is
defined as unsigned long, section_nr_to_pfn() returns pfn as 64 bit value.
But if sec is defined as int, section_nr_to_pfn() returns pfn as 32 bit
value.
__remove_section() calculates start_pfn using section_nr_to_pfn() and
scn_nr defined as int. So if hot-removed memory address is over 16TB,
overflow issue occurs and section_nr_to_pfn() does not calculate correct
pfn.
To make callers use proper arg, the patch changes the macros to inline
functions.
Fixes: 815121d2b5 ("memory_hotplug: clear zone when removing the memory")
Link: http://lkml.kernel.org/r/e643a387-e573-6bbf-d418-c60c8ee3d15e@gmail.com
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memmap_init_zone gets a pfn range to initialize and it can be really
large resulting in a soft lockup on non-preemptible kernels
NMI watchdog: BUG: soft lockup - CPU#31 stuck for 23s! [kworker/u642:5:1720]
[...]
task: ffff88ecd7e902c0 ti: ffff88eca4e50000 task.ti: ffff88eca4e50000
RIP: move_pfn_range_to_zone+0x185/0x1d0
[...]
Call Trace:
devm_memremap_pages+0x2c7/0x430
pmem_attach_disk+0x2fd/0x3f0 [nd_pmem]
nvdimm_bus_probe+0x64/0x110 [libnvdimm]
driver_probe_device+0x1f7/0x420
bus_for_each_drv+0x52/0x80
__device_attach+0xb0/0x130
bus_probe_device+0x87/0xa0
device_add+0x3fc/0x5f0
nd_async_device_register+0xe/0x40 [libnvdimm]
async_run_entry_fn+0x43/0x150
process_one_work+0x14e/0x410
worker_thread+0x116/0x490
kthread+0xc7/0xe0
ret_from_fork+0x3f/0x70
Fix this by adding a scheduling point once per page block.
Link: http://lkml.kernel.org/r/20170918121410.24466-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Dan Williams <dan.j.williams@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm, memory_hotplug: fix few soft lockups in memory
hotadd".
Johannes has noticed few soft lockups when adding a large nvdimm device.
All of them were caused by a long loop without any explicit cond_resched
which is a problem for !PREEMPT kernels.
The fix is quite straightforward. Just make sure that cond_resched gets
called from time to time.
This patch (of 3):
__add_pages gets a pfn range to add and there is no upper bound for a
single call. This is usually a memory block aligned size for the
regular memory hotplug - smaller sizes are usual for memory balloning
drivers, or the whole NUMA node for physical memory online. There is no
explicit scheduling point in that code path though.
This can lead to long latencies while __add_pages is executed and we
have even seen a soft lockup report during nvdimm initialization with
!PREEMPT kernel
NMI watchdog: BUG: soft lockup - CPU#11 stuck for 23s! [kworker/u641:3:832]
[...]
Workqueue: events_unbound async_run_entry_fn
task: ffff881809270f40 ti: ffff881809274000 task.ti: ffff881809274000
RIP: _raw_spin_unlock_irqrestore+0x11/0x20
RSP: 0018:ffff881809277b10 EFLAGS: 00000286
[...]
Call Trace:
sparse_add_one_section+0x13d/0x18e
__add_pages+0x10a/0x1d0
arch_add_memory+0x4a/0xc0
devm_memremap_pages+0x29d/0x430
pmem_attach_disk+0x2fd/0x3f0 [nd_pmem]
nvdimm_bus_probe+0x64/0x110 [libnvdimm]
driver_probe_device+0x1f7/0x420
bus_for_each_drv+0x52/0x80
__device_attach+0xb0/0x130
bus_probe_device+0x87/0xa0
device_add+0x3fc/0x5f0
nd_async_device_register+0xe/0x40 [libnvdimm]
async_run_entry_fn+0x43/0x150
process_one_work+0x14e/0x410
worker_thread+0x116/0x490
kthread+0xc7/0xe0
ret_from_fork+0x3f/0x70
DWARF2 unwinder stuck at ret_from_fork+0x3f/0x70
Fix this by adding cond_resched once per each memory section in the
given pfn range. Each section is constant amount of work which itself
is not too expensive but many of them will just add up.
Link: http://lkml.kernel.org/r/20170918121410.24466-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Dan Williams <dan.j.williams@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For quick per-memcg indexing, slab caches and list_lru structures
maintain linear arrays of descriptors. As the number of concurrent
memory cgroups in the system goes up, this requires large contiguous
allocations (8k cgroups = order-5, 16k cgroups = order-6 etc.) for every
existing slab cache and list_lru, which can easily fail on loaded
systems. E.g.:
mkdir: page allocation failure: order:5, mode:0x14040c0(GFP_KERNEL|__GFP_COMP), nodemask=(null)
CPU: 1 PID: 6399 Comm: mkdir Not tainted 4.13.0-mm1-00065-g720bbe532b7c-dirty #481
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014
Call Trace:
? __alloc_pages_direct_compact+0x4c/0x110
__alloc_pages_nodemask+0xf50/0x1430
alloc_pages_current+0x60/0xc0
kmalloc_order_trace+0x29/0x1b0
__kmalloc+0x1f4/0x320
memcg_update_all_list_lrus+0xca/0x2e0
mem_cgroup_css_alloc+0x612/0x670
cgroup_apply_control_enable+0x19e/0x360
cgroup_mkdir+0x322/0x490
kernfs_iop_mkdir+0x55/0x80
vfs_mkdir+0xd0/0x120
SyS_mkdirat+0x6c/0xe0
SyS_mkdir+0x14/0x20
entry_SYSCALL_64_fastpath+0x18/0xad
Mem-Info:
active_anon:2965 inactive_anon:19 isolated_anon:0
active_file:100270 inactive_file:98846 isolated_file:0
unevictable:0 dirty:0 writeback:0 unstable:0
slab_reclaimable:7328 slab_unreclaimable:16402
mapped:771 shmem:52 pagetables:278 bounce:0
free:13718 free_pcp:0 free_cma:0
This output is from an artificial reproducer, but we have repeatedly
observed order-7 failures in production in the Facebook fleet. These
systems become useless as they cannot run more jobs, even though there
is plenty of memory to allocate 128 individual pages.
Use kvmalloc and kvzalloc to fall back to vmalloc space if these arrays
prove too large for allocating them physically contiguous.
Link: http://lkml.kernel.org/r/20170918184919.20644-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
MADV_FREE clears pte dirty bit and then marks the page lazyfree (clear
SwapBacked). There is no lock to prevent the page is added to swap
cache between these two steps by page reclaim. If page reclaim finds
such page, it will simply add the page to swap cache without pageout the
page to swap because the page is marked as clean. Next time, page fault
will read data from the swap slot which doesn't have the original data,
so we have a data corruption. To fix issue, we mark the page dirty and
pageout the page.
However, we shouldn't dirty all pages which is clean and in swap cache.
swapin page is swap cache and clean too. So we only dirty page which is
added into swap cache in page reclaim, which shouldn't be swapin page.
As Minchan suggested, simply dirty the page in add_to_swap can do the
job.
Fixes: 802a3a92ad ("mm: reclaim MADV_FREE pages")
Link: http://lkml.kernel.org/r/08c84256b007bf3f63c91d94383bd9eb6fee2daa.1506446061.git.shli@fb.com
Signed-off-by: Shaohua Li <shli@fb.com>
Reported-by: Artem Savkov <asavkov@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org> [4.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
MADV_FREE clears pte dirty bit and then marks the page lazyfree (clear
SwapBacked). There is no lock to prevent the page is added to swap
cache between these two steps by page reclaim. Page reclaim could add
the page to swap cache and unmap the page. After page reclaim, the page
is added back to lru. At that time, we probably start draining per-cpu
pagevec and mark the page lazyfree. So the page could be in a state
with SwapBacked cleared and PG_swapcache set. Next time there is a
refault in the virtual address, do_swap_page can find the page from swap
cache but the page has PageSwapCache false because SwapBacked isn't set,
so do_swap_page will bail out and do nothing. The task will keep
running into fault handler.
Fixes: 802a3a92ad ("mm: reclaim MADV_FREE pages")
Link: http://lkml.kernel.org/r/6537ef3814398c0073630b03f176263bc81f0902.1506446061.git.shli@fb.com
Signed-off-by: Shaohua Li <shli@fb.com>
Reported-by: Artem Savkov <asavkov@redhat.com>
Tested-by: Artem Savkov <asavkov@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org> [4.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Eryu noticed that he could sometimes get a leftover error reported when
it shouldn't be on fsync with ext2 and non-journalled ext4.
The problem is that writeback_single_inode still uses filemap_fdatawait.
That picks up a previously set AS_EIO flag, which would ordinarily have
been cleared before.
Since we're mostly using this function as a replacement for
filemap_check_errors, have filemap_check_and_advance_wb_err clear AS_EIO
and AS_ENOSPC when reporting an error. That should allow the new
function to better emulate the behavior of the old with respect to these
flags.
Link: http://lkml.kernel.org/r/20170922133331.28812-1-jlayton@kernel.org
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reported-by: Eryu Guan <eguan@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On powerpc, RODATA_TEST fails with message the following messages:
Freeing unused kernel memory: 528K
rodata_test: test data was not read only
This is because GCC allocates it to .data section:
c0695034 g O .data 00000004 rodata_test_data
Since commit 056b9d8a76 ("mm: remove rodata_test_data export, add
pr_fmt"), rodata_test_data is used only inside rodata_test.c By
declaring it static, it gets properly allocated into .rodata section
instead of .data:
c04df710 l O .rodata 00000004 rodata_test_data
Fixes: 056b9d8a76 ("mm: remove rodata_test_data export, add pr_fmt")
Link: http://lkml.kernel.org/r/20170921093729.1080368AC1@po15668-vm-win7.idsi0.si.c-s.fr
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Kees Cook <keescook@chromium.org>
Cc: Jinbum Park <jinb.park7@gmail.com>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The function is called from __meminit context and calls other __meminit
functions but isn't it self mark as such today:
WARNING: vmlinux.o(.text.unlikely+0x4516): Section mismatch in reference from the function init_reserved_page() to the function .meminit.text:early_pfn_to_nid()
The function init_reserved_page() references the function __meminit early_pfn_to_nid().
This is often because init_reserved_page lacks a __meminit annotation or the annotation of early_pfn_to_nid is wrong.
On most compilers, we don't notice this because the function gets
inlined all the time. Adding __meminit here fixes the harmless warning
for the old versions and is generally the correct annotation.
Link: http://lkml.kernel.org/r/20170915193149.901180-1-arnd@arndb.de
Fixes: 7e18adb4f8 ("mm: meminit: initialise remaining struct pages in parallel with kswapd")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix the situation when clear_bit() is called for page->private before
the page pointer is actually assigned. While at it, remove work_busy()
check because it is costly and does not give 100% guarantee anyway.
Signed-off-by: Vitaly Wool <vitalywool@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: <Oleksiy.Avramchenko@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrea brought to my attention that the L->{L,S} guarantees are
completely bogus for this case. I was looking at the diagram, from the
offending commit, when that _is_ the race, we had the load reordered
already.
What we need is at least S->L semantics, thus simply use
wq_has_sleeper() to serialize the call for good.
Link: http://lkml.kernel.org/r/20170914175313.GB811@linux-80c1.suse
Fixes: 46acef048a (mm,compaction: serialize waitqueue_active() checks)
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reported-by: Andrea Parri <parri.andrea@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix for 4.14, zone device page always have an elevated refcount of one
and thus page count sanity check in uncharge_page() is inappropriate for
them.
[mhocko@suse.com: nano-optimize VM_BUG_ON in uncharge_page]
Link: http://lkml.kernel.org/r/20170914190011.5217-1-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Evgeny Baskakov <ebaskakov@nvidia.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The following lockdep splat has been noticed during LTP testing
======================================================
WARNING: possible circular locking dependency detected
4.13.0-rc3-next-20170807 #12 Not tainted
------------------------------------------------------
a.out/4771 is trying to acquire lock:
(cpu_hotplug_lock.rw_sem){++++++}, at: [<ffffffff812b4668>] drain_all_stock.part.35+0x18/0x140
but task is already holding lock:
(&mm->mmap_sem){++++++}, at: [<ffffffff8106eb35>] __do_page_fault+0x175/0x530
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&mm->mmap_sem){++++++}:
lock_acquire+0xc9/0x230
__might_fault+0x70/0xa0
_copy_to_user+0x23/0x70
filldir+0xa7/0x110
xfs_dir2_sf_getdents.isra.10+0x20c/0x2c0 [xfs]
xfs_readdir+0x1fa/0x2c0 [xfs]
xfs_file_readdir+0x30/0x40 [xfs]
iterate_dir+0x17a/0x1a0
SyS_getdents+0xb0/0x160
entry_SYSCALL_64_fastpath+0x1f/0xbe
-> #2 (&type->i_mutex_dir_key#3){++++++}:
lock_acquire+0xc9/0x230
down_read+0x51/0xb0
lookup_slow+0xde/0x210
walk_component+0x160/0x250
link_path_walk+0x1a6/0x610
path_openat+0xe4/0xd50
do_filp_open+0x91/0x100
file_open_name+0xf5/0x130
filp_open+0x33/0x50
kernel_read_file_from_path+0x39/0x80
_request_firmware+0x39f/0x880
request_firmware_direct+0x37/0x50
request_microcode_fw+0x64/0xe0
reload_store+0xf7/0x180
dev_attr_store+0x18/0x30
sysfs_kf_write+0x44/0x60
kernfs_fop_write+0x113/0x1a0
__vfs_write+0x37/0x170
vfs_write+0xc7/0x1c0
SyS_write+0x58/0xc0
do_syscall_64+0x6c/0x1f0
return_from_SYSCALL_64+0x0/0x7a
-> #1 (microcode_mutex){+.+.+.}:
lock_acquire+0xc9/0x230
__mutex_lock+0x88/0x960
mutex_lock_nested+0x1b/0x20
microcode_init+0xbb/0x208
do_one_initcall+0x51/0x1a9
kernel_init_freeable+0x208/0x2a7
kernel_init+0xe/0x104
ret_from_fork+0x2a/0x40
-> #0 (cpu_hotplug_lock.rw_sem){++++++}:
__lock_acquire+0x153c/0x1550
lock_acquire+0xc9/0x230
cpus_read_lock+0x4b/0x90
drain_all_stock.part.35+0x18/0x140
try_charge+0x3ab/0x6e0
mem_cgroup_try_charge+0x7f/0x2c0
shmem_getpage_gfp+0x25f/0x1050
shmem_fault+0x96/0x200
__do_fault+0x1e/0xa0
__handle_mm_fault+0x9c3/0xe00
handle_mm_fault+0x16e/0x380
__do_page_fault+0x24a/0x530
do_page_fault+0x30/0x80
page_fault+0x28/0x30
other info that might help us debug this:
Chain exists of:
cpu_hotplug_lock.rw_sem --> &type->i_mutex_dir_key#3 --> &mm->mmap_sem
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&mm->mmap_sem);
lock(&type->i_mutex_dir_key#3);
lock(&mm->mmap_sem);
lock(cpu_hotplug_lock.rw_sem);
*** DEADLOCK ***
2 locks held by a.out/4771:
#0: (&mm->mmap_sem){++++++}, at: [<ffffffff8106eb35>] __do_page_fault+0x175/0x530
#1: (percpu_charge_mutex){+.+...}, at: [<ffffffff812b4c97>] try_charge+0x397/0x6e0
The problem is very similar to the one fixed by commit a459eeb7b8
("mm, page_alloc: do not depend on cpu hotplug locks inside the
allocator"). We are taking hotplug locks while we can be sitting on top
of basically arbitrary locks. This just calls for problems.
We can get rid of {get,put}_online_cpus, fortunately. We do not have to
be worried about races with memory hotplug because drain_local_stock,
which is called from both the WQ draining and the memory hotplug
contexts, is always operating on the local cpu stock with IRQs disabled.
The only thing to be careful about is that the target memcg doesn't
vanish while we are still in drain_all_stock so take a reference on it.
Link: http://lkml.kernel.org/r/20170913090023.28322-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Artem Savkov <asavkov@redhat.com>
Tested-by: Artem Savkov <asavkov@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrea has noticed that the oom_reaper doesn't invalidate the range via
mmu notifiers (mmu_notifier_invalidate_range_start/end) and that can
corrupt the memory of the kvm guest for example.
tlb_flush_mmu_tlbonly already invokes mmu notifiers but that is not
sufficient as per Andrea:
"mmu_notifier_invalidate_range cannot be used in replacement of
mmu_notifier_invalidate_range_start/end. For KVM
mmu_notifier_invalidate_range is a noop and rightfully so. A MMU
notifier implementation has to implement either ->invalidate_range
method or the invalidate_range_start/end methods, not both. And if you
implement invalidate_range_start/end like KVM is forced to do, calling
mmu_notifier_invalidate_range in common code is a noop for KVM.
For those MMU notifiers that can get away only implementing
->invalidate_range, the ->invalidate_range is implicitly called by
mmu_notifier_invalidate_range_end(). And only those secondary MMUs
that share the same pagetable with the primary MMU (like AMD iommuv2)
can get away only implementing ->invalidate_range"
As the callback is allowed to sleep and the implementation is out of
hand of the MM it is safer to simply bail out if there is an mmu
notifier registered. In order to not fail too early make the
mm_has_notifiers check under the oom_lock and have a little nap before
failing to give the current oom victim some more time to exit.
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20170913113427.2291-1-mhocko@kernel.org
Fixes: aac4536355 ("mm, oom: introduce oom reaper")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It is possible that on a (partially) unsuccessful page reclaim,
kref_put() called in z3fold_reclaim_page() does not yield page release,
but the page is released shortly afterwards by another thread. Then
z3fold_reclaim_page() would try to list_add() that (released) page again
which is obviously a bug.
To avoid that, spin_lock() has to be taken earlier, before the
kref_put() call mentioned earlier.
Link: http://lkml.kernel.org/r/20170913162937.bfff21c7d12b12a5f47639fd@gmail.com
Signed-off-by: Vitaly Wool <vitalywool@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: <Oleksiy.Avramchenko@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This fixes a bug in madvise() where if you'd try to soft offline a
hugepage via madvise(), while walking the address range you'd end up,
using the wrong page offset due to attempting to get the compound order
of a former but presently not compound page, due to dissolving the huge
page (since commit c3114a84f7: "mm: hugetlb: soft-offline: dissolve
source hugepage after successful migration").
As a result I ended up with all my free pages except one being offlined.
Link: http://lkml.kernel.org/r/20170912204306.GA12053@gmail.com
Fixes: c3114a84f7 ("mm: hugetlb: soft-offline: dissolve source hugepage after successful migration")
Signed-off-by: Alexandru Moise <00moses.alexander00@gmail.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In this place mm is unlocked, so vmas or list may change. Down read
mmap_sem to protect them from modifications.
Link: http://lkml.kernel.org/r/150512788393.10691.8868381099691121308.stgit@localhost.localdomain
Fixes: e86c59b1b1 ("mm/ksm: improve deduplication of zero pages with colouring")
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: zhong jiang <zhongjiang@huawei.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Laptop mode really wants to writeback the number of dirty
pages and inodes. Instead of calculating this in the caller,
just pass in 0 and let wakeup_flusher_threads() handle it.
Use the new wakeup_flusher_threads_bdi() instead of rolling
our own.
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Chris Mason <clm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Everybody is passing in 0 now, let's get rid of the argument.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The iterator functions pcpu_next_md_free_region and
pcpu_next_fit_region use the block offset to determine if they have
checked the area in the prior iteration. However, this causes an issue
when the block offset is greater than subsequent block contig hints. If
within the iterator it moves to check subsequent blocks, it may fail in
the second predicate due to the block offset not being cleared. Thus,
this causes the allocator to skip over blocks leading to false failures
when allocating from the reserved chunk. While this happens in the
general case as well, it will only fail if it cannot allocate a new
chunk.
This patch resets the block offset to 0 to pass the second predicate
when checking subseqent blocks within the iterator function.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reported-and-tested-by: Luis Henriques <lhenriques@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This patch fixes the starting offset used when scanning chunks to
compute the chunk statistics. The value start_offset (and end_offset)
are managed in bytes while the traversal occurs over bits. Thus for the
reserved and dynamic chunk, it may incorrectly skip over the initial
allocations.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Currently when mixing buffered reads and asynchronous direct writes it
is possible to end up with the situation where we have stale data in the
page cache while the new data is already written to disk. This is
permanent until the affected pages are flushed away. Despite the fact
that mixing buffered and direct IO is ill-advised it does pose a thread
for a data integrity, is unexpected and should be fixed.
Fix this by deferring completion of asynchronous direct writes to a
process context in the case that there are mapped pages to be found in
the inode. Later before the completion in dio_complete() invalidate
the pages in question. This ensures that after the completion the pages
in the written area are either unmapped, or populated with up-to-date
data. Also do the same for the iomap case which uses
iomap_dio_complete() instead.
This has a side effect of deferring the completion to a process context
for every AIO DIO that happens on inode that has pages mapped. However
since the consensus is that this is ill-advised practice the performance
implication should not be a problem.
This was based on proposal from Jeff Moyer, thanks!
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull nowait read support from Al Viro:
"Support IOCB_NOWAIT for buffered reads and block devices"
* 'work.read_write' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
block_dev: support RFW_NOWAIT on block device nodes
fs: support RWF_NOWAIT for buffered reads
fs: support IOCB_NOWAIT in generic_file_buffered_read
fs: pass iocb to do_generic_file_read
Pull more set_fs removal from Al Viro:
"Christoph's 'use kernel_read and friends rather than open-coding
set_fs()' series"
* 'work.set_fs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: unexport vfs_readv and vfs_writev
fs: unexport vfs_read and vfs_write
fs: unexport __vfs_read/__vfs_write
lustre: switch to kernel_write
gadget/f_mass_storage: stop messing with the address limit
mconsole: switch to kernel_read
btrfs: switch write_buf to kernel_write
net/9p: switch p9_fd_read to kernel_write
mm/nommu: switch do_mmap_private to kernel_read
serial2002: switch serial2002_tty_write to kernel_{read/write}
fs: make the buf argument to __kernel_write a void pointer
fs: fix kernel_write prototype
fs: fix kernel_read prototype
fs: move kernel_read to fs/read_write.c
fs: move kernel_write to fs/read_write.c
autofs4: switch autofs4_write to __kernel_write
ashmem: switch to ->read_iter
Merge misc fixes from Andrew Morton:
"A few leftovers"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
mm, page_owner: skip unnecessary stack_trace entries
arm64: stacktrace: avoid listing stacktrace functions in stacktrace
mm: treewide: remove GFP_TEMPORARY allocation flag
IB/mlx4: fix sprintf format warning
fscache: fix fscache_objlist_show format processing
lib/test_bitmap.c: use ULL suffix for 64-bit constants
procfs: remove unused variable
drivers/media/cec/cec-adap.c: fix build with gcc-4.4.4
idr: remove WARN_ON_ONCE() when trying to replace negative ID
Now that we have added breaks in the wait queue scan and allow bookmark
on scan position, we put this logic in the wake_up_page_bit function.
We can have very long page wait list in large system where multiple
pages share the same wait list. We break the wake up walk here to allow
other cpus a chance to access the list, and not to disable the interrupts
when traversing the list for too long. This reduces the interrupt and
rescheduling latency, and excessive page wait queue lock hold time.
[ v2: Remove bookmark_wake_function ]
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The page_owner stacktrace always begin as follows:
[<ffffff987bfd48f4>] save_stack+0x40/0xc8
[<ffffff987bfd4da8>] __set_page_owner+0x3c/0x6c
These two entries do not provide any useful information and limits the
available stacktrace depth. The page_owner stacktrace was skipping
caller function from stack entries but this was missed with commit
f2ca0b5571 ("mm/page_owner: use stackdepot to store stacktrace")
Example page_owner entry after the patch:
Page allocated via order 0, mask 0x8(ffffff80085fb714)
PFN 654411 type Movable Block 639 type CMA Flags 0x0(ffffffbe5c7f12c0)
[<ffffff9b64989c14>] post_alloc_hook+0x70/0x80
...
[<ffffff9b651216e8>] msm_comm_try_state+0x5f8/0x14f4
[<ffffff9b6512486c>] msm_vidc_open+0x5e4/0x7d0
[<ffffff9b65113674>] msm_v4l2_open+0xa8/0x224
Link: http://lkml.kernel.org/r/1504078343-28754-2-git-send-email-guptap@codeaurora.org
Fixes: f2ca0b5571 ("mm/page_owner: use stackdepot to store stacktrace")
Signed-off-by: Prakash Gupta <guptap@codeaurora.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
GFP_TEMPORARY was introduced by commit e12ba74d8f ("Group short-lived
and reclaimable kernel allocations") along with __GFP_RECLAIMABLE. It's
primary motivation was to allow users to tell that an allocation is
short lived and so the allocator can try to place such allocations close
together and prevent long term fragmentation. As much as this sounds
like a reasonable semantic it becomes much less clear when to use the
highlevel GFP_TEMPORARY allocation flag. How long is temporary? Can the
context holding that memory sleep? Can it take locks? It seems there is
no good answer for those questions.
The current implementation of GFP_TEMPORARY is basically GFP_KERNEL |
__GFP_RECLAIMABLE which in itself is tricky because basically none of
the existing caller provide a way to reclaim the allocated memory. So
this is rather misleading and hard to evaluate for any benefits.
I have checked some random users and none of them has added the flag
with a specific justification. I suspect most of them just copied from
other existing users and others just thought it might be a good idea to
use without any measuring. This suggests that GFP_TEMPORARY just
motivates for cargo cult usage without any reasoning.
I believe that our gfp flags are quite complex already and especially
those with highlevel semantic should be clearly defined to prevent from
confusion and abuse. Therefore I propose dropping GFP_TEMPORARY and
replace all existing users to simply use GFP_KERNEL. Please note that
SLAB users with shrinkers will still get __GFP_RECLAIMABLE heuristic and
so they will be placed properly for memory fragmentation prevention.
I can see reasons we might want some gfp flag to reflect shorterm
allocations but I propose starting from a clear semantic definition and
only then add users with proper justification.
This was been brought up before LSF this year by Matthew [1] and it
turned out that GFP_TEMPORARY really doesn't have a clear semantic. It
seems to be a heuristic without any measured advantage for most (if not
all) its current users. The follow up discussion has revealed that
opinions on what might be temporary allocation differ a lot between
developers. So rather than trying to tweak existing users into a
semantic which they haven't expected I propose to simply remove the flag
and start from scratch if we really need a semantic for short term
allocations.
[1] http://lkml.kernel.org/r/20170118054945.GD18349@bombadil.infradead.org
[akpm@linux-foundation.org: fix typo]
[akpm@linux-foundation.org: coding-style fixes]
[sfr@canb.auug.org.au: drm/i915: fix up]
Link: http://lkml.kernel.org/r/20170816144703.378d4f4d@canb.auug.org.au
Link: http://lkml.kernel.org/r/20170728091904.14627-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Neil Brown <neilb@suse.de>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The 0-day test bot found a performance regression that was tracked down to
switching x86 to the generic get_user_pages_fast() implementation:
http://lkml.kernel.org/r/20170710024020.GA26389@yexl-desktop
The regression was caused by the fact that we now use local_irq_save() +
local_irq_restore() in get_user_pages_fast() to disable interrupts.
In x86 implementation local_irq_disable() + local_irq_enable() was used.
The fix is to make get_user_pages_fast() use local_irq_disable(),
leaving local_irq_save() for __get_user_pages_fast() that can be called
with interrupts disabled.
Numbers for pinning a gigabyte of memory, one page a time, 20 repeats:
Before: Average: 14.91 ms, stddev: 0.45 ms
After: Average: 10.76 ms, stddev: 0.18 ms
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: linux-mm@kvack.org
Fixes: e585513b76 ("x86/mm/gup: Switch GUP to the generic get_user_page_fast() implementation")
Link: http://lkml.kernel.org/r/20170908215603.9189-3-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
If the 'kmalloc' fails, we must go through the existing error handling
path.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Fixes: 52ebea749a ("writeback: make backing_dev_info host cgroup-specific bdi_writebacks")
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Such that we can optimize __mem_cgroup_largest_soft_limit_node(). The
only overhead is the extra footprint for the cached pointer, but this
should not be an issue for mem_cgroup_tree_per_node.
[dave@stgolabs.net: brain fart #2]
Link: http://lkml.kernel.org/r/20170731160114.GE21328@linux-80c1.suse
Link: http://lkml.kernel.org/r/20170719014603.19029-17-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allow interval trees to quickly check for overlaps to avoid unnecesary
tree lookups in interval_tree_iter_first().
As of this patch, all interval tree flavors will require using a
'rb_root_cached' such that we can have the leftmost node easily
available. While most users will make use of this feature, those with
special functions (in addition to the generic insert, delete, search
calls) will avoid using the cached option as they can do funky things
with insertions -- for example, vma_interval_tree_insert_after().
[jglisse@redhat.com: fix deadlock from typo vm_lock_anon_vma()]
Link: http://lkml.kernel.org/r/20170808225719.20723-1-jglisse@redhat.com
Link: http://lkml.kernel.org/r/20170719014603.19029-12-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Doug Ledford <dledford@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Christian Benvenuti <benve@cisco.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
First, number of CPUs can't be negative number.
Second, different signnnedness leads to suboptimal code in the following
cases:
1)
kmalloc(nr_cpu_ids * sizeof(X));
"int" has to be sign extended to size_t.
2)
while (loff_t *pos < nr_cpu_ids)
MOVSXD is 1 byte longed than the same MOV.
Other cases exist as well. Basically compiler is told that nr_cpu_ids
can't be negative which can't be deduced if it is "int".
Code savings on allyesconfig kernel: -3KB
add/remove: 0/0 grow/shrink: 25/264 up/down: 261/-3631 (-3370)
function old new delta
coretemp_cpu_online 450 512 +62
rcu_init_one 1234 1272 +38
pci_device_probe 374 399 +25
...
pgdat_reclaimable_pages 628 556 -72
select_fallback_rq 446 369 -77
task_numa_find_cpu 1923 1807 -116
Link: http://lkml.kernel.org/r/20170819114959.GA30580@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
VMA and its address bounds checks are too late in this function. They
must have been verified earlier in the page fault sequence. Hence just
remove them.
Link: http://lkml.kernel.org/r/20170901130137.7617-1-khandual@linux.vnet.ibm.com
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Free frontswap_map if an error is encountered before enable_swap_info().
Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org> [4.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If initializing a small swap file fails because the swap file has a
problem (holes, etc.) then we need to free the cluster info as part of
cleanup. Unfortunately a previous patch changed the code to use kvzalloc
but did not change all the vfree calls to use kvfree.
Found by running generic/357 from xfstests.
Link: http://lkml.kernel.org/r/20170831233515.GR3775@magnolia
Fixes: 54f180d3c1 ("mm, swap: use kvzalloc to allocate some swap data structures")
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org> [4.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We are by error initializing alloc_flags before gfp_allowed_mask is
applied. This could cause problems after pm_restrict_gfp_mask() is called
during suspend operation. Apply gfp_allowed_mask before initializing
alloc_flags so that the first allocation attempt uses correct flags.
Link: http://lkml.kernel.org/r/201709020016.ADJ21342.OFLJHOOSMFVtFQ@I-love.SAKURA.ne.jp
Fixes: 83d4ca8148 ("mm, page_alloc: move __GFP_HARDWALL modifications out of the fastpath")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
online_mem_sections() accidentally marks online only the first section
in the given range. This is a typo which hasn't been noticed because I
haven't tested large 2GB blocks previously. All users of
pfn_to_online_page would get confused on the the rest of the pfn range
in the block.
All we need to fix this is to use iterator (pfn) rather than start_pfn.
Link: http://lkml.kernel.org/r/20170904112210.3401-1-mhocko@kernel.org
Fixes: 2d070eab2e ("mm: consider zone which is not fully populated to have holes")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Seen while reading the code, in handle_mm_fault(), in the case
arch_vma_access_permitted() is failing the call to
mem_cgroup_oom_disable() is not made.
To fix that, move the call to mem_cgroup_oom_enable() after calling
arch_vma_access_permitted() as it should not have entered the memcg OOM.
Link: http://lkml.kernel.org/r/1504625439-31313-1-git-send-email-ldufour@linux.vnet.ibm.com
Fixes: bae473a423 ("mm: introduce fault_env")
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Acked-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The fadvise() manpage is silent on fadvise()'s effect on memory-based
filesystems (shmem, hugetlbfs & ramfs) and pseudo file systems (procfs,
sysfs, kernfs). The current implementaion of fadvise is mostly a noop
for such filesystems except for FADV_DONTNEED which will trigger
expensive remote LRU cache draining. This patch makes the noop of
fadvise() on such file systems very explicit.
However this change has two side effects for ramfs and one for tmpfs.
First fadvise(FADV_DONTNEED) could remove the unmapped clean zero'ed
pages of ramfs (allocated through read, readahead & read fault) and
tmpfs (allocated through read fault). Also fadvise(FADV_WILLNEED) could
create such clean zero'ed pages for ramfs. This change removes those
possibilities.
One of our generic libraries does fadvise(FADV_DONTNEED). Recently we
observed high latency in fadvise() and noticed that the users have
started using tmpfs files and the latency was due to expensive remote
LRU cache draining. For normal tmpfs files (have data written on them),
fadvise(FADV_DONTNEED) will always trigger the unneeded remote cache
draining.
Link: http://lkml.kernel.org/r/20170818011023.181465-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
zs_stat_inc/dec/get() uses enum zs_stat_type for the stat type, however
some callers pass an enum fullness_group value. Change the type to int to
reflect the actual use of the functions and get rid of 'enum-conversion'
warnings
Link: http://lkml.kernel.org/r/20170731175000.56538-1-mka@chromium.org
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Doug Anderson <dianders@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
page_zone_id() is a specialized function to compare the zone for the pages
that are within the section range. If the section of the pages are
different, page_zone_id() can be different even if their zone is the same.
This wrong usage doesn't cause any actual problem since
__munlock_pagevec_fill() would be called again with failed index.
However, it's better to use more appropriate function here.
Link: http://lkml.kernel.org/r/1503559211-10259-1-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To avoid deviation, the per cpu number of NUMA stats in
vm_numa_stat_diff[] is included when a user *reads* the NUMA stats.
Since NUMA stats does not be read by users frequently, and kernel does not
need it to make a decision, it will not be a problem to make the readers
more expensive.
Link: http://lkml.kernel.org/r/1503568801-21305-4-git-send-email-kemi.wang@intel.com
Signed-off-by: Kemi Wang <kemi.wang@intel.com>
Reported-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Christopher Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Ying Huang <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is significant overhead in cache bouncing caused by zone counters
(NUMA associated counters) update in parallel in multi-threaded page
allocation (suggested by Dave Hansen).
This patch updates NUMA counter threshold to a fixed size of MAX_U16 - 2,
as a small threshold greatly increases the update frequency of the global
counter from local per cpu counter(suggested by Ying Huang).
The rationality is that these statistics counters don't affect the
kernel's decision, unlike other VM counters, so it's not a problem to use
a large threshold.
With this patchset, we see 31.3% drop of CPU cycles(537-->369) for per
single page allocation and reclaim on Jesper's page_bench03 benchmark.
Benchmark provided by Jesper D Brouer(increase loop times to 10000000):
https://github.com/netoptimizer/prototype-kernel/tree/master/kernel/mm/
bench
Threshold CPU cycles Throughput(88 threads)
32 799 241760478
64 640 301628829
125 537 358906028 <==> system by default (base)
256 468 412397590
512 428 450550704
4096 399 482520943
20000 394 489009617
30000 395 488017817
65533 369(-31.3%) 521661345(+45.3%) <==> with this patchset
N/A 342(-36.3%) 562900157(+56.8%) <==> disable zone_statistics
Link: http://lkml.kernel.org/r/1503568801-21305-3-git-send-email-kemi.wang@intel.com
Signed-off-by: Kemi Wang <kemi.wang@intel.com>
Reported-by: Jesper Dangaard Brouer <brouer@redhat.com>
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Suggested-by: Ying Huang <ying.huang@intel.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Christopher Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Separate NUMA statistics from zone statistics", v2.
Each page allocation updates a set of per-zone statistics with a call to
zone_statistics(). As discussed in 2017 MM summit, these are a
substantial source of overhead in the page allocator and are very rarely
consumed. This significant overhead in cache bouncing caused by zone
counters (NUMA associated counters) update in parallel in multi-threaded
page allocation (pointed out by Dave Hansen).
A link to the MM summit slides:
http://people.netfilter.org/hawk/presentations/MM-summit2017/MM-summit2017-JesperBrouer.pdf
To mitigate this overhead, this patchset separates NUMA statistics from
zone statistics framework, and update NUMA counter threshold to a fixed
size of MAX_U16 - 2, as a small threshold greatly increases the update
frequency of the global counter from local per cpu counter (suggested by
Ying Huang). The rationality is that these statistics counters don't
need to be read often, unlike other VM counters, so it's not a problem
to use a large threshold and make readers more expensive.
With this patchset, we see 31.3% drop of CPU cycles(537-->369, see
below) for per single page allocation and reclaim on Jesper's
page_bench03 benchmark. Meanwhile, this patchset keeps the same style
of virtual memory statistics with little end-user-visible effects (only
move the numa stats to show behind zone page stats, see the first patch
for details).
I did an experiment of single page allocation and reclaim concurrently
using Jesper's page_bench03 benchmark on a 2-Socket Broadwell-based
server (88 processors with 126G memory) with different size of threshold
of pcp counter.
Benchmark provided by Jesper D Brouer(increase loop times to 10000000):
https://github.com/netoptimizer/prototype-kernel/tree/master/kernel/mm/bench
Threshold CPU cycles Throughput(88 threads)
32 799 241760478
64 640 301628829
125 537 358906028 <==> system by default
256 468 412397590
512 428 450550704
4096 399 482520943
20000 394 489009617
30000 395 488017817
65533 369(-31.3%) 521661345(+45.3%) <==> with this patchset
N/A 342(-36.3%) 562900157(+56.8%) <==> disable zone_statistics
This patch (of 3):
In this patch, NUMA statistics is separated from zone statistics
framework, all the call sites of NUMA stats are changed to use
numa-stats-specific functions, it does not have any functionality change
except that the number of NUMA stats is shown behind zone page stats
when users *read* the zone info.
E.g. cat /proc/zoneinfo
***Base*** ***With this patch***
nr_free_pages 3976 nr_free_pages 3976
nr_zone_inactive_anon 0 nr_zone_inactive_anon 0
nr_zone_active_anon 0 nr_zone_active_anon 0
nr_zone_inactive_file 0 nr_zone_inactive_file 0
nr_zone_active_file 0 nr_zone_active_file 0
nr_zone_unevictable 0 nr_zone_unevictable 0
nr_zone_write_pending 0 nr_zone_write_pending 0
nr_mlock 0 nr_mlock 0
nr_page_table_pages 0 nr_page_table_pages 0
nr_kernel_stack 0 nr_kernel_stack 0
nr_bounce 0 nr_bounce 0
nr_zspages 0 nr_zspages 0
numa_hit 0 *nr_free_cma 0*
numa_miss 0 numa_hit 0
numa_foreign 0 numa_miss 0
numa_interleave 0 numa_foreign 0
numa_local 0 numa_interleave 0
numa_other 0 numa_local 0
*nr_free_cma 0* numa_other 0
... ...
vm stats threshold: 10 vm stats threshold: 10
... ...
The next patch updates the numa stats counter size and threshold.
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/1503568801-21305-2-git-send-email-kemi.wang@intel.com
Signed-off-by: Kemi Wang <kemi.wang@intel.com>
Reported-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christopher Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Ying Huang <ying.huang@intel.com>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Flags argument has been copied into vmf.flags and it is not changed in
between. Hence a single write access check can be used for both PUD and
PMD.
Link: http://lkml.kernel.org/r/20170823082839.1812-1-khandual@linux.vnet.ibm.com
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While reading the code I found that offset_il_node() has a vm_area_struct
pointer parameter which is unused.
Link: http://lkml.kernel.org/r/1502899755-23146-1-git-send-email-ldufour@linux.vnet.ibm.com
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This moves all new code including new page migration helper behind kernel
Kconfig option so that there is no codee bloat for arch or user that do
not want to use HMM or any of its associated features.
arm allyesconfig (without all the patchset, then with and this patch):
text data bss dec hex filename
83721896 46511131 27582964 157815991 96814b7 ../without/vmlinux
83722364 46511131 27582964 157816459 968168b vmlinux
[jglisse@redhat.com: struct hmm is only use by HMM mirror functionality]
Link: http://lkml.kernel.org/r/20170825213133.27286-1-jglisse@redhat.com
[sfr@canb.auug.org.au: fix build (arm multi_v7_defconfig)]
Link: http://lkml.kernel.org/r/20170828181849.323ab81b@canb.auug.org.au
Link: http://lkml.kernel.org/r/20170818032858.7447-1-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Unlike unaddressable memory, coherent device memory has a real resource
associated with it on the system (as CPU can address it). Add a new
helper to hotplug such memory within the HMM framework.
Link: http://lkml.kernel.org/r/20170817000548.32038-20-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Platform with advance system bus (like CAPI or CCIX) allow device memory
to be accessible from CPU in a cache coherent fashion. Add a new type of
ZONE_DEVICE to represent such memory. The use case are the same as for
the un-addressable device memory but without all the corners cases.
Link: http://lkml.kernel.org/r/20170817000548.32038-19-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This allows callers of migrate_vma() to allocate new page for empty CPU
page table entry (pte_none or back by zero page). This is only for
anonymous memory and it won't allow new page to be instanced if the
userfaultfd is armed.
This is useful to device driver that want to migrate a range of virtual
address and would rather allocate new memory than having to fault later
on.
Link: http://lkml.kernel.org/r/20170817000548.32038-18-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allow to unmap and restore special swap entry of un-addressable
ZONE_DEVICE memory.
Link: http://lkml.kernel.org/r/20170817000548.32038-17-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Common case for migration of virtual address range is page are map only
once inside the vma in which migration is taking place. Because we
already walk the CPU page table for that range we can directly do the
unmap there and setup special migration swap entry.
Link: http://lkml.kernel.org/r/20170817000548.32038-16-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Evgeny Baskakov <ebaskakov@nvidia.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com>
Signed-off-by: Sherry Cheung <SCheung@nvidia.com>
Signed-off-by: Subhash Gutti <sgutti@nvidia.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch add a new memory migration helpers, which migrate memory
backing a range of virtual address of a process to different memory (which
can be allocated through special allocator). It differs from numa
migration by working on a range of virtual address and thus by doing
migration in chunk that can be large enough to use DMA engine or special
copy offloading engine.
Expected users are any one with heterogeneous memory where different
memory have different characteristics (latency, bandwidth, ...). As an
example IBM platform with CAPI bus can make use of this feature to migrate
between regular memory and CAPI device memory. New CPU architecture with
a pool of high performance memory not manage as cache but presented as
regular memory (while being faster and with lower latency than DDR) will
also be prime user of this patch.
Migration to private device memory will be useful for device that have
large pool of such like GPU, NVidia plans to use HMM for that.
Link: http://lkml.kernel.org/r/20170817000548.32038-15-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Evgeny Baskakov <ebaskakov@nvidia.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com>
Signed-off-by: Sherry Cheung <SCheung@nvidia.com>
Signed-off-by: Subhash Gutti <sgutti@nvidia.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce a new migration mode that allow to offload the copy to a device
DMA engine. This changes the workflow of migration and not all
address_space migratepage callback can support this.
This is intended to be use by migrate_vma() which itself is use for thing
like HMM (see include/linux/hmm.h).
No additional per-filesystem migratepage testing is needed. I disables
MIGRATE_SYNC_NO_COPY in all problematic migratepage() callback and i
added comment in those to explain why (part of this patch). The commit
message is unclear it should say that any callback that wish to support
this new mode need to be aware of the difference in the migration flow
from other mode.
Some of these callbacks do extra locking while copying (aio, zsmalloc,
balloon, ...) and for DMA to be effective you want to copy multiple
pages in one DMA operations. But in the problematic case you can not
easily hold the extra lock accross multiple call to this callback.
Usual flow is:
For each page {
1 - lock page
2 - call migratepage() callback
3 - (extra locking in some migratepage() callback)
4 - migrate page state (freeze refcount, update page cache, buffer
head, ...)
5 - copy page
6 - (unlock any extra lock of migratepage() callback)
7 - return from migratepage() callback
8 - unlock page
}
The new mode MIGRATE_SYNC_NO_COPY:
1 - lock multiple pages
For each page {
2 - call migratepage() callback
3 - abort in all problematic migratepage() callback
4 - migrate page state (freeze refcount, update page cache, buffer
head, ...)
} // finished all calls to migratepage() callback
5 - DMA copy multiple pages
6 - unlock all the pages
To support MIGRATE_SYNC_NO_COPY in the problematic case we would need a
new callback migratepages() (for instance) that deals with multiple
pages in one transaction.
Because the problematic cases are not important for current usage I did
not wanted to complexify this patchset even more for no good reason.
Link: http://lkml.kernel.org/r/20170817000548.32038-14-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This introduce a dummy HMM device class so device driver can use it to
create hmm_device for the sole purpose of registering device memory. It
is useful to device driver that want to manage multiple physical device
memory under same struct device umbrella.
Link: http://lkml.kernel.org/r/20170817000548.32038-13-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Evgeny Baskakov <ebaskakov@nvidia.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com>
Signed-off-by: Sherry Cheung <SCheung@nvidia.com>
Signed-off-by: Subhash Gutti <sgutti@nvidia.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This introduce a simple struct and associated helpers for device driver to
use when hotpluging un-addressable device memory as ZONE_DEVICE. It will
find a unuse physical address range and trigger memory hotplug for it
which allocates and initialize struct page for the device memory.
Device driver should use this helper during device initialization to
hotplug the device memory. It should only need to remove the memory once
the device is going offline (shutdown or hotremove). There should not be
any userspace API to hotplug memory expect maybe for host device driver to
allow to add more memory to a guest device driver.
Device's memory is manage by the device driver and HMM only provides
helpers to that effect.
Link: http://lkml.kernel.org/r/20170817000548.32038-12-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Evgeny Baskakov <ebaskakov@nvidia.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com>
Signed-off-by: Sherry Cheung <SCheung@nvidia.com>
Signed-off-by: Subhash Gutti <sgutti@nvidia.com>
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
HMM pages (private or public device pages) are ZONE_DEVICE page and thus
need special handling when it comes to lru or refcount. This patch make
sure that memcontrol properly handle those when it face them. Those pages
are use like regular pages in a process address space either as anonymous
page or as file back page. So from memcg point of view we want to handle
them like regular page for now at least.
Link: http://lkml.kernel.org/r/20170817000548.32038-11-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
HMM pages (private or public device pages) are ZONE_DEVICE page and
thus you can not use page->lru fields of those pages. This patch
re-arrange the uncharge to allow single page to be uncharge without
modifying the lru field of the struct page.
There is no change to memcontrol logic, it is the same as it was
before this patch.
Link: http://lkml.kernel.org/r/20170817000548.32038-10-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A ZONE_DEVICE page that reach a refcount of 1 is free ie no longer have
any user. For device private pages this is important to catch and thus we
need to special case put_page() for this.
Link: http://lkml.kernel.org/r/20170817000548.32038-9-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
HMM (heterogeneous memory management) need struct page to support
migration from system main memory to device memory. Reasons for HMM and
migration to device memory is explained with HMM core patch.
This patch deals with device memory that is un-addressable memory (ie CPU
can not access it). Hence we do not want those struct page to be manage
like regular memory. That is why we extend ZONE_DEVICE to support
different types of memory.
A persistent memory type is define for existing user of ZONE_DEVICE and a
new device un-addressable type is added for the un-addressable memory
type. There is a clear separation between what is expected from each
memory type and existing user of ZONE_DEVICE are un-affected by new
requirement and new use of the un-addressable type. All specific code
path are protect with test against the memory type.
Because memory is un-addressable we use a new special swap type for when a
page is migrated to device memory (this reduces the number of maximum swap
file).
The main two additions beside memory type to ZONE_DEVICE is two callbacks.
First one, page_free() is call whenever page refcount reach 1 (which
means the page is free as ZONE_DEVICE page never reach a refcount of 0).
This allow device driver to manage its memory and associated struct page.
The second callback page_fault() happens when there is a CPU access to an
address that is back by a device page (which are un-addressable by the
CPU). This callback is responsible to migrate the page back to system
main memory. Device driver can not block migration back to system memory,
HMM make sure that such page can not be pin into device memory.
If device is in some error condition and can not migrate memory back then
a CPU page fault to device memory should end with SIGBUS.
[arnd@arndb.de: fix warning]
Link: http://lkml.kernel.org/r/20170823133213.712917-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20170817000548.32038-8-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This handles page fault on behalf of device driver, unlike
handle_mm_fault() it does not trigger migration back to system memory for
device memory.
Link: http://lkml.kernel.org/r/20170817000548.32038-6-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Evgeny Baskakov <ebaskakov@nvidia.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com>
Signed-off-by: Sherry Cheung <SCheung@nvidia.com>
Signed-off-by: Subhash Gutti <sgutti@nvidia.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This does not use existing page table walker because we want to share
same code for our page fault handler.
Link: http://lkml.kernel.org/r/20170817000548.32038-5-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Evgeny Baskakov <ebaskakov@nvidia.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com>
Signed-off-by: Sherry Cheung <SCheung@nvidia.com>
Signed-off-by: Subhash Gutti <sgutti@nvidia.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a heterogeneous memory management (HMM) process address space
mirroring. In a nutshell this provide an API to mirror process address
space on a device. This boils down to keeping CPU and device page table
synchronize (we assume that both device and CPU are cache coherent like
PCIe device can be).
This patch provide a simple API for device driver to achieve address space
mirroring thus avoiding each device driver to grow its own CPU page table
walker and its own CPU page table synchronization mechanism.
This is useful for NVidia GPU >= Pascal, Mellanox IB >= mlx5 and more
hardware in the future.
[jglisse@redhat.com: fix hmm for "mmu_notifier kill invalidate_page callback"]
Link: http://lkml.kernel.org/r/20170830231955.GD9445@redhat.com
Link: http://lkml.kernel.org/r/20170817000548.32038-4-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Evgeny Baskakov <ebaskakov@nvidia.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com>
Signed-off-by: Sherry Cheung <SCheung@nvidia.com>
Signed-off-by: Subhash Gutti <sgutti@nvidia.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
HMM provides 3 separate types of functionality:
- Mirroring: synchronize CPU page table and device page table
- Device memory: allocating struct page for device memory
- Migration: migrating regular memory to device memory
This patch introduces some common helpers and definitions to all of
those 3 functionality.
Link: http://lkml.kernel.org/r/20170817000548.32038-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Evgeny Baskakov <ebaskakov@nvidia.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com>
Signed-off-by: Sherry Cheung <SCheung@nvidia.com>
Signed-off-by: Subhash Gutti <sgutti@nvidia.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Soft dirty bit is designed to keep tracked over page migration. This
patch makes it work in the same manner for thp migration too.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When THP migration is being used, memory management code needs to handle
pmd migration entries properly. This patch uses !pmd_present() or
is_swap_pmd() (depending on whether pmd_none() needs separate code or
not) to check pmd migration entries at the places where a pmd entry is
present.
Since pmd-related code uses split_huge_page(), split_huge_pmd(),
pmd_trans_huge(), pmd_trans_unstable(), or
pmd_none_or_trans_huge_or_clear_bad(), this patch:
1. adds pmd migration entry split code in split_huge_pmd(),
2. takes care of pmd migration entries whenever pmd_trans_huge() is present,
3. makes pmd_none_or_trans_huge_or_clear_bad() pmd migration entry aware.
Since split_huge_page() uses split_huge_pmd() and pmd_trans_unstable()
is equivalent to pmd_none_or_trans_huge_or_clear_bad(), we do not change
them.
Until this commit, a pmd entry should be:
1. pointing to a pte page,
2. is_swap_pmd(),
3. pmd_trans_huge(),
4. pmd_devmap(), or
5. pmd_none().
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add thp migration's core code, including conversions between a PMD entry
and a swap entry, setting PMD migration entry, removing PMD migration
entry, and waiting on PMD migration entries.
This patch makes it possible to support thp migration. If you fail to
allocate a destination page as a thp, you just split the source thp as
we do now, and then enter the normal page migration. If you succeed to
allocate destination thp, you enter thp migration. Subsequent patches
actually enable thp migration for each caller of page migration by
allowing its get_new_page() callback to allocate thps.
[zi.yan@cs.rutgers.edu: fix gcc-4.9.0 -Wmissing-braces warning]
Link: http://lkml.kernel.org/r/A0ABA698-7486-46C3-B209-E95A9048B22C@cs.rutgers.edu
[akpm@linux-foundation.org: fix x86_64 allnoconfig warning]
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce CONFIG_ARCH_ENABLE_THP_MIGRATION to limit thp migration
functionality to x86_64, which should be safer at the first step.
Link: http://lkml.kernel.org/r/20170717193955.20207-5-zi.yan@sent.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Reviewed-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
TTU_MIGRATION is used to convert pte into migration entry until thp
split completes. This behavior conflicts with thp migration added later
patches, so let's introduce a new TTU flag specifically for freezing.
try_to_unmap() is used both for thp split (via freeze_page()) and page
migration (via __unmap_and_move()). In freeze_page(), ttu_flag given
for head page is like below (assuming anonymous thp):
(TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS | TTU_RMAP_LOCKED | \
TTU_MIGRATION | TTU_SPLIT_HUGE_PMD)
and ttu_flag given for tail pages is:
(TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS | TTU_RMAP_LOCKED | \
TTU_MIGRATION)
__unmap_and_move() calls try_to_unmap() with ttu_flag:
(TTU_MIGRATION | TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS)
Now I'm trying to insert a branch for thp migration at the top of
try_to_unmap_one() like below
static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
unsigned long address, void *arg)
{
...
/* PMD-mapped THP migration entry */
if (!pvmw.pte && (flags & TTU_MIGRATION)) {
if (!PageAnon(page))
continue;
set_pmd_migration_entry(&pvmw, page);
continue;
}
...
}
so try_to_unmap() for tail pages called by thp split can go into thp
migration code path (which converts *pmd* into migration entry), while
the expectation is to freeze thp (which converts *pte* into migration
entry.)
I detected this failure as a "bad page state" error in a testcase where
split_huge_page() is called from queue_pages_pte_range().
Link: http://lkml.kernel.org/r/20170717193955.20207-4-zi.yan@sent.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: page migration enhancement for thp", v9.
Motivations:
1. THP migration becomes important in the upcoming heterogeneous memory
systems. As David Nellans from NVIDIA pointed out from other threads
(http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1349227.html),
future GPUs or other accelerators will have their memory managed by
operating systems. Moving data into and out of these memory nodes
efficiently is critical to applications that use GPUs or other
accelerators. Existing page migration only supports base pages, which
has a very low memory bandwidth utilization. My experiments (see
below) show THP migration can migrate pages more efficiently.
2. Base page migration vs THP migration throughput.
Here are cross-socket page migration results from calling
move_pages() syscall:
In x86_64, a Intel two-socket E5-2640v3 box,
- single 4KB base page migration takes 62.47 us, using 0.06 GB/s BW,
- single 2MB THP migration takes 658.54 us, using 2.97 GB/s BW,
- 512 4KB base page migration takes 1987.38 us, using 0.98 GB/s BW.
In ppc64, a two-socket Power8 box,
- single 64KB base page migration takes 49.3 us, using 1.24 GB/s BW,
- single 16MB THP migration takes 2202.17 us, using 7.10 GB/s BW,
- 256 64KB base page migration takes 2543.65 us, using 6.14 GB/s BW.
THP migration can give us 3x and 1.15x throughput over base page
migration in x86_64 and ppc64 respectivley.
You can test it out by using the code here:
https://github.com/x-y-z/thp-migration-bench
3. Existing page migration splits THP before migration and cannot
guarantee the migrated pages are still contiguous. Contiguity is
always what GPUs and accelerators look for. Without THP migration,
khugepaged needs to do extra work to reassemble the migrated pages
back to THPs.
This patch (of 10):
Introduce a separate check routine related to MPOL_MF_INVERT flag. This
patch just does cleanup, no behavioral change.
Link: http://lkml.kernel.org/r/20170717193955.20207-2-zi.yan@sent.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull block layer updates from Jens Axboe:
"This is the first pull request for 4.14, containing most of the code
changes. It's a quiet series this round, which I think we needed after
the churn of the last few series. This contains:
- Fix for a registration race in loop, from Anton Volkov.
- Overflow complaint fix from Arnd for DAC960.
- Series of drbd changes from the usual suspects.
- Conversion of the stec/skd driver to blk-mq. From Bart.
- A few BFQ improvements/fixes from Paolo.
- CFQ improvement from Ritesh, allowing idling for group idle.
- A few fixes found by Dan's smatch, courtesy of Dan.
- A warning fixup for a race between changing the IO scheduler and
device remova. From David Jeffery.
- A few nbd fixes from Josef.
- Support for cgroup info in blktrace, from Shaohua.
- Also from Shaohua, new features in the null_blk driver to allow it
to actually hold data, among other things.
- Various corner cases and error handling fixes from Weiping Zhang.
- Improvements to the IO stats tracking for blk-mq from me. Can
drastically improve performance for fast devices and/or big
machines.
- Series from Christoph removing bi_bdev as being needed for IO
submission, in preparation for nvme multipathing code.
- Series from Bart, including various cleanups and fixes for switch
fall through case complaints"
* 'for-4.14/block' of git://git.kernel.dk/linux-block: (162 commits)
kernfs: checking for IS_ERR() instead of NULL
drbd: remove BIOSET_NEED_RESCUER flag from drbd_{md_,}io_bio_set
drbd: Fix allyesconfig build, fix recent commit
drbd: switch from kmalloc() to kmalloc_array()
drbd: abort drbd_start_resync if there is no connection
drbd: move global variables to drbd namespace and make some static
drbd: rename "usermode_helper" to "drbd_usermode_helper"
drbd: fix race between handshake and admin disconnect/down
drbd: fix potential deadlock when trying to detach during handshake
drbd: A single dot should be put into a sequence.
drbd: fix rmmod cleanup, remove _all_ debugfs entries
drbd: Use setup_timer() instead of init_timer() to simplify the code.
drbd: fix potential get_ldev/put_ldev refcount imbalance during attach
drbd: new disk-option disable-write-same
drbd: Fix resource role for newly created resources in events2
drbd: mark symbols static where possible
drbd: Send P_NEG_ACK upon write error in protocol != C
drbd: add explicit plugging when submitting batches
drbd: change list_for_each_safe to while(list_first_entry_or_null)
drbd: introduce drbd_recv_header_maybe_unplug
...
Nothing really major this release, despite quite a lot of activity. Just lots of
things all over the place.
Some things of note include:
- Access via perf to a new type of PMU (IMC) on Power9, which can count both
core events as well as nest unit events (Memory controller etc).
- Optimisations to the radix MMU TLB flushing, mostly to avoid unnecessary Page
Walk Cache (PWC) flushes when the structure of the tree is not changing.
- Reworks/cleanups of do_page_fault() to modernise it and bring it closer to
other architectures where possible.
- Rework of our page table walking so that THP updates only need to send IPIs
to CPUs where the affected mm has run, rather than all CPUs.
- The size of our vmalloc area is increased to 56T on 64-bit hash MMU systems.
This avoids problems with the percpu allocator on systems with very sparse
NUMA layouts.
- STRICT_KERNEL_RWX support on PPC32.
- A new sched domain topology for Power9, to capture the fact that pairs of
cores may share an L2 cache.
- Power9 support for VAS, which is a new mechanism for accessing coprocessors,
and initial support for using it with the NX compression accelerator.
- Major work on the instruction emulation support, adding support for many new
instructions, and reworking it so it can be used to implement the emulation
needed to fixup alignment faults.
- Support for guests under PowerVM to use the Power9 XIVE interrupt controller.
And probably that many things again that are almost as interesting, but I had to
keep the list short. Plus the usual fixes and cleanups as always.
Thanks to:
Alexey Kardashevskiy, Alistair Popple, Andreas Schwab, Aneesh Kumar K.V, Anju
T Sudhakar, Arvind Yadav, Balbir Singh, Benjamin Herrenschmidt, Bhumika Goyal,
Breno Leitao, Bryant G. Ly, Christophe Leroy, Cédric Le Goater, Dan Carpenter,
Dou Liyang, Frederic Barrat, Gautham R. Shenoy, Geliang Tang, Geoff Levand,
Hannes Reinecke, Haren Myneni, Ivan Mikhaylov, John Allen, Julia Lawall, LABBE
Corentin, Laurentiu Tudor, Madhavan Srinivasan, Markus Elfring, Masahiro
Yamada, Matt Brown, Michael Neuling, Murilo Opsfelder Araujo, Nathan Fontenot,
Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran, Paul Mackerras, Rashmica
Gupta, Rob Herring, Rui Teng, Sam Bobroff, Santosh Sivaraj, Scott Wood,
Shilpasri G Bhat, Sukadev Bhattiprolu, Suraj Jitindar Singh, Tobin C. Harding,
Victor Aoqui.
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Merge tag 'powerpc-4.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Nothing really major this release, despite quite a lot of activity.
Just lots of things all over the place.
Some things of note include:
- Access via perf to a new type of PMU (IMC) on Power9, which can
count both core events as well as nest unit events (Memory
controller etc).
- Optimisations to the radix MMU TLB flushing, mostly to avoid
unnecessary Page Walk Cache (PWC) flushes when the structure of the
tree is not changing.
- Reworks/cleanups of do_page_fault() to modernise it and bring it
closer to other architectures where possible.
- Rework of our page table walking so that THP updates only need to
send IPIs to CPUs where the affected mm has run, rather than all
CPUs.
- The size of our vmalloc area is increased to 56T on 64-bit hash MMU
systems. This avoids problems with the percpu allocator on systems
with very sparse NUMA layouts.
- STRICT_KERNEL_RWX support on PPC32.
- A new sched domain topology for Power9, to capture the fact that
pairs of cores may share an L2 cache.
- Power9 support for VAS, which is a new mechanism for accessing
coprocessors, and initial support for using it with the NX
compression accelerator.
- Major work on the instruction emulation support, adding support for
many new instructions, and reworking it so it can be used to
implement the emulation needed to fixup alignment faults.
- Support for guests under PowerVM to use the Power9 XIVE interrupt
controller.
And probably that many things again that are almost as interesting,
but I had to keep the list short. Plus the usual fixes and cleanups as
always.
Thanks to: Alexey Kardashevskiy, Alistair Popple, Andreas Schwab,
Aneesh Kumar K.V, Anju T Sudhakar, Arvind Yadav, Balbir Singh,
Benjamin Herrenschmidt, Bhumika Goyal, Breno Leitao, Bryant G. Ly,
Christophe Leroy, Cédric Le Goater, Dan Carpenter, Dou Liyang,
Frederic Barrat, Gautham R. Shenoy, Geliang Tang, Geoff Levand, Hannes
Reinecke, Haren Myneni, Ivan Mikhaylov, John Allen, Julia Lawall,
LABBE Corentin, Laurentiu Tudor, Madhavan Srinivasan, Markus Elfring,
Masahiro Yamada, Matt Brown, Michael Neuling, Murilo Opsfelder Araujo,
Nathan Fontenot, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran,
Paul Mackerras, Rashmica Gupta, Rob Herring, Rui Teng, Sam Bobroff,
Santosh Sivaraj, Scott Wood, Shilpasri G Bhat, Sukadev Bhattiprolu,
Suraj Jitindar Singh, Tobin C. Harding, Victor Aoqui"
* tag 'powerpc-4.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (321 commits)
powerpc/xive: Fix section __init warning
powerpc: Fix kernel crash in emulation of vector loads and stores
powerpc/xive: improve debugging macros
powerpc/xive: add XIVE Exploitation Mode to CAS
powerpc/xive: introduce H_INT_ESB hcall
powerpc/xive: add the HW IRQ number under xive_irq_data
powerpc/xive: introduce xive_esb_write()
powerpc/xive: rename xive_poke_esb() in xive_esb_read()
powerpc/xive: guest exploitation of the XIVE interrupt controller
powerpc/xive: introduce a common routine xive_queue_page_alloc()
powerpc/sstep: Avoid used uninitialized error
axonram: Return directly after a failed kzalloc() in axon_ram_probe()
axonram: Improve a size determination in axon_ram_probe()
axonram: Delete an error message for a failed memory allocation in axon_ram_probe()
powerpc/powernv/npu: Move tlb flush before launching ATSD
powerpc/macintosh: constify wf_sensor_ops structures
powerpc/iommu: Use permission-specific DEVICE_ATTR variants
powerpc/eeh: Delete an error out of memory message at init time
powerpc/mm: Use seq_putc() in two functions
macintosh: Convert to using %pOF instead of full_name
...
Pull cgroup updates from Tejun Heo:
"Several notable changes this cycle:
- Thread mode was merged. This will be used for cgroup2 support for
CPU and possibly other controllers. Unfortunately, CPU controller
cgroup2 support didn't make this pull request but most contentions
have been resolved and the support is likely to be merged before
the next merge window.
- cgroup.stat now shows the number of descendant cgroups.
- cpuset now can enable the easier-to-configure v2 behavior on v1
hierarchy"
* 'for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (21 commits)
cpuset: Allow v2 behavior in v1 cgroup
cgroup: Add mount flag to enable cpuset to use v2 behavior in v1 cgroup
cgroup: remove unneeded checks
cgroup: misc changes
cgroup: short-circuit cset_cgroup_from_root() on the default hierarchy
cgroup: re-use the parent pointer in cgroup_destroy_locked()
cgroup: add cgroup.stat interface with basic hierarchy stats
cgroup: implement hierarchy limits
cgroup: keep track of number of descent cgroups
cgroup: add comment to cgroup_enable_threaded()
cgroup: remove unnecessary empty check when enabling threaded mode
cgroup: update debug controller to print out thread mode information
cgroup: implement cgroup v2 thread support
cgroup: implement CSS_TASK_ITER_THREADED
cgroup: introduce cgroup->dom_cgrp and threaded css_set handling
cgroup: add @flags to css_task_iter_start() and implement CSS_TASK_ITER_PROCS
cgroup: reorganize cgroup.procs / task write path
cgroup: replace css_set walking populated test with testing cgrp->nr_populated_csets
cgroup: distinguish local and children populated states
cgroup: remove now unused list_head @pending in cgroup_apply_cftypes()
...
Pull percpu updates from Tejun Heo:
"A lot of changes for percpu this time around. percpu inherited the
same area allocator from the original pre-virtual-address-mapped
implementation. This was from the time when percpu allocator wasn't
used all that much and the implementation was focused on simplicity,
with the unfortunate computational complexity of O(number of areas
allocated from the chunk) per alloc / free.
With the increase in percpu usage, we're hitting cases where the lack
of scalability is hurting. The most prominent one right now is bpf
perpcu map creation / destruction which may allocate and free a lot of
entries consecutively and it's likely that the problem will become
more prominent in the future.
To address the issue, Dennis replaced the area allocator with hinted
bitmap allocator which is more consistent. While the new allocator
does perform a bit worse in some cases, it outperforms the old
allocator way more than an order of magnitude in other more common
scenarios while staying mostly flat in CPU overhead and completely
flat in memory consumption"
* 'for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (27 commits)
percpu: update header to contain bitmap allocator explanation.
percpu: update pcpu_find_block_fit to use an iterator
percpu: use metadata blocks to update the chunk contig hint
percpu: update free path to take advantage of contig hints
percpu: update alloc path to only scan if contig hints are broken
percpu: keep track of the best offset for contig hints
percpu: skip chunks if the alloc does not fit in the contig hint
percpu: add first_bit to keep track of the first free in the bitmap
percpu: introduce bitmap metadata blocks
percpu: replace area map allocator with bitmap
percpu: generalize bitmap (un)populated iterators
percpu: increase minimum percpu allocation size and align first regions
percpu: introduce nr_empty_pop_pages to help empty page accounting
percpu: change the number of pages marked in the first_chunk pop bitmap
percpu: combine percpu address checks
percpu: modify base_addr to be region specific
percpu: setup_first_chunk rename schunk/dchunk to chunk
percpu: end chunk area maps page aligned for the populated bitmap
percpu: unify allocation of schunk and dchunk
percpu: setup_first_chunk remove dyn_size and consolidate logic
...
Merge updates from Andrew Morton:
- various misc bits
- DAX updates
- OCFS2
- most of MM
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (119 commits)
mm,fork: introduce MADV_WIPEONFORK
x86,mpx: make mpx depend on x86-64 to free up VMA flag
mm: add /proc/pid/smaps_rollup
mm: hugetlb: clear target sub-page last when clearing huge page
mm: oom: let oom_reap_task and exit_mmap run concurrently
swap: choose swap device according to numa node
mm: replace TIF_MEMDIE checks by tsk_is_oom_victim
mm, oom: do not rely on TIF_MEMDIE for memory reserves access
z3fold: use per-cpu unbuddied lists
mm, swap: don't use VMA based swap readahead if HDD is used as swap
mm, swap: add sysfs interface for VMA based swap readahead
mm, swap: VMA based swap readahead
mm, swap: fix swap readahead marking
mm, swap: add swap readahead hit statistics
mm/vmalloc.c: don't reinvent the wheel but use existing llist API
mm/vmstat.c: fix wrong comment
selftests/memfd: add memfd_create hugetlbfs selftest
mm/shmem: add hugetlbfs support to memfd_create()
mm, devm_memremap_pages: use multi-order radix for ZONE_DEVICE lookups
mm/vmalloc.c: halve the number of comparisons performed in pcpu_get_vm_areas()
...
Introduce MADV_WIPEONFORK semantics, which result in a VMA being empty
in the child process after fork. This differs from MADV_DONTFORK in one
important way.
If a child process accesses memory that was MADV_WIPEONFORK, it will get
zeroes. The address ranges are still valid, they are just empty.
If a child process accesses memory that was MADV_DONTFORK, it will get a
segmentation fault, since those address ranges are no longer valid in
the child after fork.
Since MADV_DONTFORK also seems to be used to allow very large programs
to fork in systems with strict memory overcommit restrictions, changing
the semantics of MADV_DONTFORK might break existing programs.
MADV_WIPEONFORK only works on private, anonymous VMAs.
The use case is libraries that store or cache information, and want to
know that they need to regenerate it in the child process after fork.
Examples of this would be:
- systemd/pulseaudio API checks (fail after fork) (replacing a getpid
check, which is too slow without a PID cache)
- PKCS#11 API reinitialization check (mandated by specification)
- glibc's upcoming PRNG (reseed after fork)
- OpenSSL PRNG (reseed after fork)
The security benefits of a forking server having a re-inialized PRNG in
every child process are pretty obvious. However, due to libraries
having all kinds of internal state, and programs getting compiled with
many different versions of each library, it is unreasonable to expect
calling programs to re-initialize everything manually after fork.
A further complication is the proliferation of clone flags, programs
bypassing glibc's functions to call clone directly, and programs calling
unshare, causing the glibc pthread_atfork hook to not get called.
It would be better to have the kernel take care of this automatically.
The patch also adds MADV_KEEPONFORK, to undo the effects of a prior
MADV_WIPEONFORK.
This is similar to the OpenBSD minherit syscall with MAP_INHERIT_ZERO:
https://man.openbsd.org/minherit.2
[akpm@linux-foundation.org: numerically order arch/parisc/include/uapi/asm/mman.h #defines]
Link: http://lkml.kernel.org/r/20170811212829.29186-3-riel@redhat.com
Signed-off-by: Rik van Riel <riel@redhat.com>
Reported-by: Florian Weimer <fweimer@redhat.com>
Reported-by: Colm MacCártaigh <colm@allcosts.net>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Cc: <linux-api@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Huge page helps to reduce TLB miss rate, but it has higher cache
footprint, sometimes this may cause some issue. For example, when
clearing huge page on x86_64 platform, the cache footprint is 2M. But
on a Xeon E5 v3 2699 CPU, there are 18 cores, 36 threads, and only 45M
LLC (last level cache). That is, in average, there are 2.5M LLC for
each core and 1.25M LLC for each thread.
If the cache pressure is heavy when clearing the huge page, and we clear
the huge page from the begin to the end, it is possible that the begin
of huge page is evicted from the cache after we finishing clearing the
end of the huge page. And it is possible for the application to access
the begin of the huge page after clearing the huge page.
To help the above situation, in this patch, when we clear a huge page,
the order to clear sub-pages is changed. In quite some situation, we
can get the address that the application will access after we clear the
huge page, for example, in a page fault handler. Instead of clearing
the huge page from begin to end, we will clear the sub-pages farthest
from the the sub-page to access firstly, and clear the sub-page to
access last. This will make the sub-page to access most cache-hot and
sub-pages around it more cache-hot too. If we cannot know the address
the application will access, the begin of the huge page is assumed to be
the the address the application will access.
With this patch, the throughput increases ~28.3% in vm-scalability
anon-w-seq test case with 72 processes on a 2 socket Xeon E5 v3 2699
system (36 cores, 72 threads). The test case creates 72 processes, each
process mmap a big anonymous memory area and writes to it from the begin
to the end. For each process, other processes could be seen as other
workload which generates heavy cache pressure. At the same time, the
cache miss rate reduced from ~33.4% to ~31.7%, the IPC (instruction per
cycle) increased from 0.56 to 0.74, and the time spent in user space is
reduced ~7.9%
Christopher Lameter suggests to clear bytes inside a sub-page from end
to begin too. But tests show no visible performance difference in the
tests. May because the size of page is small compared with the cache
size.
Thanks Andi Kleen to propose to use address to access to determine the
order of sub-pages to clear.
The hugetlbfs access address could be improved, will do that in another
patch.
[ying.huang@intel.com: improve readability of clear_huge_page()]
Link: http://lkml.kernel.org/r/20170830051842.1397-1-ying.huang@intel.com
Link: http://lkml.kernel.org/r/20170815014618.15842-1-ying.huang@intel.com
Suggested-by: Andi Kleen <andi.kleen@intel.com>
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Jan Kara <jack@suse.cz>
Reviewed-by: Michal Hocko <mhocko@suse.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Nadia Yvette Chambers <nyc@holomorphy.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Shaohua Li <shli@fb.com>
Cc: Christopher Lameter <cl@linux.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is purely required because exit_aio() may block and exit_mmap() may
never start, if the oom_reap_task cannot start running on a mm with
mm_users == 0.
At the same time if the OOM reaper doesn't wait at all for the memory of
the current OOM candidate to be freed by exit_mmap->unmap_vmas, it would
generate a spurious OOM kill.
If it wasn't because of the exit_aio or similar blocking functions in
the last mmput, it would be enough to change the oom_reap_task() in the
case it finds mm_users == 0, to wait for a timeout or to wait for
__mmput to set MMF_OOM_SKIP itself, but it's not just exit_mmap the
problem here so the concurrency of exit_mmap and oom_reap_task is
apparently warranted.
It's a non standard runtime, exit_mmap() runs without mmap_sem, and
oom_reap_task runs with the mmap_sem for reading as usual (kind of
MADV_DONTNEED).
The race between the two is solved with a combination of
tsk_is_oom_victim() (serialized by task_lock) and MMF_OOM_SKIP
(serialized by a dummy down_write/up_write cycle on the same lines of
the ksm_exit method).
If the oom_reap_task() may be running concurrently during exit_mmap,
exit_mmap will wait it to finish in down_write (before taking down mm
structures that would make the oom_reap_task fail with use after free).
If exit_mmap comes first, oom_reap_task() will skip the mm if
MMF_OOM_SKIP is already set and in turn all memory is already freed and
furthermore the mm data structures may already have been taken down by
free_pgtables.
[aarcange@redhat.com: incremental one liner]
Link: http://lkml.kernel.org/r/20170726164319.GC29716@redhat.com
[rientjes@google.com: remove unused mmput_async]
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1708141733130.50317@chino.kir.corp.google.com
[aarcange@redhat.com: microoptimization]
Link: http://lkml.kernel.org/r/20170817171240.GB5066@redhat.com
Link: http://lkml.kernel.org/r/20170726162912.GA29716@redhat.com
Fixes: 26db62f179 ("oom: keep mm of the killed task available")
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: David Rientjes <rientjes@google.com>
Tested-by: David Rientjes <rientjes@google.com>
Reviewed-by: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If the system has more than one swap device and swap device has the node
information, we can make use of this information to decide which swap
device to use in get_swap_pages() to get better performance.
The current code uses a priority based list, swap_avail_list, to decide
which swap device to use and if multiple swap devices share the same
priority, they are used round robin. This patch changes the previous
single global swap_avail_list into a per-numa-node list, i.e. for each
numa node, it sees its own priority based list of available swap
devices. Swap device's priority can be promoted on its matching node's
swap_avail_list.
The current swap device's priority is set as: user can set a >=0 value,
or the system will pick one starting from -1 then downwards. The
priority value in the swap_avail_list is the negated value of the swap
device's due to plist being sorted from low to high. The new policy
doesn't change the semantics for priority >=0 cases, the previous
starting from -1 then downwards now becomes starting from -2 then
downwards and -1 is reserved as the promoted value.
Take 4-node EX machine as an example, suppose 4 swap devices are
available, each sit on a different node:
swapA on node 0
swapB on node 1
swapC on node 2
swapD on node 3
After they are all swapped on in the sequence of ABCD.
Current behaviour:
their priorities will be:
swapA: -1
swapB: -2
swapC: -3
swapD: -4
And their position in the global swap_avail_list will be:
swapA -> swapB -> swapC -> swapD
prio:1 prio:2 prio:3 prio:4
New behaviour:
their priorities will be(note that -1 is skipped):
swapA: -2
swapB: -3
swapC: -4
swapD: -5
And their positions in the 4 swap_avail_lists[nid] will be:
swap_avail_lists[0]: /* node 0's available swap device list */
swapA -> swapB -> swapC -> swapD
prio:1 prio:3 prio:4 prio:5
swap_avali_lists[1]: /* node 1's available swap device list */
swapB -> swapA -> swapC -> swapD
prio:1 prio:2 prio:4 prio:5
swap_avail_lists[2]: /* node 2's available swap device list */
swapC -> swapA -> swapB -> swapD
prio:1 prio:2 prio:3 prio:5
swap_avail_lists[3]: /* node 3's available swap device list */
swapD -> swapA -> swapB -> swapC
prio:1 prio:2 prio:3 prio:4
To see the effect of the patch, a test that starts N process, each mmap
a region of anonymous memory and then continually write to it at random
position to trigger both swap in and out is used.
On a 2 node Skylake EP machine with 64GiB memory, two 170GB SSD drives
are used as swap devices with each attached to a different node, the
result is:
runtime=30m/processes=32/total test size=128G/each process mmap region=4G
kernel throughput
vanilla 13306
auto-binding 15169 +14%
runtime=30m/processes=64/total test size=128G/each process mmap region=2G
kernel throughput
vanilla 11885
auto-binding 14879 +25%
[aaron.lu@intel.com: v2]
Link: http://lkml.kernel.org/r/20170814053130.GD2369@aaronlu.sh.intel.com
Link: http://lkml.kernel.org/r/20170816024439.GA10925@aaronlu.sh.intel.com
[akpm@linux-foundation.org: use kmalloc_array()]
Link: http://lkml.kernel.org/r/20170814053130.GD2369@aaronlu.sh.intel.com
Link: http://lkml.kernel.org/r/20170816024439.GA10925@aaronlu.sh.intel.com
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Cc: "Chen, Tim C" <tim.c.chen@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
TIF_MEMDIE is set only to the tasks whick were either directly selected
by the OOM killer or passed through mark_oom_victim from the allocator
path. tsk_is_oom_victim is more generic and allows to identify all
tasks (threads) which share the mm with the oom victim.
Please note that the freezer still needs to check TIF_MEMDIE because we
cannot thaw tasks which do not participage in oom_victims counting
otherwise a !TIF_MEMDIE task could interfere after oom_disbale returns.
Link: http://lkml.kernel.org/r/20170810075019.28998-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For ages we have been relying on TIF_MEMDIE thread flag to mark OOM
victims and then, among other things, to give these threads full access
to memory reserves. There are few shortcomings of this implementation,
though.
First of all and the most serious one is that the full access to memory
reserves is quite dangerous because we leave no safety room for the
system to operate and potentially do last emergency steps to move on.
Secondly this flag is per task_struct while the OOM killer operates on
mm_struct granularity so all processes sharing the given mm are killed.
Giving the full access to all these task_structs could lead to a quick
memory reserves depletion. We have tried to reduce this risk by giving
TIF_MEMDIE only to the main thread and the currently allocating task but
that doesn't really solve this problem while it surely opens up a room
for corner cases - e.g. GFP_NO{FS,IO} requests might loop inside the
allocator without access to memory reserves because a particular thread
was not the group leader.
Now that we have the oom reaper and that all oom victims are reapable
after 1b51e65eab ("oom, oom_reaper: allow to reap mm shared by the
kthreads") we can be more conservative and grant only partial access to
memory reserves because there are reasonable chances of the parallel
memory freeing. We still want some access to reserves because we do not
want other consumers to eat up the victim's freed memory. oom victims
will still contend with __GFP_HIGH users but those shouldn't be so
aggressive to starve oom victims completely.
Introduce ALLOC_OOM flag and give all tsk_is_oom_victim tasks access to
the half of the reserves. This makes the access to reserves independent
on which task has passed through mark_oom_victim. Also drop any usage
of TIF_MEMDIE from the page allocator proper and replace it by
tsk_is_oom_victim as well which will make page_alloc.c completely
TIF_MEMDIE free finally.
CONFIG_MMU=n doesn't have oom reaper so let's stick to the original
ALLOC_NO_WATERMARKS approach.
There is a demand to make the oom killer memcg aware which will imply
many tasks killed at once. This change will allow such a usecase
without worrying about complete memory reserves depletion.
Link: http://lkml.kernel.org/r/20170810075019.28998-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's been noted that z3fold doesn't scale well when it's run in a large
number of threads on many cores, which can be easily reproduced with fio
'randrw' test with --numjobs=32. E.g. the result for 1 cluster (4 cores)
is:
Run status group 0 (all jobs):
READ: io=244785MB, aggrb=496883KB/s, minb=15527KB/s, ...
WRITE: io=246735MB, aggrb=500841KB/s, minb=15651KB/s, ...
While for 8 cores (2 clusters) the result is:
Run status group 0 (all jobs):
READ: io=244785MB, aggrb=265942KB/s, minb=8310KB/s, ...
WRITE: io=246735MB, aggrb=268060KB/s, minb=8376KB/s, ...
The bottleneck here is the pool lock which many threads become waiting
upon. To reduce that spin lock contention, z3fold can operate only on
the lists local to the current CPU whenever possible. Due to the nature
of z3fold unbuddied list handling (it only takes the first entry off the
list on a hot path), if the z3fold pool is big enough and balanced well
enough, limiting search to only local unbuddied list doesn't lead to a
significant compression ratio degrade (2.57x vs 2.65x in our
measurements).
This patch also introduces two worker threads: one for async in-page
object layout optimization and one for releasing freed pages. This is
done to speed up z3fold_free() which is often on a hot path.
The fio results for 8-core case are now the following:
Run status group 0 (all jobs):
READ: io=244785MB, aggrb=1568.3MB/s, minb=50182KB/s, ...
WRITE: io=246735MB, aggrb=1580.8MB/s, minb=50582KB/s, ...
So we're in for almost 6x performance increase.
Link: http://lkml.kernel.org/r/20170806181443.f9b65018f8bde25ef990f9e8@gmail.com
Signed-off-by: Vitaly Wool <vitalywool@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
VMA based swap readahead will readahead the virtual pages that is
continuous in the virtual address space. While the original swap
readahead will readahead the swap slots that is continuous in the swap
device. Although VMA based swap readahead is more correct for the swap
slots to be readahead, it will trigger more small random readings, which
may cause the performance of HDD (hard disk) to degrade heavily, and may
finally exceed the benefit.
To avoid the issue, in this patch, if the HDD is used as swap, the VMA
based swap readahead will be disabled, and the original swap readahead
will be used instead.
Link: http://lkml.kernel.org/r/20170807054038.1843-6-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The sysfs interface to control the VMA based swap readahead is added as
follow,
/sys/kernel/mm/swap/vma_ra_enabled
Enable the VMA based swap readahead algorithm, or use the original
global swap readahead algorithm.
/sys/kernel/mm/swap/vma_ra_max_order
Set the max order of the readahead window size for the VMA based swap
readahead algorithm.
The corresponding ABI documentation is added too.
Link: http://lkml.kernel.org/r/20170807054038.1843-5-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The swap readahead is an important mechanism to reduce the swap in
latency. Although pure sequential memory access pattern isn't very
popular for anonymous memory, the space locality is still considered
valid.
In the original swap readahead implementation, the consecutive blocks in
swap device are readahead based on the global space locality estimation.
But the consecutive blocks in swap device just reflect the order of page
reclaiming, don't necessarily reflect the access pattern in virtual
memory. And the different tasks in the system may have different access
patterns, which makes the global space locality estimation incorrect.
In this patch, when page fault occurs, the virtual pages near the fault
address will be readahead instead of the swap slots near the fault swap
slot in swap device. This avoid to readahead the unrelated swap slots.
At the same time, the swap readahead is changed to work on per-VMA from
globally. So that the different access patterns of the different VMAs
could be distinguished, and the different readahead policy could be
applied accordingly. The original core readahead detection and scaling
algorithm is reused, because it is an effect algorithm to detect the
space locality.
The test and result is as follow,
Common test condition
=====================
Test Machine: Xeon E5 v3 (2 sockets, 72 threads, 32G RAM) Swap device:
NVMe disk
Micro-benchmark with combined access pattern
============================================
vm-scalability, sequential swap test case, 4 processes to eat 50G
virtual memory space, repeat the sequential memory writing until 300
seconds. The first round writing will trigger swap out, the following
rounds will trigger sequential swap in and out.
At the same time, run vm-scalability random swap test case in
background, 8 processes to eat 30G virtual memory space, repeat the
random memory write until 300 seconds. This will trigger random swap-in
in the background.
This is a combined workload with sequential and random memory accessing
at the same time. The result (for sequential workload) is as follow,
Base Optimized
---- ---------
throughput 345413 KB/s 414029 KB/s (+19.9%)
latency.average 97.14 us 61.06 us (-37.1%)
latency.50th 2 us 1 us
latency.60th 2 us 1 us
latency.70th 98 us 2 us
latency.80th 160 us 2 us
latency.90th 260 us 217 us
latency.95th 346 us 369 us
latency.99th 1.34 ms 1.09 ms
ra_hit% 52.69% 99.98%
The original swap readahead algorithm is confused by the background
random access workload, so readahead hit rate is lower. The VMA-base
readahead algorithm works much better.
Linpack
=======
The test memory size is bigger than RAM to trigger swapping.
Base Optimized
---- ---------
elapsed_time 393.49 s 329.88 s (-16.2%)
ra_hit% 86.21% 98.82%
The score of base and optimized kernel hasn't visible changes. But the
elapsed time reduced and readahead hit rate improved, so the optimized
kernel runs better for startup and tear down stages. And the absolute
value of readahead hit rate is high, shows that the space locality is
still valid in some practical workloads.
Link: http://lkml.kernel.org/r/20170807054038.1843-4-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In the original implementation, it is possible that the existing pages
in the swap cache (not newly readahead) could be marked as the readahead
pages. This will cause the statistics of swap readahead be wrong and
influence the swap readahead algorithm too.
This is fixed via marking a page as the readahead page only if it is
newly allocated and read from the disk.
When testing with linpack, after the fixing the swap readahead hit rate
increased from ~66% to ~86%.
Link: http://lkml.kernel.org/r/20170807054038.1843-3-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm, swap: VMA based swap readahead", v4.
The swap readahead is an important mechanism to reduce the swap in
latency. Although pure sequential memory access pattern isn't very
popular for anonymous memory, the space locality is still considered
valid.
In the original swap readahead implementation, the consecutive blocks in
swap device are readahead based on the global space locality estimation.
But the consecutive blocks in swap device just reflect the order of page
reclaiming, don't necessarily reflect the access pattern in virtual
memory space. And the different tasks in the system may have different
access patterns, which makes the global space locality estimation
incorrect.
In this patchset, when page fault occurs, the virtual pages near the
fault address will be readahead instead of the swap slots near the fault
swap slot in swap device. This avoid to readahead the unrelated swap
slots. At the same time, the swap readahead is changed to work on
per-VMA from globally. So that the different access patterns of the
different VMAs could be distinguished, and the different readahead
policy could be applied accordingly. The original core readahead
detection and scaling algorithm is reused, because it is an effect
algorithm to detect the space locality.
In addition to the swap readahead changes, some new sysfs interface is
added to show the efficiency of the readahead algorithm and some other
swap statistics.
This new implementation will incur more small random read, on SSD, the
improved correctness of estimation and readahead target should beat the
potential increased overhead, this is also illustrated in the test
results below. But on HDD, the overhead may beat the benefit, so the
original implementation will be used by default.
The test and result is as follow,
Common test condition
=====================
Test Machine: Xeon E5 v3 (2 sockets, 72 threads, 32G RAM)
Swap device: NVMe disk
Micro-benchmark with combined access pattern
============================================
vm-scalability, sequential swap test case, 4 processes to eat 50G
virtual memory space, repeat the sequential memory writing until 300
seconds. The first round writing will trigger swap out, the following
rounds will trigger sequential swap in and out.
At the same time, run vm-scalability random swap test case in
background, 8 processes to eat 30G virtual memory space, repeat the
random memory write until 300 seconds. This will trigger random swap-in
in the background.
This is a combined workload with sequential and random memory accessing
at the same time. The result (for sequential workload) is as follow,
Base Optimized
---- ---------
throughput 345413 KB/s 414029 KB/s (+19.9%)
latency.average 97.14 us 61.06 us (-37.1%)
latency.50th 2 us 1 us
latency.60th 2 us 1 us
latency.70th 98 us 2 us
latency.80th 160 us 2 us
latency.90th 260 us 217 us
latency.95th 346 us 369 us
latency.99th 1.34 ms 1.09 ms
ra_hit% 52.69% 99.98%
The original swap readahead algorithm is confused by the background
random access workload, so readahead hit rate is lower. The VMA-base
readahead algorithm works much better.
Linpack
=======
The test memory size is bigger than RAM to trigger swapping.
Base Optimized
---- ---------
elapsed_time 393.49 s 329.88 s (-16.2%)
ra_hit% 86.21% 98.82%
The score of base and optimized kernel hasn't visible changes. But the
elapsed time reduced and readahead hit rate improved, so the optimized
kernel runs better for startup and tear down stages. And the absolute
value of readahead hit rate is high, shows that the space locality is
still valid in some practical workloads.
This patch (of 5):
The statistics for total readahead pages and total readahead hits are
recorded and exported via the following sysfs interface.
/sys/kernel/mm/swap/ra_hits
/sys/kernel/mm/swap/ra_total
With them, the efficiency of the swap readahead could be measured, so
that the swap readahead algorithm and parameters could be tuned
accordingly.
[akpm@linux-foundation.org: don't display swap stats if CONFIG_SWAP=n]
Link: http://lkml.kernel.org/r/20170807054038.1843-2-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Although llist provides proper APIs, they are not used. Make them used.
Link: http://lkml.kernel.org/r/1502095374-16112-1-git-send-email-byungchul.park@lge.com
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Cc: zijun_hu <zijun_hu@htc.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Comment for pagetypeinfo_showblockcount() is mistakenly duplicated from
pagetypeinfo_show_free()'s comment. This commit fixes it.
Link: http://lkml.kernel.org/r/20170809185816.11244-1-sj38.park@gmail.com
Fixes: 467c996c1e ("Print out statistics in relation to fragmentation avoidance to /proc/pagetypeinfo")
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch came out of discussions in this e-mail thread:
http://lkml.kernel.org/r/1499357846-7481-1-git-send-email-mike.kravetz%40oracle.com
The Oracle JVM team is developing a new garbage collection model. This
new model requires multiple mappings of the same anonymous memory. One
straight forward way to accomplish this is with memfd_create. They can
use the returned fd to create multiple mappings of the same memory.
The JVM today has an option to use (static hugetlb) huge pages. If this
option is specified, they would like to use the same garbage collection
model requiring multiple mappings to the same memory. Using hugetlbfs,
it is possible to explicitly mount a filesystem and specify file paths
in order to get an fd that can be used for multiple mappings. However,
this introduces additional system admin work and coordination.
Ideally they would like to get a hugetlbfs fd without requiring explicit
mounting of a filesystem. Today, mmap and shmget can make use of
hugetlbfs without explicitly mounting a filesystem. The patch adds this
functionality to memfd_create.
Add a new flag MFD_HUGETLB to memfd_create() that will specify the file
to be created resides in the hugetlbfs filesystem. This is the generic
hugetlbfs filesystem not associated with any specific mount point. As
with other system calls that request hugetlbfs backed pages, there is
the ability to encode huge page size in the flag arguments.
hugetlbfs does not support sealing operations, therefore specifying
MFD_ALLOW_SEALING with MFD_HUGETLB will result in EINVAL.
Of course, the memfd_man page would need updating if this type of
functionality moves forward.
Link: http://lkml.kernel.org/r/1502149672-7759-2-git-send-email-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
devm_memremap_pages() records mapped ranges in pgmap_radix with an entry
per section's worth of memory (128MB). The key for each of those
entries is a section number.
This leads to false positives when devm_memremap_pages() is passed a
section-unaligned range as lookups in the misalignment fail to return
NULL. We can close this hole by using the pfn as the key for entries in
the tree. The number of entries required to describe a remapped range
is reduced by leveraging multi-order entries.
In practice this approach usually yields just one entry in the tree if
the size and starting address are of the same power-of-2 alignment.
Previously we always needed nr_entries = mapping_size / 128MB.
Link: https://lists.01.org/pipermail/linux-nvdimm/2016-August/006666.html
Link: http://lkml.kernel.org/r/150215410565.39310.13767886055248249438.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In pcpu_get_vm_areas(), it checks each range is not overlapped. To make
sure it is, only (N^2)/2 comparison is necessary, while current code
does N^2 times. By starting from the next range, it achieves the goal
and the continue could be removed.
Also,
- the overlap check of two ranges could be done with one clause
- one typo in comment is fixed.
Link: http://lkml.kernel.org/r/20170803063822.48702-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When order is -1 or too big, *1UL << order* will be 0, which will cause
a divide error. Although it seems that all callers of
__fragmentation_index() will only do so with a valid order, the patch
can make it more robust.
Should prevent reoccurrences of
https://bugzilla.kernel.org/show_bug.cgi?id=196555
Link: http://lkml.kernel.org/r/1501751520-2598-1-git-send-email-wen.yang99@zte.com.cn
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Reviewed-by: Jiang Biao <jiang.biao2@zte.com.cn>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
alloc_gigantic_page doesn't consider movability of the gigantic hugetlb
when scanning eligible ranges for the allocation. As 1GB hugetlb pages
are not movable currently this can break the movable zone assumption
that all allocations are migrateable and as such break memory hotplug.
Reorganize the code and use the standard zonelist allocations scheme
that we use for standard hugetbl pages. htlb_alloc_mask will ensure
that only migratable hugetlb pages will ever see a movable zone.
Link: http://lkml.kernel.org/r/20170803083549.21407-1-mhocko@kernel.org
Fixes: 944d9fec8d ("hugetlb: add support for gigantic page allocation at runtime")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A __split_vma is not a worthy event to report, and it's definitely not a
unmap so it would be incorrect to report unmap for the whole region to
the userfaultfd manager if a __split_vma fails.
So only call userfaultfd_unmap_prep after the __vma_splitting is over
and do_munmap cannot fail anymore.
Also add unlikely because it's better to optimize for the vast majority
of apps that aren't using userfaultfd in a non cooperative way. Ideally
we should also find a way to eliminate the branch entirely if
CONFIG_USERFAULTFD=n, but it would complicate things so stick to
unlikely for now.
Link: http://lkml.kernel.org/r/20170802165145.22628-5-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Alexey Perevalov <a.perevalov@samsung.com>
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
global_page_state is error prone as a recent bug report pointed out [1].
It only returns proper values for zone based counters as the enum it
gets suggests. We already have global_node_page_state so let's rename
global_page_state to global_zone_page_state to be more explicit here.
All existing users seems to be correct:
$ git grep "global_page_state(NR_" | sed 's@.*(\(NR_[A-Z_]*\)).*@\1@' | sort | uniq -c
2 NR_BOUNCE
2 NR_FREE_CMA_PAGES
11 NR_FREE_PAGES
1 NR_KERNEL_STACK_KB
1 NR_MLOCK
2 NR_PAGETABLE
This patch shouldn't introduce any functional change.
[1] http://lkml.kernel.org/r/201707260628.v6Q6SmaS030814@www262.sakura.ne.jp
Link: http://lkml.kernel.org/r/20170801134256.5400-2-hannes@cmpxchg.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For shmem VMAs we can use shmem_mfill_zeropage_pte for UFFDIO_ZEROPAGE
Link: http://lkml.kernel.org/r/1497939652-16528-6-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Shuffle the code a bit to improve readability.
Link: http://lkml.kernel.org/r/1497939652-16528-5-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
shmem_mfill_zeropage_pte is the low level routine that implements the
userfaultfd UFFDIO_ZEROPAGE command. Since for shmem mappings zero
pages are always allocated and accounted, the new method is a slight
extension of the existing shmem_mcopy_atomic_pte.
Link: http://lkml.kernel.org/r/1497939652-16528-4-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The shmem_acct_block and the update of used_blocks are following one
another in all the places they are used. Combine these two into a
helper function.
Link: http://lkml.kernel.org/r/1497939652-16528-3-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "userfaultfd: enable zeropage support for shmem".
These patches enable support for UFFDIO_ZEROPAGE for shared memory.
The first two patches are not strictly related to userfaultfd, they are
just minor refactoring to reduce amount of code duplication.
This patch (of 7):
Currently we update inode and shmem_inode_info before verifying that
used_blocks will not exceed max_blocks. In case it will, we undo the
update. Let's switch the order and move the verification of the blocks
count before the inode and shmem_inode_info update.
Link: http://lkml.kernel.org/r/1497939652-16528-2-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When swapping out THP (Transparent Huge Page), instead of swapping out
the THP as a whole, sometimes we have to fallback to split the THP into
normal pages before swapping, because no free swap clusters are
available, or cgroup limit is exceeded, etc. To count the number of the
fallback, a new VM event THP_SWPOUT_FALLBACK is added, and counted when
we fallback to split the THP.
Link: http://lkml.kernel.org/r/20170724051840.2309-13-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ross Zwisler <ross.zwisler@intel.com> [for brd.c, zram_drv.c, pmem.c]
Cc: Vishal L Verma <vishal.l.verma@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
