Commit Graph

365163 Commits

Author SHA1 Message Date
Andrew Morton
3ac38faa1f mm/slub.c: use register_hotmemory_notifier()
Squishes a statement-with-no-effect warning, removes some ifdefs and
shrinks .text by 2 bytes.

Note that this code fails to check for blocking_notifier_chain_register()
failures.

Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:36 -07:00
Andrew Morton
8f68fa2d19 ipc/util.c: use register_hotmemory_notifier()
Squishes a statement-with-no-effect warning, removes some ifdefs and
shrinks .text by one byte!

Note that this code fails to check for blocking_notifier_chain_register()
failures.

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:36 -07:00
Andrew Morton
f02c696800 include/linux/memory.h: implement register_hotmemory_notifier()
When CONFIG_MEMORY_HOTPLUG=n, we don't want the memory-hotplug notifier
handlers to be included in the .o files, for space reasons.

The existing hotplug_memory_notifier() tries to handle this but testing
with gcc-4.4.4 shows that it doesn't work - the hotplug functions are
still present in the .o files.

So implement a new register_hotmemory_notifier() which is a copy of
register_hotcpu_notifier(), and which actually works as desired.
hotplug_memory_notifier() and register_memory_notifier() callsites
should be converted to use this new register_hotmemory_notifier().

While we're there, let's repair the existing hotplug_memory_notifier():
it simply stomps on the register_memory_notifier() return value, so
well-behaved code cannot check for errors.  Apparently non of the
existing callers were well-behaved :(

Cc: Andrew Shewmaker <agshew@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:36 -07:00
Cody P Schafer
f9d531b8dc powerpc/mm/numa: use setup_nr_node_ids() instead of opencoding.
[sfr@canb.auug.org.au: add missing semicolon]
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:36 -07:00
Cody P Schafer
d2ad351e36 x86/mm/numa: use setup_nr_node_ids() instead of opencoding.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:36 -07:00
Cody P Schafer
f9872caf07 page_alloc: make setup_nr_node_ids() usable for arch init code
powerpc and x86 were opencoding copies of setup_nr_node_ids(), which
page_alloc provides but makes static.  Make it avaliable to the archs in
linux/mm.h.

Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:36 -07:00
Russ Anderson
7c243c7168 mm: speedup in __early_pfn_to_nid
When booting on a large memory system, the kernel spends considerable
time in memmap_init_zone() setting up memory zones.  Analysis shows
significant time spent in __early_pfn_to_nid().

The routine memmap_init_zone() checks each PFN to verify the nid is
valid.  __early_pfn_to_nid() sequentially scans the list of pfn ranges
to find the right range and returns the nid.  This does not scale well.
On a 4 TB (single rack) system there are 308 memory ranges to scan.  The
higher the PFN the more time spent sequentially spinning through memory
ranges.

Since memmap_init_zone() increments pfn, it will almost always be
looking for the same range as the previous pfn, so check that range
first.  If it is in the same range, return that nid.  If not, scan the
list as before.

A 4 TB (single rack) UV1 system takes 512 seconds to get through the
zone code.  This performance optimization reduces the time by 189
seconds, a 36% improvement.

A 2 TB (single rack) UV2 system goes from 212.7 seconds to 99.8 seconds,
a 112.9 second (53%) reduction.

[akpm@linux-foundation.org: make the statics __meminitdata]
[akpm@linux-foundation.org: fix comment formatting]
[akpm@linux-foundation.org: fix ia64, per yinghai]
[akpm@linux-foundation.org: add missing semicolon, per Tony]
Signed-off-by: Russ Anderson <rja@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Tested-by: "Luck, Tony" <tony.luck@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Lin Feng <linfeng@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:35 -07:00
Jianguo Wu
fed5b64a95 mm/migrate: fix comment typo syncronous->synchronous
Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:35 -07:00
Mel Gorman
fed2719e7a mm: page_alloc: avoid marking zones full prematurely after zone_reclaim()
The following problem was reported against a distribution kernel when
zone_reclaim was enabled but the same problem applies to the mainline
kernel.  The reproduction case was as follows

1. Run numactl -m +0 dd if=largefile of=/dev/null
   This allocates a large number of clean pages in node 0

2. numactl -N +0 memhog 0.5*Mg
   This start a memory-using application in node 0.

The expected behaviour is that the clean pages get reclaimed and the
application uses node 0 for its memory.  The observed behaviour was that
the memory for the memhog application was allocated off-node since
commits cd38b115d5 ("mm: page allocator: initialise ZLC for first zone
eligible for zone_reclaim") and commit 76d3fbf8fb ("mm: page
allocator: reconsider zones for allocation after direct reclaim").

The assumption of those patches was that it was always preferable to
allocate quickly than stall for long periods of time and they were meant
to take care that the zone was only marked full when necessary but an
important case was missed.

In the allocator fast path, only the low watermarks are checked.  If the
zones free pages are between the low and min watermark then allocations
from the allocators slow path will succeed.  However, zone_reclaim will
only reclaim SWAP_CLUSTER_MAX or 1<<order pages.  There is no guarantee
that this will meet the low watermark causing the zone to be marked full
prematurely.

This patch will only mark the zone full after zone_reclaim if it the min
watermarks are checked or if page reclaim failed to make sufficient
progress.

[mhocko@suse.cz: fix alloc_flags test]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Hedi Berriche <hedi@sgi.com>
Tested-by: Hedi Berriche <hedi@sgi.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:35 -07:00
Johannes Weiner
8e2cdbcb86 x86-64: fall back to regular page vmemmap on allocation failure
Memory hotplug can happen on a machine under load, memory shortness
and fragmentation, so huge page allocations for the vmemmap are not
guaranteed to succeed.

Try to fall back to regular pages before failing the hotplug event
completely.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Bernhard Schmidt <Bernhard.Schmidt@lrz.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:35 -07:00
Johannes Weiner
e8216da5c7 x86-64: use vmemmap_populate_basepages() for !pse setups
We already have generic code to allocate vmemmap with regular pages, use
it.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Bernhard Schmidt <Bernhard.Schmidt@lrz.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:35 -07:00
Johannes Weiner
6c7a2ca4c1 x86-64: remove dead debugging code for !pse setups
No need to maintain addr_end and p_end when they are never actually read
anywhere on !pse setups.  Remove the dead code.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Bernhard Schmidt <Bernhard.Schmidt@lrz.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:35 -07:00
Johannes Weiner
0aad818b2d sparse-vmemmap: specify vmemmap population range in bytes
The sparse code, when asking the architecture to populate the vmemmap,
specifies the section range as a starting page and a number of pages.

This is an awkward interface, because none of the arch-specific code
actually thinks of the range in terms of 'struct page' units and always
translates it to bytes first.

In addition, later patches mix huge page and regular page backing for
the vmemmap.  For this, they need to call vmemmap_populate_basepages()
on sub-section ranges with PAGE_SIZE and PMD_SIZE in mind.  But these
are not necessarily multiples of the 'struct page' size and so this unit
is too coarse.

Just translate the section range into bytes once in the generic sparse
code, then pass byte ranges down the stack.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Bernhard Schmidt <Bernhard.Schmidt@lrz.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: David S. Miller <davem@davemloft.net>
Tested-by: David S. Miller <davem@davemloft.net>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:35 -07:00
Ben Hutchings
055e4fd96e mm: try harder to allocate vmemmap blocks
Hot-adding memory on x86_64 normally requires huge page allocation.
When this is done to a VM guest, it's usually because the system is
already tight on memory, so the request tends to fail.  Try to avoid
this by adding __GFP_REPEAT to the allocation flags.

Addresses http://bugs.debian.org/699913

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Bernhard Schmidt <Bernhard.Schmidt@lrz.de>
Tested-by: Bernhard Schmidt <Bernhard.Schmidt@lrz.de>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:35 -07:00
David Rientjes
949f7ec576 mm, hugetlb: include hugepages in meminfo
Particularly in oom conditions, it's troublesome that hugetlb memory is
not displayed.  All other meminfo that is emitted will not add up to
what is expected, and there is no artifact left in the kernel log to
show that a potentially significant amount of memory is actually
allocated as hugepages which are not available to be reclaimed.

Booting with hugepages=8192 on the command line, this memory is now
shown in oom conditions.  For example, with echo m >
/proc/sysrq-trigger:

  Node 0 hugepages_total=2048 hugepages_free=2048 hugepages_surp=0 hugepages_size=2048kB
  Node 1 hugepages_total=2048 hugepages_free=2048 hugepages_surp=0 hugepages_size=2048kB
  Node 2 hugepages_total=2048 hugepages_free=2048 hugepages_surp=0 hugepages_size=2048kB
  Node 3 hugepages_total=2048 hugepages_free=2048 hugepages_surp=0 hugepages_size=2048kB

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:35 -07:00
Hampson, Steven T
1444f92c84 mm: merging memory blocks resets mempolicy
Using mbind to change the mempolicy to MPOL_BIND on several adjacent
mmapped blocks may result in a reset of the mempolicy to MPOL_DEFAULT in
vma_adjust.

Test code.  Correct result is three lines containing "OK".

#include <stdio.h>
#include <unistd.h>
#include <sys/mman.h>
#include <numaif.h>
#include <errno.h>

/* gcc mbind_test.c -lnuma -o mbind_test -Wall */
#define MAXNODE 4096

void allocate()
{
	int ret;
	int len;
	int policy = -1;
	unsigned char *p;
	unsigned long mask[MAXNODE] = { 0 };
	unsigned long retmask[MAXNODE] = { 0 };

	len = getpagesize() * 0x2fc00;
	p = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
		 -1, 0);
	if (p == MAP_FAILED)
		printf("mbind err: %d\n", errno);

	mask[0] = 1;
	ret = mbind(p, len, MPOL_BIND, mask, MAXNODE, 0);
	if (ret < 0)
		printf("mbind err: %d %d\n", ret, errno);
	ret = get_mempolicy(&policy, retmask, MAXNODE, p, MPOL_F_ADDR);
	if (ret < 0)
		printf("get_mempolicy err: %d %d\n", ret, errno);

	if (policy == MPOL_BIND)
		printf("OK\n");
	else
		printf("ERROR: policy is %d\n", policy);
}

int main()
{
	allocate();
	allocate();
	allocate();
	return 0;
}

Signed-off-by: Steven T Hampson <steven.t.hampson@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:35 -07:00
Catalin Marinas
104ad3b32d arm: set the page table freeing ceiling to TASK_SIZE
ARM processors with LPAE enabled use 3 levels of page tables, with an
entry in the top level (pgd) covering 1GB of virtual space.  Because of
the branch relocation limitations on ARM, the loadable modules are
mapped 16MB below PAGE_OFFSET, making the corresponding 1GB pgd shared
between kernel modules and user space.

If free_pgtables() is called with the default ceiling 0,
free_pgd_range() (and subsequently called functions) also frees the page
table shared between user space and kernel modules (which is normally
handled by the ARM-specific pgd_free() function).  This patch changes
defines the ARM USER_PGTABLES_CEILING to TASK_SIZE when CONFIG_ARM_LPAE
is enabled.

Note that the pgd_free() function already checks the presence of the
shared pmd page allocated by pgd_alloc() and frees it, though with
ceiling 0 this wasn't necessary.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>	[3.3+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:34 -07:00
Hugh Dickins
6ee8630e02 mm: allow arch code to control the user page table ceiling
On architectures where a pgd entry may be shared between user and kernel
(e.g.  ARM+LPAE), freeing page tables needs a ceiling other than 0.
This patch introduces a generic USER_PGTABLES_CEILING that arch code can
override.  It is the responsibility of the arch code setting the ceiling
to ensure the complete freeing of the page tables (usually in
pgd_free()).

[catalin.marinas@arm.com: commit log; shift_arg_pages(), asm-generic/pgtables.h changes]
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: <stable@vger.kernel.org>	[3.3+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:34 -07:00
Michal Hocko
acb6d558f4 memcg: do not check for do_swap_account in mem_cgroup_{read,write,reset}
Since commit 2d11085e40 ("memcg: do not create memsw files if swap
accounting is disabled") memsw files are created only if memcg swap
accounting is enabled so it doesn't make any sense to check for it
explicitly in mem_cgroup_read(), mem_cgroup_write() and
mem_cgroup_reset().

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:34 -07:00
Zhang Yanfei
ee5df0570c mmap: find_vma: remove the WARN_ON_ONCE(!mm) check
Remove the WARN_ON_ONCE(!mm) check as the comment suggested.  Kernel
code calls find_vma only when it is absolutely sure that the mm_struct
arg to it is non-NULL.

Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: k80c <k80ck80c@gmail.com>
Cc: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:34 -07:00
Atsushi Kumagai
13ba3fcbbe kexec, vmalloc: export additional vmalloc layer information
Now, vmap_area_list is exported as VMCOREINFO for makedumpfile to get
the start address of vmalloc region (vmalloc_start).  The address which
contains vmalloc_start value is represented as below:

  vmap_area_list.next - OFFSET(vmap_area.list) + OFFSET(vmap_area.va_start)

However, both OFFSET(vmap_area.va_start) and OFFSET(vmap_area.list)
aren't exported as VMCOREINFO.

So this patch exports them externally with small cleanup.

[akpm@linux-foundation.org: vmalloc.h should include list.h for list_head]
Signed-off-by: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Dave Anderson <anderson@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:34 -07:00
Joonsoo Kim
4341fa4547 mm, vmalloc: remove list management of vmlist after initializing vmalloc
Now, there is no need to maintain vmlist after initializing vmalloc.  So
remove related code and data structure.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Dave Anderson <anderson@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:34 -07:00
Joonsoo Kim
f1c4069e1d mm, vmalloc: export vmap_area_list, instead of vmlist
Although our intention is to unexport internal structure entirely, but
there is one exception for kexec.  kexec dumps address of vmlist and
makedumpfile uses this information.

We are about to remove vmlist, then another way to retrieve information
of vmalloc layer is needed for makedumpfile.  For this purpose, we
export vmap_area_list, instead of vmlist.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Dave Anderson <anderson@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:34 -07:00
Joonsoo Kim
d4033afdf8 mm, vmalloc: iterate vmap_area_list, instead of vmlist, in vmallocinfo()
This patch is a preparatory step for removing vmlist entirely.  For
above purpose, we change iterating a vmap_list codes to iterating a
vmap_area_list.  It is somewhat trivial change, but just one thing
should be noticed.

Using vmap_area_list in vmallocinfo() introduce ordering problem in SMP
system.  In s_show(), we retrieve some values from vm_struct.
vm_struct's values is not fully setup when va->vm is assigned.  Full
setup is notified by removing VM_UNLIST flag without holding a lock.
When we see that VM_UNLIST is removed, it is not ensured that vm_struct
has proper values in view of other CPUs.  So we need smp_[rw]mb for
ensuring that proper values is assigned when we see that VM_UNLIST is
removed.

Therefore, this patch not only change a iteration list, but also add a
appropriate smp_[rw]mb to right places.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Dave Anderson <anderson@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:34 -07:00
Joonsoo Kim
f98782ddd3 mm, vmalloc: iterate vmap_area_list in get_vmalloc_info()
This patch is a preparatory step for removing vmlist entirely.  For
above purpose, we change iterating a vmap_list codes to iterating a
vmap_area_list.  It is somewhat trivial change, but just one thing
should be noticed.

vmlist is lack of information about some areas in vmalloc address space.
For example, vm_map_ram() allocate area in vmalloc address space, but it
doesn't make a link with vmlist.  To provide full information about
vmalloc address space is better idea, so we don't use va->vm and use
vmap_area directly.  This makes get_vmalloc_info() more precise.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Dave Anderson <anderson@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:34 -07:00
Joonsoo Kim
e81ce85f96 mm, vmalloc: iterate vmap_area_list, instead of vmlist in vread/vwrite()
Now, when we hold a vmap_area_lock, va->vm can't be discarded.  So we can
safely access to va->vm when iterating a vmap_area_list with holding a
vmap_area_lock.  With this property, change iterating vmlist codes in
vread/vwrite() to iterating vmap_area_list.

There is a little difference relate to lock, because vmlist_lock is mutex,
but, vmap_area_lock is spin_lock.  It may introduce a spinning overhead
during vread/vwrite() is executing.  But, these are debug-oriented
functions, so this overhead is not real problem for common case.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Dave Anderson <anderson@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:34 -07:00
Joonsoo Kim
c69480adee mm, vmalloc: protect va->vm by vmap_area_lock
Inserting and removing an entry to vmlist is linear time complexity, so
it is inefficient.  Following patches will try to remove vmlist
entirely.  This patch is preparing step for it.

For removing vmlist, iterating vmlist codes should be changed to
iterating a vmap_area_list.  Before implementing that, we should make
sure that when we iterate a vmap_area_list, accessing to va->vm doesn't
cause a race condition.  This patch ensure that when iterating a
vmap_area_list, there is no race condition for accessing to vm_struct.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Dave Anderson <anderson@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:33 -07:00
Joonsoo Kim
db3808c1ba mm, vmalloc: move get_vmalloc_info() to vmalloc.c
Now get_vmalloc_info() is in fs/proc/mmu.c.  There is no reason that this
code must be here and it's implementation needs vmlist_lock and it iterate
a vmlist which may be internal data structure for vmalloc.

It is preferable that vmlist_lock and vmlist is only used in vmalloc.c
for maintainability. So move the code to vmalloc.c

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Dave Anderson <anderson@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:33 -07:00
Joonsoo Kim
ef93247325 mm, vmalloc: change iterating a vmlist to find_vm_area()
This patchset removes vm_struct list management after initializing
vmalloc.  Adding and removing an entry to vmlist is linear time
complexity, so it is inefficient.  If we maintain this list, overall
time complexity of adding and removing area to vmalloc space is O(N),
although we use rbtree for finding vacant place and it's time complexity
is just O(logN).

And vmlist and vmlist_lock is used many places of outside of vmalloc.c.
It is preferable that we hide this raw data structure and provide
well-defined function for supporting them, because it makes that they
cannot mistake when manipulating theses structure and it makes us easily
maintain vmalloc layer.

For kexec and makedumpfile, I export vmap_area_list, instead of vmlist.
This comes from Atsushi's recommendation.  For more information, please
refer below link.  https://lkml.org/lkml/2012/12/6/184

This patch:

The purpose of iterating a vmlist is finding vm area with specific virtual
address.  find_vm_area() is provided for this purpose and more efficient,
because it uses a rbtree.  So change it.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Dave Anderson <anderson@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:33 -07:00
Darrick J. Wong
7136851117 mm: make snapshotting pages for stable writes a per-bio operation
Walking a bio's page mappings has proved problematic, so create a new
bio flag to indicate that a bio's data needs to be snapshotted in order
to guarantee stable pages during writeback.  Next, for the one user
(ext3/jbd) of snapshotting, hook all the places where writes can be
initiated without PG_writeback set, and set BIO_SNAP_STABLE there.

We must also flag journal "metadata" bios for stable writeout, since
file data can be written through the journal.  Finally, the
MS_SNAP_STABLE mount flag (only used by ext3) is now superfluous, so get
rid of it.

[akpm@linux-foundation.org: rename _submit_bh()'s `flags' to `bio_flags', delobotomize the _submit_bh declaration]
[akpm@linux-foundation.org: teeny cleanup]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:33 -07:00
Gerald Schaefer
106c992a5e mm/hugetlb: add more arch-defined huge_pte functions
Commit abf09bed3c ("s390/mm: implement software dirty bits")
introduced another difference in the pte layout vs.  the pmd layout on
s390, thoroughly breaking the s390 support for hugetlbfs.  This requires
replacing some more pte_xxx functions in mm/hugetlbfs.c with a
huge_pte_xxx version.

This patch introduces those huge_pte_xxx functions and their generic
implementation in asm-generic/hugetlb.h, which will now be included on
all architectures supporting hugetlbfs apart from s390.  This change
will be a no-op for those architectures.

[akpm@linux-foundation.org: fix warning]
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Hillf Danton <dhillf@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.cz>	[for !s390 parts]
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:33 -07:00
Josh Triplett
146732ce10 fs: don't compile in drop_caches.c when CONFIG_SYSCTL=n
drop_caches.c provides code only invokable via sysctl, so don't compile it
in when CONFIG_SYSCTL=n.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:33 -07:00
Michal Hocko
6d2488f64a cgroup: remove css_get_next
Now that we have generic and well ordered cgroup tree walkers there is
no need to keep css_get_next in the place.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ying Han <yinghan@google.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:33 -07:00
Michal Hocko
16248d8fe6 memcg: further simplify mem_cgroup_iter
mem_cgroup_iter basically does two things currently.  It takes care of
the house keeping (reference counting, raclaim cookie) and it iterates
through a hierarchy tree (by using cgroup generic tree walk).  The code
would be much more easier to follow if we move the iteration outside of
the function (to __mem_cgrou_iter_next) so the distinction is more
clear.  This patch doesn't introduce any functional changes.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Ying Han <yinghan@google.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:33 -07:00
Michal Hocko
19f3940286 memcg: simplify mem_cgroup_iter
The current implementation of mem_cgroup_iter has to consider both css
and memcg to find out whether no group has been found (css==NULL - aka
the loop is completed) and that no memcg is associated with the found
node (!memcg - aka css_tryget failed because the group is no longer
alive).  This leads to awkward tweaks like tests for css && !memcg to
skip the current node.

It will be much easier if we got rid off css variable altogether and
only rely on memcg.  In order to do that the iteration part has to skip
dead nodes.  This sounds natural to me and as a nice side effect we will
get a simple invariant that memcg is always alive when non-NULL and all
nodes have been visited otherwise.

We could get rid of the surrounding while loop but keep it in for now to
make review easier.  It will go away in the following patch.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Ying Han <yinghan@google.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:33 -07:00
Michal Hocko
5f57816197 memcg: relax memcg iter caching
Now that the per-node-zone-priority iterator caches memory cgroups
rather than their css ids we have to be careful and remove them from the
iterator when they are on the way out otherwise they might live for
unbounded amount of time even though their group is already gone (until
the global/targeted reclaim triggers the zone under priority to find out
the group is dead and let it to find the final rest).

We can fix this issue by relaxing rules for the last_visited memcg.
Instead of taking a reference to the css before it is stored into
iter->last_visited we can just store its pointer and track the number of
removed groups from each memcg's subhierarchy.

This number would be stored into iterator everytime when a memcg is
cached.  If the iter count doesn't match the curent walker root's one we
will start from the root again.  The group counter is incremented
upwards the hierarchy every time a group is removed.

The iter_lock can be dropped because racing iterators cannot leak the
reference anymore as the reference count is not elevated for
last_visited when it is cached.

Locking rules got a bit complicated by this change though.  The iterator
primarily relies on rcu read lock which makes sure that once we see a
valid last_visited pointer then it will be valid for the whole RCU walk.
smp_rmb makes sure that dead_count is read before last_visited and
last_dead_count while smp_wmb makes sure that last_visited is updated
before last_dead_count so the up-to-date last_dead_count cannot point to
an outdated last_visited.  css_tryget then makes sure that the
last_visited is still alive in case the iteration races with the cached
group removal (css is invalidated before mem_cgroup_css_offline
increments dead_count).

In short:
mem_cgroup_iter
 rcu_read_lock()
 dead_count = atomic_read(parent->dead_count)
 smp_rmb()
 if (dead_count != iter->last_dead_count)
 	last_visited POSSIBLY INVALID -> last_visited = NULL
 if (!css_tryget(iter->last_visited))
 	last_visited DEAD -> last_visited = NULL
 next = find_next(last_visited)
 css_tryget(next)
 css_put(last_visited) 	// css would be invalidated and parent->dead_count
 			// incremented if this was the last reference
 iter->last_visited = next
 smp_wmb()
 iter->last_dead_count = dead_count
 rcu_read_unlock()

cgroup_rmdir
 cgroup_destroy_locked
  atomic_add(CSS_DEACT_BIAS, &css->refcnt) // subsequent css_tryget fail
   mem_cgroup_css_offline
    mem_cgroup_invalidate_reclaim_iterators
     while(parent = parent_mem_cgroup)
     	atomic_inc(parent->dead_count)
  css_put(css) // last reference held by cgroup core

Spotted by Ying Han.

Original idea from Johannes Weiner.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ying Han <yinghan@google.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:32 -07:00
Michal Hocko
542f85f9ae memcg: rework mem_cgroup_iter to use cgroup iterators
mem_cgroup_iter curently relies on css->id when walking down a group
hierarchy tree.  This is really awkward because the tree walk depends on
the groups creation ordering.  The only guarantee is that a parent node is
visited before its children.

Example:

 1) mkdir -p a a/d a/b/c
 2) mkdir -a a/b/c a/d

Will create the same trees but the tree walks will be different:

 1) a, d, b, c
 2) a, b, c, d

Commit 574bd9f7c7 ("cgroup: implement generic child / descendant walk
macros") has introduced generic cgroup tree walkers which provide either
pre-order or post-order tree walk.  This patch converts css->id based
iteration to pre-order tree walk to keep the semantic with the original
iterator where parent is always visited before its subtree.

cgroup_for_each_descendant_pre suggests using post_create and
pre_destroy for proper synchronization with groups addidition resp.
removal.  This implementation doesn't use those because a new memory
cgroup is initialized sufficiently for iteration in mem_cgroup_css_alloc
already and css reference counting enforces that the group is alive for
both the last seen cgroup and the found one resp.  it signals that the
group is dead and it should be skipped.

If the reclaim cookie is used we need to store the last visited group
into the iterator so we have to be careful that it doesn't disappear in
the mean time.  Elevated reference count on the css keeps it alive even
though the group have been removed (parked waiting for the last dput so
that it can be freed).

Per node-zone-prio iter_lock has been introduced to ensure that
css_tryget and iter->last_visited is set atomically.  Otherwise two
racing walkers could both take a references and only one release it
leading to a css leak (which pins cgroup dentry).

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Ying Han <yinghan@google.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:32 -07:00
Michal Hocko
c40046f3ad memcg: keep prev's css alive for the whole mem_cgroup_iter
The patchset tries to make mem_cgroup_iter saner in the way how it walks
hierarchies.  css->id based traversal is far from being ideal as it is not
deterministic because it depends on the creation ordering.  Additional to
that css_id is considered a burden for cgroup maintainers because it is
quite some code and memcg is the last user of it.  After this series only
the swap accounting uses css_id but that one will follow up later.

Diffstat (if we exclude removed/added comments) looks quite
promising. We got rid of some code:

  $ git diff mmotm... | grep -v "^[+-][[:space:]]*[/ ]\*" | diffstat
   b/include/linux/cgroup.h |    3 ---
   kernel/cgroup.c          |   33 ---------------------------------
   mm/memcontrol.c          |    4 +++-
   3 files changed, 3 insertions(+), 37 deletions(-)

The first patch is just preparatory and it changes when we release css of
the previously returned memcg.  Nothing controlversial.

The second patch is the core of the patchset and it replaces css_get_next
based on css_id by the generic cgroup pre-order.  This brings some
chalanges for the last visited group caching during the reclaim
(mem_cgroup_per_zone::reclaim_iter).  We have to use memcg pointers
directly now which means that we have to keep a reference to those groups'
css to keep them alive.

I also folded iter_lock introduced by https://lkml.org/lkml/2013/1/3/295
in the previous version into this patch.  Johannes felt the race I was
describing should be mostly harmless and I haven't been able to trigger it
so the lock doesn't deserve its own patch.  It is still needed
temporarily, though, because the reference counting on iter->last_visited
depends on it.  It will go away with the next patch.

The next patch fixups an unbounded cgroup removal holdoff caused by the
elevated css refcount.  The issue has been observed by Ying Han.  Johannes
wasn't impressed by the previous version of the fix
(https://lkml.org/lkml/2013/2/8/379) which cleaned up pending references
during mem_cgroup_css_offline when a group is removed.  He has suggested a
different way when the iterator checks whether a cached memcg is still
valid or no.  More on that in the patch but the basic idea is that every
memcg tracks the number removed subgroups and iterator records this number
when a group is cached.  These numbers are checked before
iter->last_visited is about to be used and the iteration is restarted if
it is invalid.

The fourth and fifth patches are an attempt for simplification of the
mem_cgroup_iter.  css juggling is removed and the iteration logic is moved
to a helper so that the reference counting and iteration are separated.

The last patch just removes css_get_next as there is no user for it any
longer.

My testing looked as follows:
        A (use_hierarchy=1, limit_in_bytes=150M)
       /|\
      1 2 3

Children groups were created so that the number is never higher than 3 and
their limits were random between 50-100M.  Each group hosts a kernel build
(starting with tar -xf so the tree is not shared and make -jNUM_CPUs/3)
and terminated after random time - up to 5 minutes) and then it is
removed.

This should exercise both leaf and hierarchical reclaim as well as races
with cgroup removals and debugging messages I added on top proved that.
100 groups were created during the test.

This patch:

css reference counting keeps the cgroup alive even though it has been
already removed.  mem_cgroup_iter relies on this fact and takes a
reference to the returned group.  The reference is then released on the
next iteration or mem_cgroup_iter_break.  mem_cgroup_iter currently
releases the reference right after it gets the last css_id.

This is correct because neither prev's memcg nor cgroup are accessed after
then.  This will change in the next patch so we need to hold the group
alive a bit longer so let's move the css_put at the end of the function.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Ying Han <yinghan@google.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:32 -07:00
Jiang Liu
5e7ccf8635 mm/x86: use free_highmem_page() to free highmem pages into buddy system
Use helper function free_highmem_page() to free highmem pages into
the buddy system.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Cong Wang <amwang@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Attilio Rao <attilio.rao@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:32 -07:00
Jiang Liu
5b472b2057 mm/um: use free_highmem_page() to free highmem pages into buddy system
Use helper function free_highmem_page() to free highmem pages into
the buddy system.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:32 -07:00
Jiang Liu
32e1a10927 mm/SPARC: use free_highmem_page() to free highmem pages into buddy system
Use helper function free_highmem_page() to free highmem pages into
the buddy system.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: "David S. Miller" <davem@davemloft.net>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:32 -07:00
Jiang Liu
7db6f78cfe mm/PPC: use free_highmem_page() to free highmem pages into buddy system
Use helper function free_highmem_page() to free highmem pages into
the buddy system.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: "Suzuki K. Poulose" <suzuki@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:32 -07:00
Jiang Liu
0f354869e3 mm/MIPS: use free_highmem_page() to free highmem pages into buddy system
Use helper function free_highmem_page() to free highmem pages into
the buddy system.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <david.daney@cavium.com>
Cc: Cong Wang <amwang@redhat.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>
2013-04-29 15:54:32 -07:00
Jiang Liu
ec601a34f5 mm/microblaze: use free_highmem_page() to free highmem pages into buddy system
Use helper function free_highmem_page() to free highmem pages into
the buddy system.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Michal Simek <monstr@monstr.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:32 -07:00
Jiang Liu
a564496e2c mm/metag: use free_highmem_page() to free highmem pages into buddy system
Use helper function free_highmem_page() to free highmem pages into
the buddy system.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:32 -07:00
Jiang Liu
8b2888c756 mm/FRV: use free_highmem_page() to free highmem pages into buddy system
Use helper function free_highmem_page() to free highmem pages into
the buddy system.

Also fix a bug that totalhigh_pages should be increased when freeing
a highmem page into the buddy system.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:32 -07:00
Jiang Liu
dd6911efb5 mm/ARM: use free_highmem_page() to free highmem pages into buddy system
Use helper function free_highmem_page() to free highmem pages into
the buddy system.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:31 -07:00
Jiang Liu
cfa11e08ed mm: introduce free_highmem_page() helper to free highmem pages into buddy system
The original goal of this patchset is to fix the bug reported by

  https://bugzilla.kernel.org/show_bug.cgi?id=53501

Now it has also been expanded to reduce common code used by memory
initializion.

This is the second part, which applies to the previous part at:
  http://marc.info/?l=linux-mm&m=136289696323825&w=2

It introduces a helper function free_highmem_page() to free highmem
pages into the buddy system when initializing mm subsystem.
Introduction of free_highmem_page() is one step forward to clean up
accesses and modificaitons of totalhigh_pages, totalram_pages and
zone->managed_pages etc. I hope we could remove all references to
totalhigh_pages from the arch/ subdirectory.

We have only tested these patchset on x86 platforms, and have done basic
compliation tests using cross-compilers from ftp.kernel.org. That means
some code may not pass compilation on some architectures. So any help
to test this patchset are welcomed!

There are several other parts still under development:
Part3: refine code to manage totalram_pages, totalhigh_pages and
	zone->managed_pages
Part4: introduce helper functions to simplify mem_init() and remove the
	global variable num_physpages.

This patch:

Introduce helper function free_highmem_page(), which will be used by
architectures with HIGHMEM enabled to free highmem pages into the buddy
system.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Suzuki K. Poulose" <suzuki@in.ibm.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Attilio Rao <attilio.rao@citrix.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Cong Wang <amwang@redhat.com>
Cc: David Daney <david.daney@cavium.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Michel Lespinasse <walken@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rik van Riel <riel@redhat.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:31 -07:00
Jiang Liu
e07cee23e6 mm,kexec: use common help functions to free reserved pages
Use common help functions to free reserved pages.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:31 -07:00
Jiang Liu
c941836819 mm/metag: use common help functions to free reserved pages
Use common help functions to free reserved pages.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:31 -07:00