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6f8c00ff5a
947556 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Arvind Sankar
|
6f8c00ff5a |
sparc: drop unused MAX_PHYSADDR_BITS
The macro is not used anywhere, so remove the definition. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Link: http://lkml.kernel.org/r/20200723231544.17274-4-nivedita@alum.mit.edu Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Arvind Sankar
|
c56771b309 |
sh/mm: drop unused MAX_PHYSADDR_BITS
The macro is not used anywhere, so remove the definition. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Link: http://lkml.kernel.org/r/20200723231544.17274-3-nivedita@alum.mit.edu Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Randy Dunlap
|
0845f83122 |
include/linux/memcontrol.h: drop duplicate word and fix spello
Drop the doubled word "for" in a comment. Fix spello of "incremented". Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Chris Down <chris@chrisdown.name> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Link: http://lkml.kernel.org/r/b04aa2e4-7c95-12f0-599d-43d07fb28134@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Randy Dunlap
|
c82f16b52c |
include/linux/frontswap.h: drop duplicated word in a comment
Drop the doubled word "in" in a comment. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Link: http://lkml.kernel.org/r/3af7ed91-ad62-8445-40a4-9e07a64b9523@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Randy Dunlap
|
3ecabd3134 |
include/linux/highmem.h: fix duplicated words in a comment
Change the doubled word "is" in a comment to "it is". Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/ad605959-0083-4794-8d31-6b073300dd6f@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Randy Dunlap
|
1119233720 |
mm: drop duplicated words in <linux/mm.h>
Drop the doubled words "to" and "the". Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: SeongJae Park <sjpark@amazon.de> Link: http://lkml.kernel.org/r/d9fae8d6-0d60-4d52-9385-3199ee98de49@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Randy Dunlap
|
1067b261cc |
mm: drop duplicated words in <linux/pgtable.h>
Drop the doubled words "used" and "by". Drop the repeated acronym "TLB" and make several other fixes around it. (capital letters, spellos) Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: SeongJae Park <sjpark@amazon.de> Link: http://lkml.kernel.org/r/2bb6e13e-44df-4920-52d9-4d3539945f73@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Charan Teja Reddy
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de1193f0be |
mm, memory_hotplug: update pcp lists everytime onlining a memory block
When onlining a first memory block in a zone, pcp lists are not updated
thus pcp struct will have the default setting of ->high = 0,->batch = 1.
This means till the second memory block in a zone(if it have) is onlined
the pcp lists of this zone will not contain any pages because pcp's
->count is always greater than ->high thus free_pcppages_bulk() is called
to free batch size(=1) pages every time system wants to add a page to the
pcp list through free_unref_page().
To put this in a word, system is not using benefits offered by the pcp
lists when there is a single onlineable memory block in a zone. Correct
this by always updating the pcp lists when memory block is onlined.
Fixes:
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Jia He
|
b4223a510e |
mm/memory_hotplug: fix unpaired mem_hotplug_begin/done
When check_memblock_offlined_cb() returns failed rc(e.g. the memblock is
online at that time), mem_hotplug_begin/done is unpaired in such case.
Therefore a warning:
Call Trace:
percpu_up_write+0x33/0x40
try_remove_memory+0x66/0x120
? _cond_resched+0x19/0x30
remove_memory+0x2b/0x40
dev_dax_kmem_remove+0x36/0x72 [kmem]
device_release_driver_internal+0xf0/0x1c0
device_release_driver+0x12/0x20
bus_remove_device+0xe1/0x150
device_del+0x17b/0x3e0
unregister_dev_dax+0x29/0x60
devm_action_release+0x15/0x20
release_nodes+0x19a/0x1e0
devres_release_all+0x3f/0x50
device_release_driver_internal+0x100/0x1c0
driver_detach+0x4c/0x8f
bus_remove_driver+0x5c/0xd0
driver_unregister+0x31/0x50
dax_pmem_exit+0x10/0xfe0 [dax_pmem]
Fixes:
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Jia He
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d622ecec5f |
mm/memory_hotplug: introduce default dummy memory_add_physaddr_to_nid()
This is to introduce a general dummy helper. memory_add_physaddr_to_nid() is a fallback option to get the nid in case NUMA_NO_NID is detected. After this patch, arm64/sh/s390 can simply use the general dummy version. PowerPC/x86/ia64 will still use their specific version. This is the preparation to set a fallback value for dev_dax->target_node. Signed-off-by: Jia He <justin.he@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Baoquan He <bhe@redhat.com> Cc: Chuhong Yuan <hslester96@gmail.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Jonathan Cameron <Jonathan.Cameron@Huawei.com> Cc: Kaly Xin <Kaly.Xin@arm.com> Link: http://lkml.kernel.org/r/20200710031619.18762-2-justin.he@arm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Daniel Jordan
|
fe124c95df |
x86/mm: use max memory block size on bare metal
Some of our servers spend significant time at kernel boot initializing memory block sysfs directories and then creating symlinks between them and the corresponding nodes. The slowness happens because the machines get stuck with the smallest supported memory block size on x86 (128M), which results in 16,288 directories to cover the 2T of installed RAM. The search for each memory block is noticeable even with commit |
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Krzysztof Kozlowski
|
d49653f35a |
mm: mmu_notifier: fix and extend kerneldoc
Fix W=1 compile warnings (invalid kerneldoc):
mm/mmu_notifier.c:187: warning: Function parameter or member 'interval_sub' not described in 'mmu_interval_read_bgin'
mm/mmu_notifier.c:708: warning: Function parameter or member 'subscription' not described in 'mmu_notifier_registr'
mm/mmu_notifier.c:708: warning: Excess function parameter 'mn' description in 'mmu_notifier_register'
mm/mmu_notifier.c:880: warning: Function parameter or member 'subscription' not described in 'mmu_notifier_put'
mm/mmu_notifier.c:880: warning: Excess function parameter 'mn' description in 'mmu_notifier_put'
mm/mmu_notifier.c:982: warning: Function parameter or member 'ops' not described in 'mmu_interval_notifier_insert'
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: http://lkml.kernel.org/r/20200728171109.28687-4-krzk@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Waiman Long
|
af161bee93 |
include/linux/sched/mm.h: optimize current_gfp_context()
The current_gfp_context() converts a number of PF_MEMALLOC_* per-process flags into the corresponding GFP_* flags for memory allocation. In that function, current->flags is accessed 3 times. That may lead to duplicated access of the same memory location. This is not usually a problem with minimal debug config options on as the compiler can optimize away the duplicated memory accesses. With most of the debug config options on, however, that may not be the case. For example, the x86-64 object size of the __need_fs_reclaim() in a debug kernel that calls current_gfp_context() was 309 bytes. With this patch applied, the object size is reduced to 202 bytes. This is a saving of 107 bytes and will probably be slightly faster too. Use READ_ONCE() to access current->flags to prevent the compiler from possibly accessing current->flags multiple times. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Michel Lespinasse <walken@google.com> Link: http://lkml.kernel.org/r/20200618212936.9776-1-longman@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mike Kravetz
|
3a5139f1c5 |
cma: don't quit at first error when activating reserved areas
The routine cma_init_reserved_areas is designed to activate all
reserved cma areas. It quits when it first encounters an error.
This can leave some areas in a state where they are reserved but
not activated. There is no feedback to code which performed the
reservation. Attempting to allocate memory from areas in such a
state will result in a BUG.
Modify cma_init_reserved_areas to always attempt to activate all
areas. The called routine, cma_activate_area is responsible for
leaving the area in a valid state. No one is making active use
of returned error codes, so change the routine to void.
How to reproduce: This example uses kernelcore, hugetlb and cma
as an easy way to reproduce. However, this is a more general cma
issue.
Two node x86 VM 16GB total, 8GB per node
Kernel command line parameters, kernelcore=4G hugetlb_cma=8G
Related boot time messages,
hugetlb_cma: reserve 8192 MiB, up to 4096 MiB per node
cma: Reserved 4096 MiB at 0x0000000100000000
hugetlb_cma: reserved 4096 MiB on node 0
cma: Reserved 4096 MiB at 0x0000000300000000
hugetlb_cma: reserved 4096 MiB on node 1
cma: CMA area hugetlb could not be activated
# echo 8 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
...
Call Trace:
bitmap_find_next_zero_area_off+0x51/0x90
cma_alloc+0x1a5/0x310
alloc_fresh_huge_page+0x78/0x1a0
alloc_pool_huge_page+0x6f/0xf0
set_max_huge_pages+0x10c/0x250
nr_hugepages_store_common+0x92/0x120
? __kmalloc+0x171/0x270
kernfs_fop_write+0xc1/0x1a0
vfs_write+0xc7/0x1f0
ksys_write+0x5f/0xe0
do_syscall_64+0x4d/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes:
|
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Barry Song
|
29d0f41d23 |
mm: hugetlb: fix the name of hugetlb CMA
Once we enable CMA_DEBUGFS, we will get the below errors: directory 'cma-hugetlb' with parent 'cma' already present. We should have different names for different CMA areas. Signed-off-by: Barry Song <song.bao.hua@hisilicon.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: Roman Gushchin <guro@fb.com> Link: http://lkml.kernel.org/r/20200616223131.33828-3-song.bao.hua@hisilicon.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Barry Song
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18e98e56f4 |
mm: cma: fix the name of CMA areas
Patch series "mm: fix the names of general cma and hugetlb cma", v2. The current code of CMA can only work when users pass a const string as name parameter. we need to fix the way to handle names in CMA. On the other hand, to avoid name conflicts after enabling CMA_DEBUGFS, each hugetlb should get a different CMA name. This patch (of 2): If users give a name saved in stack, the current code will generate magic pointer. if users don't give a name(NULL), kasprintf() will always return NULL as we are at the early stage. that means cma_init_reserved_mem() will return -ENOMEM if users set name parameter as NULL. [natechancellor@gmail.com: return cma->name directly in cma_get_name] Link: https://github.com/ClangBuiltLinux/linux/issues/1063 Link: http://lkml.kernel.org/r/20200623015840.621964-1-natechancellor@gmail.com Signed-off-by: Barry Song <song.bao.hua@hisilicon.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: Roman Gushchin <guro@fb.com> Link: http://lkml.kernel.org/r/20200616223131.33828-2-song.bao.hua@hisilicon.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Jianqun Xu
|
835832ba01 |
mm/cma.c: fix NULL pointer dereference when cma could not be activated
In some case the cma area could not be activated, but the cma_alloc be used under this case, then the kernel will crash caused by NULL pointer dereference. Add bitmap valid check in cma_alloc to avoid this issue. Signed-off-by: Jianqun Xu <jay.xu@rock-chips.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Link: http://lkml.kernel.org/r/20200615010123.15596-1-jay.xu@rock-chips.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Anshuman Khandual
|
1a5bae25e3 |
mm/vmstat: add events for THP migration without split
Add following new vmstat events which will help in validating THP migration without split. Statistics reported through these new VM events will help in performance debugging. 1. THP_MIGRATION_SUCCESS 2. THP_MIGRATION_FAILURE 3. THP_MIGRATION_SPLIT In addition, these new events also update normal page migration statistics appropriately via PGMIGRATE_SUCCESS and PGMIGRATE_FAILURE. While here, this updates current trace event 'mm_migrate_pages' to accommodate now available THP statistics. [akpm@linux-foundation.org: s/hpage_nr_pages/thp_nr_pages/] [ziy@nvidia.com: v2] Link: http://lkml.kernel.org/r/C5E3C65C-8253-4638-9D3C-71A61858BB8B@nvidia.com [anshuman.khandual@arm.com: s/thp_nr_pages/hpage_nr_pages/] Link: http://lkml.kernel.org/r/1594287583-16568-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Zi Yan <ziy@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Link: http://lkml.kernel.org/r/1594080415-27924-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Yang Shi
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4958e4d86e |
mm: thp: remove debug_cow switch
Since commit
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Ralph Campbell
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b0fc0f3fca |
mm/migrate: add migrate-shared test for migrate_vma_*()
Add a migrate_vma_*() self test for mmap(MAP_SHARED) to verify that !vma_anonymous() ranges won't be migrated. Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: "Bharata B Rao" <bharata@linux.ibm.com> Cc: Shuah Khan <shuah@kernel.org> Link: http://lkml.kernel.org/r/20200710194840.7602-3-rcampbell@nvidia.com Link: http://lkml.kernel.org/r/20200709165711.26584-3-rcampbell@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Ralph Campbell
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0744f2807a |
mm/migrate: optimize migrate_vma_setup() for holes
Patch series "mm/migrate: optimize migrate_vma_setup() for holes". A simple optimization for migrate_vma_*() when the source vma is not an anonymous vma and a new test case to exercise it. This patch (of 2): When migrating system memory to device private memory, if the source address range is a valid VMA range and there is no memory or a zero page, the source PFN array is marked as valid but with no PFN. This lets the device driver allocate private memory and clear it, then insert the new device private struct page into the CPU's page tables when migrate_vma_pages() is called. migrate_vma_pages() only inserts the new page if the VMA is an anonymous range. There is no point in telling the device driver to allocate device private memory and then not migrate the page. Instead, mark the source PFN array entries as not migrating to avoid this overhead. [rcampbell@nvidia.com: v2] Link: http://lkml.kernel.org/r/20200710194840.7602-2-rcampbell@nvidia.com Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: "Bharata B Rao" <bharata@linux.ibm.com> Cc: Shuah Khan <shuah@kernel.org> Link: http://lkml.kernel.org/r/20200710194840.7602-1-rcampbell@nvidia.com Link: http://lkml.kernel.org/r/20200709165711.26584-1-rcampbell@nvidia.com Link: http://lkml.kernel.org/r/20200709165711.26584-2-rcampbell@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mike Kravetz
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34ae204f18 |
hugetlbfs: remove call to huge_pte_alloc without i_mmap_rwsem
Commit |
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Mike Kravetz
|
15568299b7 |
hugetlbfs: prevent filesystem stacking of hugetlbfs
syzbot found issues with having hugetlbfs on a union/overlay as reported in [1]. Due to the limitations (no write) and special functionality of hugetlbfs, it does not work well in filesystem stacking. There are no know use cases for hugetlbfs stacking. Rather than making modifications to get hugetlbfs working in such environments, simply prevent stacking. [1] https://lore.kernel.org/linux-mm/000000000000b4684e05a2968ca6@google.com/ Reported-by: syzbot+d6ec23007e951dadf3de@syzkaller.appspotmail.com Suggested-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Miklos Szeredi <mszeredi@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Matthew Wilcox <willy@infradead.org> Cc: Colin Walters <walters@verbum.org> Link: http://lkml.kernel.org/r/80f869aa-810d-ef6c-8888-b46cee135907@oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Yafang Shao
|
619b5b469b |
mm, oom: show process exiting information in __oom_kill_process()
When the OOM killer finds a victim and tryies to kill it, if the victim is already exiting, the task mm will be NULL and no process will be killed. But the dump_header() has been already executed, so it will be strange to dump so much information without killing a process. We'd better show some helpful information to indicate why this happens. Suggested-by: David Rientjes <rientjes@google.com> Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: Qian Cai <cai@lca.pw> Link: http://lkml.kernel.org/r/20200721010127.17238-1-laoar.shao@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
|
b1aa7c9377 |
doc, mm: clarify /proc/<pid>/oom_score value range
The exported value includes oom_score_adj so the range is no [0, 1000] as described in the previous section but rather [0, 2000]. Mention that fact explicitly. Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: David Rientjes <rientjes@google.com> Cc: Yafang Shao <laoar.shao@gmail.com> Link: http://lkml.kernel.org/r/20200709062603.18480-2-mhocko@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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de3f32e142 |
doc, mm: sync up oom_score_adj documentation
There are at least two notes in the oom section. The 3% discount for root processes is gone since |
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Yafang Shao
|
9066e5cfb7 |
mm, oom: make the calculation of oom badness more accurate
Recently we found an issue on our production environment that when memcg oom is triggered the oom killer doesn't chose the process with largest resident memory but chose the first scanned process. Note that all processes in this memcg have the same oom_score_adj, so the oom killer should chose the process with largest resident memory. Bellow is part of the oom info, which is enough to analyze this issue. [7516987.983223] memory: usage 16777216kB, limit 16777216kB, failcnt 52843037 [7516987.983224] memory+swap: usage 16777216kB, limit 9007199254740988kB, failcnt 0 [7516987.983225] kmem: usage 301464kB, limit 9007199254740988kB, failcnt 0 [...] [7516987.983293] [ pid ] uid tgid total_vm rss pgtables_bytes swapents oom_score_adj name [7516987.983510] [ 5740] 0 5740 257 1 32768 0 -998 pause [7516987.983574] [58804] 0 58804 4594 771 81920 0 -998 entry_point.bas [7516987.983577] [58908] 0 58908 7089 689 98304 0 -998 cron [7516987.983580] [58910] 0 58910 16235 5576 163840 0 -998 supervisord [7516987.983590] [59620] 0 59620 18074 1395 188416 0 -998 sshd [7516987.983594] [59622] 0 59622 18680 6679 188416 0 -998 python [7516987.983598] [59624] 0 59624 1859266 5161 548864 0 -998 odin-agent [7516987.983600] [59625] 0 59625 707223 9248 983040 0 -998 filebeat [7516987.983604] [59627] 0 59627 416433 64239 774144 0 -998 odin-log-agent [7516987.983607] [59631] 0 59631 180671 15012 385024 0 -998 python3 [7516987.983612] [61396] 0 61396 791287 3189 352256 0 -998 client [7516987.983615] [61641] 0 61641 1844642 29089 946176 0 -998 client [7516987.983765] [ 9236] 0 9236 2642 467 53248 0 -998 php_scanner [7516987.983911] [42898] 0 42898 15543 838 167936 0 -998 su [7516987.983915] [42900] 1000 42900 3673 867 77824 0 -998 exec_script_vr2 [7516987.983918] [42925] 1000 42925 36475 19033 335872 0 -998 python [7516987.983921] [57146] 1000 57146 3673 848 73728 0 -998 exec_script_J2p [7516987.983925] [57195] 1000 57195 186359 22958 491520 0 -998 python2 [7516987.983928] [58376] 1000 58376 275764 14402 290816 0 -998 rosmaster [7516987.983931] [58395] 1000 58395 155166 4449 245760 0 -998 rosout [7516987.983935] [58406] 1000 58406 18285584 3967322 37101568 0 -998 data_sim [7516987.984221] oom-kill:constraint=CONSTRAINT_MEMCG,nodemask=(null),cpuset=3aa16c9482ae3a6f6b78bda68a55d32c87c99b985e0f11331cddf05af6c4d753,mems_allowed=0-1,oom_memcg=/kubepods/podf1c273d3-9b36-11ea-b3df-246e9693c184,task_memcg=/kubepods/podf1c273d3-9b36-11ea-b3df-246e9693c184/1f246a3eeea8f70bf91141eeaf1805346a666e225f823906485ea0b6c37dfc3d,task=pause,pid=5740,uid=0 [7516987.984254] Memory cgroup out of memory: Killed process 5740 (pause) total-vm:1028kB, anon-rss:4kB, file-rss:0kB, shmem-rss:0kB [7516988.092344] oom_reaper: reaped process 5740 (pause), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB We can find that the first scanned process 5740 (pause) was killed, but its rss is only one page. That is because, when we calculate the oom badness in oom_badness(), we always ignore the negtive point and convert all of these negtive points to 1. Now as oom_score_adj of all the processes in this targeted memcg have the same value -998, the points of these processes are all negtive value. As a result, the first scanned process will be killed. The oom_socre_adj (-998) in this memcg is set by kubelet, because it is a a Guaranteed pod, which has higher priority to prevent from being killed by system oom. To fix this issue, we should make the calculation of oom point more accurate. We can achieve it by convert the chosen_point from 'unsigned long' to 'long'. [cai@lca.pw: reported a issue in the previous version] [mhocko@suse.com: fixed the issue reported by Cai] [mhocko@suse.com: add the comment in proc_oom_score()] [laoar.shao@gmail.com: v3] Link: http://lkml.kernel.org/r/1594396651-9931-1-git-send-email-laoar.shao@gmail.com Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: Qian Cai <cai@lca.pw> Link: http://lkml.kernel.org/r/1594309987-9919-1-git-send-email-laoar.shao@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
Yanfei Xu
|
f3f3416c22 |
include/linux/mempolicy.h: fix typo
Change "interlave" to "interleave". Signed-off-by: Yanfei Xu <yanfei.xu@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200810063454.9357-1-yanfei.xu@windriver.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
Wenchao Hao
|
4605f057aa |
mm/mempolicy.c: check parameters first in kernel_get_mempolicy
Previous implementatoin calls untagged_addr() before error check, while if the error check failed and return EINVAL, the untagged_addr() call is just useless work. Signed-off-by: Wenchao Hao <haowenchao22@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200801090825.5597-1-haowenchao22@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Krzysztof Kozlowski
|
f6e92f4048 |
mm: mempolicy: fix kerneldoc of numa_map_to_online_node()
Fix W=1 compile warnings (invalid kerneldoc):
mm/mempolicy.c:137: warning: Function parameter or member 'node' not described in 'numa_map_to_online_node'
mm/mempolicy.c:137: warning: Excess function parameter 'nid' description in 'numa_map_to_online_node'
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200728171109.28687-3-krzk@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
||
Alex Shi
|
860b32729a |
mm/compaction: correct the comments of compact_defer_shift
There is no compact_defer_limit. It should be compact_defer_shift in use. and add compact_order_failed explanation. Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Link: http://lkml.kernel.org/r/3bd60e1b-a74e-050d-ade4-6e8f54e00b92@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
Nitin Gupta
|
d34c0a7599 |
mm: use unsigned types for fragmentation score
Proactive compaction uses per-node/zone "fragmentation score" which is always in range [0, 100], so use unsigned type of these scores as well as for related constants. Signed-off-by: Nitin Gupta <nigupta@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Baoquan He <bhe@redhat.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Iurii Zaikin <yzaikin@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Link: http://lkml.kernel.org/r/20200618010319.13159-1-nigupta@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Nitin Gupta
|
25788738eb |
mm: fix compile error due to COMPACTION_HPAGE_ORDER
Fix compile error when COMPACTION_HPAGE_ORDER is assigned to HUGETLB_PAGE_ORDER. The correct way to check if this constant is defined is to check for CONFIG_HUGETLBFS. Reported-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Nitin Gupta <nigupta@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Link: http://lkml.kernel.org/r/20200623064544.25766-1-nigupta@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Nitin Gupta
|
facdaa917c |
mm: proactive compaction
For some applications, we need to allocate almost all memory as hugepages.
However, on a running system, higher-order allocations can fail if the
memory is fragmented. Linux kernel currently does on-demand compaction as
we request more hugepages, but this style of compaction incurs very high
latency. Experiments with one-time full memory compaction (followed by
hugepage allocations) show that kernel is able to restore a highly
fragmented memory state to a fairly compacted memory state within <1 sec
for a 32G system. Such data suggests that a more proactive compaction can
help us allocate a large fraction of memory as hugepages keeping
allocation latencies low.
For a more proactive compaction, the approach taken here is to define a
new sysctl called 'vm.compaction_proactiveness' which dictates bounds for
external fragmentation which kcompactd tries to maintain.
The tunable takes a value in range [0, 100], with a default of 20.
Note that a previous version of this patch [1] was found to introduce too
many tunables (per-order extfrag{low, high}), but this one reduces them to
just one sysctl. Also, the new tunable is an opaque value instead of
asking for specific bounds of "external fragmentation", which would have
been difficult to estimate. The internal interpretation of this opaque
value allows for future fine-tuning.
Currently, we use a simple translation from this tunable to [low, high]
"fragmentation score" thresholds (low=100-proactiveness, high=low+10%).
The score for a node is defined as weighted mean of per-zone external
fragmentation. A zone's present_pages determines its weight.
To periodically check per-node score, we reuse per-node kcompactd threads,
which are woken up every 500 milliseconds to check the same. If a node's
score exceeds its high threshold (as derived from user-provided
proactiveness value), proactive compaction is started until its score
reaches its low threshold value. By default, proactiveness is set to 20,
which implies threshold values of low=80 and high=90.
This patch is largely based on ideas from Michal Hocko [2]. See also the
LWN article [3].
Performance data
================
System: x64_64, 1T RAM, 80 CPU threads.
Kernel: 5.6.0-rc3 + this patch
echo madvise | sudo tee /sys/kernel/mm/transparent_hugepage/enabled
echo madvise | sudo tee /sys/kernel/mm/transparent_hugepage/defrag
Before starting the driver, the system was fragmented from a userspace
program that allocates all memory and then for each 2M aligned section,
frees 3/4 of base pages using munmap. The workload is mainly anonymous
userspace pages, which are easy to move around. I intentionally avoided
unmovable pages in this test to see how much latency we incur when
hugepage allocations hit direct compaction.
1. Kernel hugepage allocation latencies
With the system in such a fragmented state, a kernel driver then allocates
as many hugepages as possible and measures allocation latency:
(all latency values are in microseconds)
- With vanilla 5.6.0-rc3
percentile latency
–––––––––– –––––––
5 7894
10 9496
25 12561
30 15295
40 18244
50 21229
60 27556
75 30147
80 31047
90 32859
95 33799
Total 2M hugepages allocated = 383859 (749G worth of hugepages out of 762G
total free => 98% of free memory could be allocated as hugepages)
- With 5.6.0-rc3 + this patch, with proactiveness=20
sysctl -w vm.compaction_proactiveness=20
percentile latency
–––––––––– –––––––
5 2
10 2
25 3
30 3
40 3
50 4
60 4
75 4
80 4
90 5
95 429
Total 2M hugepages allocated = 384105 (750G worth of hugepages out of 762G
total free => 98% of free memory could be allocated as hugepages)
2. JAVA heap allocation
In this test, we first fragment memory using the same method as for (1).
Then, we start a Java process with a heap size set to 700G and request the
heap to be allocated with THP hugepages. We also set THP to madvise to
allow hugepage backing of this heap.
/usr/bin/time
java -Xms700G -Xmx700G -XX:+UseTransparentHugePages -XX:+AlwaysPreTouch
The above command allocates 700G of Java heap using hugepages.
- With vanilla 5.6.0-rc3
17.39user 1666.48system 27:37.89elapsed
- With 5.6.0-rc3 + this patch, with proactiveness=20
8.35user 194.58system 3:19.62elapsed
Elapsed time remains around 3:15, as proactiveness is further increased.
Note that proactive compaction happens throughout the runtime of these
workloads. The situation of one-time compaction, sufficient to supply
hugepages for following allocation stream, can probably happen for more
extreme proactiveness values, like 80 or 90.
In the above Java workload, proactiveness is set to 20. The test starts
with a node's score of 80 or higher, depending on the delay between the
fragmentation step and starting the benchmark, which gives more-or-less
time for the initial round of compaction. As t he benchmark consumes
hugepages, node's score quickly rises above the high threshold (90) and
proactive compaction starts again, which brings down the score to the low
threshold level (80). Repeat.
bpftrace also confirms proactive compaction running 20+ times during the
runtime of this Java benchmark. kcompactd threads consume 100% of one of
the CPUs while it tries to bring a node's score within thresholds.
Backoff behavior
================
Above workloads produce a memory state which is easy to compact. However,
if memory is filled with unmovable pages, proactive compaction should
essentially back off. To test this aspect:
- Created a kernel driver that allocates almost all memory as hugepages
followed by freeing first 3/4 of each hugepage.
- Set proactiveness=40
- Note that proactive_compact_node() is deferred maximum number of times
with HPAGE_FRAG_CHECK_INTERVAL_MSEC of wait between each check
(=> ~30 seconds between retries).
[1] https://patchwork.kernel.org/patch/11098289/
[2] https://lore.kernel.org/linux-mm/20161230131412.GI13301@dhcp22.suse.cz/
[3] https://lwn.net/Articles/817905/
Signed-off-by: Nitin Gupta <nigupta@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Oleksandr Natalenko <oleksandr@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Reviewed-by: Oleksandr Natalenko <oleksandr@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Nitin Gupta <ngupta@nitingupta.dev>
Cc: Oleksandr Natalenko <oleksandr@redhat.com>
Link: http://lkml.kernel.org/r/20200616204527.19185-1-nigupta@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
||
Michal Koutný
|
471e78cc76 |
/proc/PID/smaps: consistent whitespace output format
The keys in smaps output are padded to fixed width with spaces. All
except for THPeligible that uses tabs (only since commit
|
||
Joonsoo Kim
|
4002570c5c |
mm/vmscan: restore active/inactive ratio for anonymous LRU
Now that workingset detection is implemented for anonymous LRU, we don't need large inactive list to allow detecting frequently accessed pages before they are reclaimed, anymore. This effectively reverts the temporary measure put in by commit "mm/vmscan: make active/inactive ratio as 1:1 for anon lru". Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Link: http://lkml.kernel.org/r/1595490560-15117-7-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Joonsoo Kim
|
aae466b005 |
mm/swap: implement workingset detection for anonymous LRU
This patch implements workingset detection for anonymous LRU. All the infrastructure is implemented by the previous patches so this patch just activates the workingset detection by installing/retrieving the shadow entry and adding refault calculation. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Link: http://lkml.kernel.org/r/1595490560-15117-6-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Joonsoo Kim
|
3852f6768e |
mm/swapcache: support to handle the shadow entries
Workingset detection for anonymous page will be implemented in the following patch and it requires to store the shadow entries into the swapcache. This patch implements an infrastructure to store the shadow entry in the swapcache. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/1595490560-15117-5-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Joonsoo Kim
|
170b04b7ae |
mm/workingset: prepare the workingset detection infrastructure for anon LRU
To prepare the workingset detection for anon LRU, this patch splits workingset event counters for refault, activate and restore into anon and file variants, as well as the refaults counter in struct lruvec. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Link: http://lkml.kernel.org/r/1595490560-15117-4-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Joonsoo Kim
|
b518154e59 |
mm/vmscan: protect the workingset on anonymous LRU
In current implementation, newly created or swap-in anonymous page is started on active list. Growing active list results in rebalancing active/inactive list so old pages on active list are demoted to inactive list. Hence, the page on active list isn't protected at all. Following is an example of this situation. Assume that 50 hot pages on active list. Numbers denote the number of pages on active/inactive list (active | inactive). 1. 50 hot pages on active list 50(h) | 0 2. workload: 50 newly created (used-once) pages 50(uo) | 50(h) 3. workload: another 50 newly created (used-once) pages 50(uo) | 50(uo), swap-out 50(h) This patch tries to fix this issue. Like as file LRU, newly created or swap-in anonymous pages will be inserted to the inactive list. They are promoted to active list if enough reference happens. This simple modification changes the above example as following. 1. 50 hot pages on active list 50(h) | 0 2. workload: 50 newly created (used-once) pages 50(h) | 50(uo) 3. workload: another 50 newly created (used-once) pages 50(h) | 50(uo), swap-out 50(uo) As you can see, hot pages on active list would be protected. Note that, this implementation has a drawback that the page cannot be promoted and will be swapped-out if re-access interval is greater than the size of inactive list but less than the size of total(active+inactive). To solve this potential issue, following patch will apply workingset detection similar to the one that's already applied to file LRU. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Link: http://lkml.kernel.org/r/1595490560-15117-3-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Joonsoo Kim
|
ccc5dc6734 |
mm/vmscan: make active/inactive ratio as 1:1 for anon lru
Patch series "workingset protection/detection on the anonymous LRU list", v7.
* PROBLEM
In current implementation, newly created or swap-in anonymous page is
started on the active list. Growing the active list results in
rebalancing active/inactive list so old pages on the active list are
demoted to the inactive list. Hence, hot page on the active list isn't
protected at all.
Following is an example of this situation.
Assume that 50 hot pages on active list and system can contain total 100
pages. Numbers denote the number of pages on active/inactive list (active
| inactive). (h) stands for hot pages and (uo) stands for used-once
pages.
1. 50 hot pages on active list
50(h) | 0
2. workload: 50 newly created (used-once) pages
50(uo) | 50(h)
3. workload: another 50 newly created (used-once) pages
50(uo) | 50(uo), swap-out 50(h)
As we can see, hot pages are swapped-out and it would cause swap-in later.
* SOLUTION
Since this is what we want to avoid, this patchset implements workingset
protection. Like as the file LRU list, newly created or swap-in anonymous
page is started on the inactive list. Also, like as the file LRU list, if
enough reference happens, the page will be promoted. This simple
modification changes the above example as following.
1. 50 hot pages on active list
50(h) | 0
2. workload: 50 newly created (used-once) pages
50(h) | 50(uo)
3. workload: another 50 newly created (used-once) pages
50(h) | 50(uo), swap-out 50(uo)
hot pages remains in the active list. :)
* EXPERIMENT
I tested this scenario on my test bed and confirmed that this problem
happens on current implementation. I also checked that it is fixed by
this patchset.
* SUBJECT
workingset detection
* PROBLEM
Later part of the patchset implements the workingset detection for the
anonymous LRU list. There is a corner case that workingset protection
could cause thrashing. If we can avoid thrashing by workingset detection,
we can get the better performance.
Following is an example of thrashing due to the workingset protection.
1. 50 hot pages on active list
50(h) | 0
2. workload: 50 newly created (will be hot) pages
50(h) | 50(wh)
3. workload: another 50 newly created (used-once) pages
50(h) | 50(uo), swap-out 50(wh)
4. workload: 50 (will be hot) pages
50(h) | 50(wh), swap-in 50(wh)
5. workload: another 50 newly created (used-once) pages
50(h) | 50(uo), swap-out 50(wh)
6. repeat 4, 5
Without workingset detection, this kind of workload cannot be promoted and
thrashing happens forever.
* SOLUTION
Therefore, this patchset implements workingset detection. All the
infrastructure for workingset detecion is already implemented, so there is
not much work to do. First, extend workingset detection code to deal with
the anonymous LRU list. Then, make swap cache handles the exceptional
value for the shadow entry. Lastly, install/retrieve the shadow value
into/from the swap cache and check the refault distance.
* EXPERIMENT
I made a test program to imitates above scenario and confirmed that
problem exists. Then, I checked that this patchset fixes it.
My test setup is a virtual machine with 8 cpus and 6100MB memory. But,
the amount of the memory that the test program can use is about 280 MB.
This is because the system uses large ram-backed swap and large ramdisk to
capture the trace.
Test scenario is like as below.
1. allocate cold memory (512MB)
2. allocate hot-1 memory (96MB)
3. activate hot-1 memory (96MB)
4. allocate another hot-2 memory (96MB)
5. access cold memory (128MB)
6. access hot-2 memory (96MB)
7. repeat 5, 6
Since hot-1 memory (96MB) is on the active list, the inactive list can
contains roughly 190MB pages. hot-2 memory's re-access interval (96+128
MB) is more 190MB, so it cannot be promoted without workingset detection
and swap-in/out happens repeatedly. With this patchset, workingset
detection works and promotion happens. Therefore, swap-in/out occurs
less.
Here is the result. (average of 5 runs)
type swap-in swap-out
base 863240 989945
patch 681565 809273
As we can see, patched kernel do less swap-in/out.
* OVERALL TEST (ebizzy using modified random function)
ebizzy is the test program that main thread allocates lots of memory and
child threads access them randomly during the given times. Swap-in will
happen if allocated memory is larger than the system memory.
The random function that represents the zipf distribution is used to make
hot/cold memory. Hot/cold ratio is controlled by the parameter. If the
parameter is high, hot memory is accessed much larger than cold one. If
the parameter is low, the number of access on each memory would be
similar. I uses various parameters in order to show the effect of
patchset on various hot/cold ratio workload.
My test setup is a virtual machine with 8 cpus, 1024 MB memory and 5120 MB
ram swap.
Result format is as following.
param: 1-1024-0.1
- 1 (number of thread)
- 1024 (allocated memory size, MB)
- 0.1 (zipf distribution alpha,
0.1 works like as roughly uniform random,
1.3 works like as small portion of memory is hot and the others are cold)
pswpin: smaller is better
std: standard deviation
improvement: negative is better
* single thread
param pswpin std improvement
base 1-1024.0-0.1 14101983.40 79441.19
prot 1-1024.0-0.1 14065875.80 136413.01 ( -0.26 )
detect 1-1024.0-0.1 13910435.60 100804.82 ( -1.36 )
base 1-1024.0-0.7 7998368.80 43469.32
prot 1-1024.0-0.7 7622245.80 88318.74 ( -4.70 )
detect 1-1024.0-0.7 7618515.20 59742.07 ( -4.75 )
base 1-1024.0-1.3 1017400.80 38756.30
prot 1-1024.0-1.3 940464.60 29310.69 ( -7.56 )
detect 1-1024.0-1.3 945511.40 24579.52 ( -7.07 )
base 1-1280.0-0.1 22895541.40 50016.08
prot 1-1280.0-0.1 22860305.40 51952.37 ( -0.15 )
detect 1-1280.0-0.1 22705565.20 93380.35 ( -0.83 )
base 1-1280.0-0.7 13717645.60 46250.65
prot 1-1280.0-0.7 12935355.80 64754.43 ( -5.70 )
detect 1-1280.0-0.7 13040232.00 63304.00 ( -4.94 )
base 1-1280.0-1.3 1654251.40 4159.68
prot 1-1280.0-1.3 1522680.60 33673.50 ( -7.95 )
detect 1-1280.0-1.3 1599207.00 70327.89 ( -3.33 )
base 1-1536.0-0.1 31621775.40 31156.28
prot 1-1536.0-0.1 31540355.20 62241.36 ( -0.26 )
detect 1-1536.0-0.1 31420056.00 123831.27 ( -0.64 )
base 1-1536.0-0.7 19620760.60 60937.60
prot 1-1536.0-0.7 18337839.60 56102.58 ( -6.54 )
detect 1-1536.0-0.7 18599128.00 75289.48 ( -5.21 )
base 1-1536.0-1.3 2378142.40 20994.43
prot 1-1536.0-1.3 2166260.60 48455.46 ( -8.91 )
detect 1-1536.0-1.3 2183762.20 16883.24 ( -8.17 )
base 1-1792.0-0.1 40259714.80 90750.70
prot 1-1792.0-0.1 40053917.20 64509.47 ( -0.51 )
detect 1-1792.0-0.1 39949736.40 104989.64 ( -0.77 )
base 1-1792.0-0.7 25704884.40 69429.68
prot 1-1792.0-0.7 23937389.00 79945.60 ( -6.88 )
detect 1-1792.0-0.7 24271902.00 35044.30 ( -5.57 )
base 1-1792.0-1.3 3129497.00 32731.86
prot 1-1792.0-1.3 2796994.40 19017.26 ( -10.62 )
detect 1-1792.0-1.3 2886840.40 33938.82 ( -7.75 )
base 1-2048.0-0.1 48746924.40 50863.88
prot 1-2048.0-0.1 48631954.40 24537.30 ( -0.24 )
detect 1-2048.0-0.1 48509419.80 27085.34 ( -0.49 )
base 1-2048.0-0.7 32046424.40 78624.22
prot 1-2048.0-0.7 29764182.20 86002.26 ( -7.12 )
detect 1-2048.0-0.7 30250315.80 101282.14 ( -5.60 )
base 1-2048.0-1.3 3916723.60 24048.55
prot 1-2048.0-1.3 3490781.60 33292.61 ( -10.87 )
detect 1-2048.0-1.3 3585002.20 44942.04 ( -8.47 )
* multi thread
param pswpin std improvement
base 8-1024.0-0.1 16219822.60 329474.01
prot 8-1024.0-0.1 15959494.00 654597.45 ( -1.61 )
detect 8-1024.0-0.1 15773790.80 502275.25 ( -2.75 )
base 8-1024.0-0.7 9174107.80 537619.33
prot 8-1024.0-0.7 8571915.00 385230.08 ( -6.56 )
detect 8-1024.0-0.7 8489484.20 364683.00 ( -7.46 )
base 8-1024.0-1.3 1108495.60 83555.98
prot 8-1024.0-1.3 1038906.20 63465.20 ( -6.28 )
detect 8-1024.0-1.3 941817.80 32648.80 ( -15.04 )
base 8-1280.0-0.1 25776114.20 450480.45
prot 8-1280.0-0.1 25430847.00 465627.07 ( -1.34 )
detect 8-1280.0-0.1 25282555.00 465666.55 ( -1.91 )
base 8-1280.0-0.7 15218968.00 702007.69
prot 8-1280.0-0.7 13957947.80 492643.86 ( -8.29 )
detect 8-1280.0-0.7 14158331.20 238656.02 ( -6.97 )
base 8-1280.0-1.3 1792482.80 30512.90
prot 8-1280.0-1.3 1577686.40 34002.62 ( -11.98 )
detect 8-1280.0-1.3 1556133.00 22944.79 ( -13.19 )
base 8-1536.0-0.1 33923761.40 575455.85
prot 8-1536.0-0.1 32715766.20 300633.51 ( -3.56 )
detect 8-1536.0-0.1 33158477.40 117764.51 ( -2.26 )
base 8-1536.0-0.7 20628907.80 303851.34
prot 8-1536.0-0.7 19329511.20 341719.31 ( -6.30 )
detect 8-1536.0-0.7 20013934.00 385358.66 ( -2.98 )
base 8-1536.0-1.3 2588106.40 130769.20
prot 8-1536.0-1.3 2275222.40 89637.06 ( -12.09 )
detect 8-1536.0-1.3 2365008.40 124412.55 ( -8.62 )
base 8-1792.0-0.1 43328279.20 946469.12
prot 8-1792.0-0.1 41481980.80 525690.89 ( -4.26 )
detect 8-1792.0-0.1 41713944.60 406798.93 ( -3.73 )
base 8-1792.0-0.7 27155647.40 536253.57
prot 8-1792.0-0.7 24989406.80 502734.52 ( -7.98 )
detect 8-1792.0-0.7 25524806.40 263237.87 ( -6.01 )
base 8-1792.0-1.3 3260372.80 137907.92
prot 8-1792.0-1.3 2879187.80 63597.26 ( -11.69 )
detect 8-1792.0-1.3 2892962.20 33229.13 ( -11.27 )
base 8-2048.0-0.1 50583989.80 710121.48
prot 8-2048.0-0.1 49599984.40 228782.42 ( -1.95 )
detect 8-2048.0-0.1 50578596.00 660971.66 ( -0.01 )
base 8-2048.0-0.7 33765479.60 812659.55
prot 8-2048.0-0.7 30767021.20 462907.24 ( -8.88 )
detect 8-2048.0-0.7 32213068.80 211884.24 ( -4.60 )
base 8-2048.0-1.3 3941675.80 28436.45
prot 8-2048.0-1.3 3538742.40 76856.08 ( -10.22 )
detect 8-2048.0-1.3 3579397.80 58630.95 ( -9.19 )
As we can see, all the cases show improvement. Especially, test case with
zipf distribution 1.3 show more improvements. It means that if there is a
hot/cold tendency in anon pages, this patchset works better.
This patch (of 6):
Current implementation of LRU management for anonymous page has some
problems. Most important one is that it doesn't protect the workingset,
that is, pages on the active LRU list. Although, this problem will be
fixed in the following patchset, the preparation is required and this
patch does it.
What following patch does is to implement workingset protection. After
the following patchset, newly created or swap-in pages will start their
lifetime on the inactive list. If inactive list is too small, there is
not enough chance to be referenced and the page cannot become the
workingset.
In order to provide the newly anonymous or swap-in pages enough chance to
be referenced again, this patch makes active/inactive LRU ratio as 1:1.
This is just a temporary measure. Later patch in the series introduces
workingset detection for anonymous LRU that will be used to better decide
if pages should start on the active and inactive list. Afterwards this
patch is effectively reverted.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Matthew Wilcox <willy@infradead.org>
Link: http://lkml.kernel.org/r/1595490560-15117-1-git-send-email-iamjoonsoo.kim@lge.com
Link: http://lkml.kernel.org/r/1595490560-15117-2-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
||
Muchun Song
|
8ca39e6874 |
mm/hugetlb: add mempolicy check in the reservation routine
In the reservation routine, we only check whether the cpuset meets the
memory allocation requirements. But we ignore the mempolicy of MPOL_BIND
case. If someone mmap hugetlb succeeds, but the subsequent memory
allocation may fail due to mempolicy restrictions and receives the SIGBUS
signal. This can be reproduced by the follow steps.
1) Compile the test case.
cd tools/testing/selftests/vm/
gcc map_hugetlb.c -o map_hugetlb
2) Pre-allocate huge pages. Suppose there are 2 numa nodes in the
system. Each node will pre-allocate one huge page.
echo 2 > /proc/sys/vm/nr_hugepages
3) Run test case(mmap 4MB). We receive the SIGBUS signal.
numactl --membind=3D0 ./map_hugetlb 4
With this patch applied, the mmap will fail in the step 3) and throw
"mmap: Cannot allocate memory".
[akpm@linux-foundation.org: include sched.h for `current']
Reported-by: Jianchao Guo <guojianchao@bytedance.com>
Suggested-by: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michel Lespinasse <walken@google.com>
Cc: Baoquan He <bhe@redhat.com>
Link: http://lkml.kernel.org/r/20200728034938.14993-1-songmuchun@bytedance.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
||
Roman Gushchin
|
90631e1dea |
kselftests: cgroup: add perpcu memory accounting test
Add a simple test to check the percpu memory accounting. The test creates a cgroup tree with 1000 child cgroups and checks values of memory.current and memory.stat::percpu. Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Tobin C. Harding <tobin@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Waiman Long <longman@redhat.com> Cc: Michal Koutný <mkoutny@suse.com> Cc: Bixuan Cui <cuibixuan@huawei.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Link: http://lkml.kernel.org/r/20200608230819.832349-6-guro@fb.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Roman Gushchin
|
3e38e0aaca |
mm: memcg: charge memcg percpu memory to the parent cgroup
Memory cgroups are using large chunks of percpu memory to store vmstat data. Yet this memory is not accounted at all, so in the case when there are many (dying) cgroups, it's not exactly clear where all the memory is. Because the size of memory cgroup internal structures can dramatically exceed the size of object or page which is pinning it in the memory, it's not a good idea to simply ignore it. It actually breaks the isolation between cgroups. Let's account the consumed percpu memory to the parent cgroup. [guro@fb.com: add WARN_ON_ONCE()s, per Johannes] Link: http://lkml.kernel.org/r/20200811170611.GB1507044@carbon.DHCP.thefacebook.com Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Dennis Zhou <dennis@kernel.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Tobin C. Harding <tobin@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Waiman Long <longman@redhat.com> Cc: Bixuan Cui <cuibixuan@huawei.com> Cc: Michal Koutný <mkoutny@suse.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Link: http://lkml.kernel.org/r/20200623184515.4132564-5-guro@fb.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Roman Gushchin
|
772616b031 |
mm: memcg/percpu: per-memcg percpu memory statistics
Percpu memory can represent a noticeable chunk of the total memory consumption, especially on big machines with many CPUs. Let's track percpu memory usage for each memcg and display it in memory.stat. A percpu allocation is usually scattered over multiple pages (and nodes), and can be significantly smaller than a page. So let's add a byte-sized counter on the memcg level: MEMCG_PERCPU_B. Byte-sized vmstat infra created for slabs can be perfectly reused for percpu case. [guro@fb.com: v3] Link: http://lkml.kernel.org/r/20200623184515.4132564-4-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Dennis Zhou <dennis@kernel.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Tobin C. Harding <tobin@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Waiman Long <longman@redhat.com> Cc: Bixuan Cui <cuibixuan@huawei.com> Cc: Michal Koutný <mkoutny@suse.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Link: http://lkml.kernel.org/r/20200608230819.832349-4-guro@fb.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Roman Gushchin
|
3c7be18ac9 |
mm: memcg/percpu: account percpu memory to memory cgroups
Percpu memory is becoming more and more widely used by various subsystems, and the total amount of memory controlled by the percpu allocator can make a good part of the total memory. As an example, bpf maps can consume a lot of percpu memory, and they are created by a user. Also, some cgroup internals (e.g. memory controller statistics) can be quite large. On a machine with many CPUs and big number of cgroups they can consume hundreds of megabytes. So the lack of memcg accounting is creating a breach in the memory isolation. Similar to the slab memory, percpu memory should be accounted by default. To implement the perpcu accounting it's possible to take the slab memory accounting as a model to follow. Let's introduce two types of percpu chunks: root and memcg. What makes memcg chunks different is an additional space allocated to store memcg membership information. If __GFP_ACCOUNT is passed on allocation, a memcg chunk should be be used. If it's possible to charge the corresponding size to the target memory cgroup, allocation is performed, and the memcg ownership data is recorded. System-wide allocations are performed using root chunks, so there is no additional memory overhead. To implement a fast reparenting of percpu memory on memcg removal, we don't store mem_cgroup pointers directly: instead we use obj_cgroup API, introduced for slab accounting. [akpm@linux-foundation.org: fix CONFIG_MEMCG_KMEM=n build errors and warning] [akpm@linux-foundation.org: move unreachable code, per Roman] [cuibixuan@huawei.com: mm/percpu: fix 'defined but not used' warning] Link: http://lkml.kernel.org/r/6d41b939-a741-b521-a7a2-e7296ec16219@huawei.com Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Bixuan Cui <cuibixuan@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Dennis Zhou <dennis@kernel.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Tobin C. Harding <tobin@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Waiman Long <longman@redhat.com> Cc: Bixuan Cui <cuibixuan@huawei.com> Cc: Michal Koutný <mkoutny@suse.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Link: http://lkml.kernel.org/r/20200623184515.4132564-3-guro@fb.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Roman Gushchin
|
5b32af91b5 |
percpu: return number of released bytes from pcpu_free_area()
Patch series "mm: memcg accounting of percpu memory", v3. This patchset adds percpu memory accounting to memory cgroups. It's based on the rework of the slab controller and reuses concepts and features introduced for the per-object slab accounting. Percpu memory is becoming more and more widely used by various subsystems, and the total amount of memory controlled by the percpu allocator can make a good part of the total memory. As an example, bpf maps can consume a lot of percpu memory, and they are created by a user. Also, some cgroup internals (e.g. memory controller statistics) can be quite large. On a machine with many CPUs and big number of cgroups they can consume hundreds of megabytes. So the lack of memcg accounting is creating a breach in the memory isolation. Similar to the slab memory, percpu memory should be accounted by default. Percpu allocations by their nature are scattered over multiple pages, so they can't be tracked on the per-page basis. So the per-object tracking introduced by the new slab controller is reused. The patchset implements charging of percpu allocations, adds memcg-level statistics, enables accounting for percpu allocations made by memory cgroup internals and provides some basic tests. To implement the accounting of percpu memory without a significant memory and performance overhead the following approach is used: all accounted allocations are placed into a separate percpu chunk (or chunks). These chunks are similar to default chunks, except that they do have an attached vector of pointers to obj_cgroup objects, which is big enough to save a pointer for each allocated object. On the allocation, if the allocation has to be accounted (__GFP_ACCOUNT is passed, the allocating process belongs to a non-root memory cgroup, etc), the memory cgroup is getting charged and if the maximum limit is not exceeded the allocation is performed using a memcg-aware chunk. Otherwise -ENOMEM is returned or the allocation is forced over the limit, depending on gfp (as any other kernel memory allocation). The memory cgroup information is saved in the obj_cgroup vector at the corresponding offset. On the release time the memcg information is restored from the vector and the cgroup is getting uncharged. Unaccounted allocations (at this point the absolute majority of all percpu allocations) are performed in the old way, so no additional overhead is expected. To avoid pinning dying memory cgroups by outstanding allocations, obj_cgroup API is used instead of directly saving memory cgroup pointers. obj_cgroup is basically a pointer to a memory cgroup with a standalone reference counter. The trick is that it can be atomically swapped to point at the parent cgroup, so that the original memory cgroup can be released prior to all objects, which has been charged to it. Because all charges and statistics are fully recursive, it's perfectly correct to uncharge the parent cgroup instead. This scheme is used in the slab memory accounting, and percpu memory can just follow the scheme. This patch (of 5): To implement accounting of percpu memory we need the information about the size of freed object. Return it from pcpu_free_area(). Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Dennis Zhou <dennis@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Christoph Lameter <cl@linux.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Pekka Enberg <penberg@kernel.org> Cc: Tobin C. Harding <tobin@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Waiman Long <longman@redhat.com> cC: Michal Koutnýutny@suse.com> Cc: Bixuan Cui <cuibixuan@huawei.com> Cc: Michal Koutný <mkoutny@suse.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Link: http://lkml.kernel.org/r/20200623184515.4132564-1-guro@fb.com Link: http://lkml.kernel.org/r/20200608230819.832349-1-guro@fb.com Link: http://lkml.kernel.org/r/20200608230819.832349-2-guro@fb.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
Linus Torvalds
|
00e4db5125 |
perf tools changes for v5.9
New features:
- Introduce controlling how 'perf stat' and 'perf record' works via a
control file descriptor, allowing starting with events configured but
disabled until commands are received via the control file descriptor.
This allows, for instance for tools such as Intel VTune to make further
use of perf as its Linux platform driver.
- Improve 'perf record' to to register in a perf.data file header the clockid
used to help later correlate things like syslog files and perf events
recorded.
- Add basic syscall and find_next_bit benchmarks to 'perf bench'.
- Allow using computed metrics in calculating other metrics. For instance:
{
.metric_expr = "l2_rqsts.demand_data_rd_hit + l2_rqsts.pf_hit + l2_rqsts.rfo_hit",
.metric_name = "DCache_L2_All_Hits",
},
{
.metric_expr = "max(l2_rqsts.all_demand_data_rd - l2_rqsts.demand_data_rd_hit, 0) + l2_rqsts.pf_miss + l2_rqsts.rfo_miss",
.metric_name = "DCache_L2_All_Miss",
},
{
.metric_expr = "dcache_l2_all_hits + dcache_l2_all_miss",
.metric_name = "DCache_L2_All",
}
- Add suport for 'd_ratio', '>' and '<' operators to the expression resolver used
in calculating metrics in 'perf stat'.
Support for new kernel features:
- Support TEXT_POKE and KSYMBOL_TYPE_OOL perf metadata events to cope with
things like ftrace, trampolines, i.e. changes in the kernel text that gets
in the way of properly decoding Intel PT hardware traces, for instance.
Intel PT:
- Add various knobs to reduce the volume of Intel PT traces by reducing the
level of details such as decoding just some types of packets (e.g., FUP/TIP,
PSB+), also filtering by time range.
- Add new itrace options (log flags to the 'd' option, error flags to the 'e'
one, etc), controlling how Intel PT is transformed into perf events, document
some missing options (e.g., how to synthesize callchains).
BPF:
- Properly report BPF errors when parsing events.
- Do not setup side-band events if LIBBPF is not linked, fixing a segfault.
Libraries:
- Improvements on the libtraceevent plugin mechanism.
- Improve libtracevent support for KVM trace events SVM exit reasons.
- Add a libtracevent plugins for decoding syscalls/sys_enter_futex and for tlb_flush.
- Ensure sample_period is set libpfm4 events in 'perf test'.
- Fixup libperf namespacing, to make sure what is in libperf has the perf_
namespace while what is now only in tools/perf/ doesn't use that prefix.
Arch specific:
- Improve the testing of vendor events and metrics in 'perf test'.
- Allow no ARM CoreSight hardware tracer sink to be specified on command line.
- Fix arm_spe_x recording when mixed with other perf events.
- Add s390 idle functions 'psw_idle' and 'psw_idle_exit' to list of idle symbols.
- List kernel supplied event aliases for arm64 in 'perf list'.
- Add support for extended register capability in PowerPC 9 and 10.
- Added nest IMC power9 metric events.
Miscellaneous:
- No need to setup sample_regs_intr/sample_regs_user for dummy events.
- Update various copies of kernel headers, some causing perf to handle new
syscalls, MSRs, etc.
- Improve usage of flex and yacc, enabling warnings and addressing the fallout.
- Add missing '--output' option to 'perf kmem' so that it can pass it along to 'perf record'.
- 'perf probe' fixes related to adding multiple probes on the same address for
the same event.
- Make 'perf probe' warn if the target function is a GNU indirect function.
- Remove //anon mmap events from 'perf inject jit' to fix supporting both using
ELF files for generated functions and the perf-PID.map approaches.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Test results:
The first ones are container based builds of tools/perf with and without libelf
support. Where clang is available, it is also used to build perf with/without
libelf, and building with LIBCLANGLLVM=1 (built-in clang) with gcc and clang
when clang and its devel libraries are installed.
The objtool and samples/bpf/ builds are disabled now that I'm switching from
using the sources in a local volume to fetching them from a http server to
build it inside the container, to make it easier to build in a container cluster.
Those will come back later.
Several are cross builds, the ones with -x-ARCH and the android one, and those
may not have all the features built, due to lack of multi-arch devel packages,
available and being used so far on just a few, like
debian:experimental-x-{arm64,mipsel}.
The 'perf test' one will perform a variety of tests exercising
tools/perf/util/, tools/lib/{bpf,traceevent,etc}, as well as run perf commands
with a variety of command line event specifications to then intercept the
sys_perf_event syscall to check that the perf_event_attr fields are set up as
expected, among a variety of other unit tests.
Then there is the 'make -C tools/perf build-test' ones, that build tools/perf/
with a variety of feature sets, exercising the build with an incomplete set of
features as well as with a complete one. It is planned to have it run on each
of the containers mentioned above, using some container orchestration
infrastructure. Get in contact if interested in helping having this in place.
fedora:rawhide with python3 and gcc 10.1.1-2 is failing (10.1.1-1 on fedora:32
works), fixes will be provided soon.
clearlinux:latest is failing on libbpf, there is a fix already in the bpf tree.
The ones failing when linking with libllvm, not the default build, were
restricted to clang-9/llvm-9, working with anything before or after, e.g.,
using clang-8 on ubuntu:19.10 and clang-11 on debian:experimental fixed the
build in those environments.
# export PERF_TARBALL=http://192.168.124.1/perf/perf-5.8.0.tar.xz
# dm
1 alpine:3.4 : Ok gcc (Alpine 5.3.0) 5.3.0, clang version 3.8.0 (tags/RELEASE_380/final)
2 alpine:3.5 : Ok gcc (Alpine 6.2.1) 6.2.1 20160822, clang version 3.8.1 (tags/RELEASE_381/final)
3 alpine:3.6 : Ok gcc (Alpine 6.3.0) 6.3.0, clang version 4.0.0 (tags/RELEASE_400/final)
4 alpine:3.7 : Ok gcc (Alpine 6.4.0) 6.4.0, Alpine clang version 5.0.0 (tags/RELEASE_500/final) (based on LLVM 5.0.0)
5 alpine:3.8 : Ok gcc (Alpine 6.4.0) 6.4.0, Alpine clang version 5.0.1 (tags/RELEASE_501/final) (based on LLVM 5.0.1)
6 alpine:3.9 : Ok gcc (Alpine 8.3.0) 8.3.0, Alpine clang version 5.0.1 (tags/RELEASE_502/final) (based on LLVM 5.0.1)
7 alpine:3.10 : Ok gcc (Alpine 8.3.0) 8.3.0, Alpine clang version 8.0.0 (tags/RELEASE_800/final) (based on LLVM 8.0.0)
8 alpine:3.11 : Ok gcc (Alpine 9.2.0) 9.2.0, Alpine clang version 9.0.0 (https://git.alpinelinux.org/aports f7f0d2c2b8bcd6a5843401a9a702029556492689) (based on LLVM 9.0.0)
9 alpine:3.12 : Ok gcc (Alpine 9.3.0) 9.3.0, Alpine clang version 10.0.0 (https://gitlab.alpinelinux.org/alpine/aports.git 7445adce501f8473efdb93b17b5eaf2f1445ed4c)
10 alpine:edge : Ok gcc (Alpine 9.3.0) 9.3.0, Alpine clang version 10.0.0 (git://git.alpinelinux.org/aports 7445adce501f8473efdb93b17b5eaf2f1445ed4c)
11 alt:p8 : Ok x86_64-alt-linux-gcc (GCC) 5.3.1 20151207 (ALT p8 5.3.1-alt3.M80P.1), clang version 3.8.0 (tags/RELEASE_380/final)
12 alt:p9 : Ok x86_64-alt-linux-gcc (GCC) 8.4.1 20200305 (ALT p9 8.4.1-alt0.p9.1), clang version 7.0.1
13 alt:sisyphus : Ok x86_64-alt-linux-gcc (GCC) 9.2.1 20200123 (ALT Sisyphus 9.2.1-alt3), clang version 10.0.0
14 amazonlinux:1 : Ok gcc (GCC) 7.2.1 20170915 (Red Hat 7.2.1-2), clang version 3.6.2 (tags/RELEASE_362/final)
15 amazonlinux:2 : Ok gcc (GCC) 7.3.1 20180712 (Red Hat 7.3.1-6), clang version 7.0.1 (Amazon Linux 2 7.0.1-1.amzn2.0.2)
16 android-ndk:r12b-arm : Ok arm-linux-androideabi-gcc (GCC) 4.9.x 20150123 (prerelease)
17 android-ndk:r15c-arm : Ok arm-linux-androideabi-gcc (GCC) 4.9.x 20150123 (prerelease)
18 centos:6 : Ok gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-23)
19 centos:7 : Ok gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-39)
20 centos:8 : Ok gcc (GCC) 8.3.1 20191121 (Red Hat 8.3.1-5), clang version 9.0.1 (Red Hat 9.0.1-2.module_el8.2.0+309+0c7b6b03)
21 clearlinux:latest : FAIL gcc (Clear Linux OS for Intel Architecture) 10.2.1 20200723 releases/gcc-10.2.0-3-g677b80db41, clang version 10.0.1
gcc (Clear Linux OS for Intel Architecture) 10.2.1 20200723 releases/gcc-10.2.0-3-g677b80db41
btf.c: In function 'btf__parse_raw':
btf.c:625:28: error: 'btf' may be used uninitialized in this function [-Werror=maybe-uninitialized]
625 | return err ? ERR_PTR(err) : btf;
| ~~~~~~~~~~~~~~~~~~~^~~~~
22 debian:8 : Ok gcc (Debian 4.9.2-10+deb8u2) 4.9.2, Debian clang version 3.5.0-10 (tags/RELEASE_350/final) (based on LLVM 3.5.0)
23 debian:9 : Ok gcc (Debian 6.3.0-18+deb9u1) 6.3.0 20170516, clang version 3.8.1-24 (tags/RELEASE_381/final)
24 debian:10 : Ok gcc (Debian 8.3.0-6) 8.3.0, clang version 7.0.1-8 (tags/RELEASE_701/final)
25 debian:experimental : Ok gcc (Debian 10.2.0-3) 10.2.0, Debian clang version 11.0.0-+rc1-1
26 debian:experimental-x-arm64 : Ok aarch64-linux-gnu-gcc (Debian 9.3.0-8) 9.3.0
27 debian:experimental-x-mips : Ok mips-linux-gnu-gcc (Debian 8.3.0-19) 8.3.0
28 debian:experimental-x-mips64 : Ok mips64-linux-gnuabi64-gcc (Debian 9.3.0-8) 9.3.0
29 debian:experimental-x-mipsel : Ok mipsel-linux-gnu-gcc (Debian 9.2.1-8) 9.2.1 20190909
30 fedora:20 : Ok gcc (GCC) 4.8.3 20140911 (Red Hat 4.8.3-7)
31 fedora:22 : Ok gcc (GCC) 5.3.1 20160406 (Red Hat 5.3.1-6), clang version 3.5.0 (tags/RELEASE_350/final)
32 fedora:23 : Ok gcc (GCC) 5.3.1 20160406 (Red Hat 5.3.1-6), clang version 3.7.0 (tags/RELEASE_370/final)
33 fedora:24 : Ok gcc (GCC) 6.3.1 20161221 (Red Hat 6.3.1-1), clang version 3.8.1 (tags/RELEASE_381/final)
34 fedora:24-x-ARC-uClibc : Ok arc-linux-gcc (ARCompact ISA Linux uClibc toolchain 2017.09-rc2) 7.1.1 20170710
35 fedora:25 : Ok gcc (GCC) 6.4.1 20170727 (Red Hat 6.4.1-1), clang version 3.9.1 (tags/RELEASE_391/final)
36 fedora:26 : Ok gcc (GCC) 7.3.1 20180130 (Red Hat 7.3.1-2), clang version 4.0.1 (tags/RELEASE_401/final)
37 fedora:27 : Ok gcc (GCC) 7.3.1 20180712 (Red Hat 7.3.1-6), clang version 5.0.2 (tags/RELEASE_502/final)
38 fedora:28 : Ok gcc (GCC) 8.3.1 20190223 (Red Hat 8.3.1-2), clang version 6.0.1 (tags/RELEASE_601/final)
39 fedora:29 : Ok gcc (GCC) 8.3.1 20190223 (Red Hat 8.3.1-2), clang version 7.0.1 (Fedora 7.0.1-6.fc29)
40 fedora:30 : Ok gcc (GCC) 9.3.1 20200408 (Red Hat 9.3.1-2), clang version 8.0.0 (Fedora 8.0.0-3.fc30)
41 fedora:30-x-ARC-glibc : Ok arc-linux-gcc (ARC HS GNU/Linux glibc toolchain 2019.03-rc1) 8.3.1 20190225
42 fedora:30-x-ARC-uClibc : Ok arc-linux-gcc (ARCv2 ISA Linux uClibc toolchain 2019.03-rc1) 8.3.1 20190225
43 fedora:31 : Ok gcc (GCC) 9.3.1 20200408 (Red Hat 9.3.1-2), clang version 9.0.1 (Fedora 9.0.1-2.fc31)
44 fedora:32 : Ok gcc (GCC) 10.1.1 20200507 (Red Hat 10.1.1-1), clang version 10.0.0 (Fedora 10.0.0-2.fc32)
45 fedora:rawhide : FAIL gcc (GCC) 10.2.1 20200723 (Red Hat 10.2.1-1), clang version 10.0.0 (Fedora 10.0.0-10.fc33)
gcc (GCC) 10.2.1 20200723 (Red Hat 10.2.1-1)
util/scripting-engines/trace-event-python.c: In function 'python_start_script':
util/scripting-engines/trace-event-python.c:1595:2: error: 'visibility' attribute ignored [-Werror=attributes]
1595 | PyMODINIT_FUNC (*initfunc)(void);
| ^~~~~~~~~~~~~~
46 gentoo-stage3-amd64:latest : Ok gcc (Gentoo 9.3.0-r1 p3) 9.3.0
47 mageia:5 : Ok gcc (GCC) 4.9.2, clang version 3.5.2 (tags/RELEASE_352/final)
48 mageia:6 : Ok gcc (Mageia 5.5.0-1.mga6) 5.5.0, clang version 3.9.1 (tags/RELEASE_391/final)
49 mageia:7 : Ok gcc (Mageia 8.3.1-0.20190524.1.mga7) 8.3.1 20190524, clang version 8.0.0 (Mageia 8.0.0-1.mga7)
50 manjaro:latest : Ok gcc (GCC) 9.2.0, clang version 9.0.0 (tags/RELEASE_900/final)
51 openmandriva:cooker : Ok gcc (GCC) 10.0.0 20200502 (OpenMandriva), clang version 10.0.1
52 opensuse:15.0 : Ok gcc (SUSE Linux) 7.4.1 20190424 [gcc-7-branch revision 270538], clang version 5.0.1 (tags/RELEASE_501/final 312548)
53 opensuse:15.1 : Ok gcc (SUSE Linux) 7.5.0, clang version 7.0.1 (tags/RELEASE_701/final 349238)
54 opensuse:15.2 : Ok gcc (SUSE Linux) 7.5.0, clang version 9.0.1
55 opensuse:42.3 : Ok gcc (SUSE Linux) 4.8.5, clang version 3.8.0 (tags/RELEASE_380/final 262553)
56 opensuse:tumbleweed : Ok gcc (SUSE Linux) 10.2.1 20200728 [revision c0438ced53bcf57e4ebb1c38c226e41571aca892], clang version 10.0.1
57 oraclelinux:6 : Ok gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-23.0.1)
58 oraclelinux:7 : Ok gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-39.0.5)
59 oraclelinux:8 : Ok gcc (GCC) 8.3.1 20191121 (Red Hat 8.3.1-5.0.3), clang version 9.0.1 (Red Hat 9.0.1-2.0.1.module+el8.2.0+5599+9ed9ef6d)
60 ubuntu:12.04 : Ok gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3, Ubuntu clang version 3.0-6ubuntu3 (tags/RELEASE_30/final) (based on LLVM 3.0)
61 ubuntu:14.04 : Ok gcc (Ubuntu 4.8.4-2ubuntu1~14.04.4) 4.8.4
62 ubuntu:16.04 : Ok gcc (Ubuntu 5.4.0-6ubuntu1~16.04.12) 5.4.0 20160609, clang version 3.8.0-2ubuntu4 (tags/RELEASE_380/final)
63 ubuntu:16.04-x-arm : Ok arm-linux-gnueabihf-gcc (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
64 ubuntu:16.04-x-arm64 : Ok aarch64-linux-gnu-gcc (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
65 ubuntu:16.04-x-powerpc : Ok powerpc-linux-gnu-gcc (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
66 ubuntu:16.04-x-powerpc64 : Ok powerpc64-linux-gnu-gcc (Ubuntu/IBM 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
67 ubuntu:16.04-x-powerpc64el : Ok powerpc64le-linux-gnu-gcc (Ubuntu/IBM 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
68 ubuntu:16.04-x-s390 : Ok s390x-linux-gnu-gcc (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
69 ubuntu:18.04 : Ok gcc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0, clang version 6.0.0-1ubuntu2 (tags/RELEASE_600/final)
70 ubuntu:18.04-x-arm : Ok arm-linux-gnueabihf-gcc (Ubuntu/Linaro 7.5.0-3ubuntu1~18.04) 7.5.0
71 ubuntu:18.04-x-arm64 : Ok aarch64-linux-gnu-gcc (Ubuntu/Linaro 7.5.0-3ubuntu1~18.04) 7.5.0
72 ubuntu:18.04-x-m68k : Ok m68k-linux-gnu-gcc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0
73 ubuntu:18.04-x-powerpc : Ok powerpc-linux-gnu-gcc (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0
74 ubuntu:18.04-x-powerpc64 : Ok powerpc64-linux-gnu-gcc (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0
75 ubuntu:18.04-x-powerpc64el : Ok powerpc64le-linux-gnu-gcc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0
76 ubuntu:18.04-x-riscv64 : Ok riscv64-linux-gnu-gcc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0
77 ubuntu:18.04-x-s390 : Ok s390x-linux-gnu-gcc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0
78 ubuntu:18.04-x-sh4 : Ok sh4-linux-gnu-gcc (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0
79 ubuntu:18.04-x-sparc64 : Ok sparc64-linux-gnu-gcc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0
80 ubuntu:18.10 : Ok gcc (Ubuntu 8.3.0-6ubuntu1~18.10.1) 8.3.0, clang version 7.0.0-3 (tags/RELEASE_700/final)
81 ubuntu:19.04 : Ok gcc (Ubuntu 8.3.0-6ubuntu1) 8.3.0, clang version 8.0.0-3 (tags/RELEASE_800/final)
82 ubuntu:19.04-x-alpha : Ok alpha-linux-gnu-gcc (Ubuntu 8.3.0-6ubuntu1) 8.3.0
83 ubuntu:19.04-x-arm64 : Ok aarch64-linux-gnu-gcc (Ubuntu/Linaro 8.3.0-6ubuntu1) 8.3.0
84 ubuntu:19.04-x-hppa : Ok hppa-linux-gnu-gcc (Ubuntu 8.3.0-6ubuntu1) 8.3.0
85 ubuntu:19.10 : Ok gcc (Ubuntu 9.2.1-9ubuntu2) 9.2.1 20191008, clang version 8.0.1-3build1 (tags/RELEASE_801/final)
86 219.74 ubuntu:20.04 : Ok gcc (Ubuntu 9.3.0-10ubuntu2) 9.3.0, clang version 10.0.0-4ubuntu1
#
# uname -a
Linux quaco 5.7.12-200.fc32.x86_64 #1 SMP Sat Aug 1 16:13:38 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
# git log --oneline -1
|
||
|
Linus Torvalds
|
ed3854ff99 |
Updates for ktest 5.9
- Have config-bisect save the good/bad configs at each step. - Show log file location even on success - Add PRE_TEST_DIE to kill test if the PRE_TEST fails - Add a NOT operator for conditionals in config file - Add the log output of the last test when emailing on failure. - Other minor clean ups and small fixes. -----BEGIN PGP SIGNATURE----- iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCXzH4tBQccm9zdGVkdEBn b29kbWlzLm9yZwAKCRAp5XQQmuv6qiTVAQCmZzxANHxg58CI4gKCMDmUb9PBoPru 9vIHnQzgr8YiMQEA9+UIuxQxSVT79ONABut56tlTksPqWYelpdkn+nrJAAE= =ilWu -----END PGP SIGNATURE----- Merge tag 'ktest-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-ktest Pull ktest updates from Steven Rostedt: - Have config-bisect save the good/bad configs at each step. - Show log file location even on success - Add PRE_TEST_DIE to kill test if the PRE_TEST fails - Add a NOT operator for conditionals in config file - Add the log output of the last test when emailing on failure. - Other minor clean ups and small fixes. * tag 'ktest-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-ktest: ktest.pl: Fix spelling mistake "Cant" -> "Can't" ktest.pl: Change the logic to control the size of the log file emailed ktest.pl: Add MAIL_MAX_SIZE to limit the amount of log emailed ktest.pl: Add the log of last test in email on failure ktest.pl: Turn off buffering to the log file ktest.pl: Just open up the log file once ktest.pl: Add a NOT operator ktest.pl: Define PRE_TEST_DIE to kill the test if the PRE_TEST fails ktest.pl: Always show log file location if defined even on success ktest.pl: Have config-bisect save each config used in the bisect |
||
|
Linus Torvalds
|
97d052ea3f |
A set of locking fixes and updates:
- Untangle the header spaghetti which causes build failures in various
situations caused by the lockdep additions to seqcount to validate that
the write side critical sections are non-preemptible.
- The seqcount associated lock debug addons which were blocked by the
above fallout.
seqcount writers contrary to seqlock writers must be externally
serialized, which usually happens via locking - except for strict per
CPU seqcounts. As the lock is not part of the seqcount, lockdep cannot
validate that the lock is held.
This new debug mechanism adds the concept of associated locks.
sequence count has now lock type variants and corresponding
initializers which take a pointer to the associated lock used for
writer serialization. If lockdep is enabled the pointer is stored and
write_seqcount_begin() has a lockdep assertion to validate that the
lock is held.
Aside of the type and the initializer no other code changes are
required at the seqcount usage sites. The rest of the seqcount API is
unchanged and determines the type at compile time with the help of
_Generic which is possible now that the minimal GCC version has been
moved up.
Adding this lockdep coverage unearthed a handful of seqcount bugs which
have been addressed already independent of this.
While generaly useful this comes with a Trojan Horse twist: On RT
kernels the write side critical section can become preemtible if the
writers are serialized by an associated lock, which leads to the well
known reader preempts writer livelock. RT prevents this by storing the
associated lock pointer independent of lockdep in the seqcount and
changing the reader side to block on the lock when a reader detects
that a writer is in the write side critical section.
- Conversion of seqcount usage sites to associated types and initializers.
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Merge tag 'locking-urgent-2020-08-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Thomas Gleixner:
"A set of locking fixes and updates:
- Untangle the header spaghetti which causes build failures in
various situations caused by the lockdep additions to seqcount to
validate that the write side critical sections are non-preemptible.
- The seqcount associated lock debug addons which were blocked by the
above fallout.
seqcount writers contrary to seqlock writers must be externally
serialized, which usually happens via locking - except for strict
per CPU seqcounts. As the lock is not part of the seqcount, lockdep
cannot validate that the lock is held.
This new debug mechanism adds the concept of associated locks.
sequence count has now lock type variants and corresponding
initializers which take a pointer to the associated lock used for
writer serialization. If lockdep is enabled the pointer is stored
and write_seqcount_begin() has a lockdep assertion to validate that
the lock is held.
Aside of the type and the initializer no other code changes are
required at the seqcount usage sites. The rest of the seqcount API
is unchanged and determines the type at compile time with the help
of _Generic which is possible now that the minimal GCC version has
been moved up.
Adding this lockdep coverage unearthed a handful of seqcount bugs
which have been addressed already independent of this.
While generally useful this comes with a Trojan Horse twist: On RT
kernels the write side critical section can become preemtible if
the writers are serialized by an associated lock, which leads to
the well known reader preempts writer livelock. RT prevents this by
storing the associated lock pointer independent of lockdep in the
seqcount and changing the reader side to block on the lock when a
reader detects that a writer is in the write side critical section.
- Conversion of seqcount usage sites to associated types and
initializers"
* tag 'locking-urgent-2020-08-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
locking/seqlock, headers: Untangle the spaghetti monster
locking, arch/ia64: Reduce <asm/smp.h> header dependencies by moving XTP bits into the new <asm/xtp.h> header
x86/headers: Remove APIC headers from <asm/smp.h>
seqcount: More consistent seqprop names
seqcount: Compress SEQCNT_LOCKNAME_ZERO()
seqlock: Fold seqcount_LOCKNAME_init() definition
seqlock: Fold seqcount_LOCKNAME_t definition
seqlock: s/__SEQ_LOCKDEP/__SEQ_LOCK/g
hrtimer: Use sequence counter with associated raw spinlock
kvm/eventfd: Use sequence counter with associated spinlock
userfaultfd: Use sequence counter with associated spinlock
NFSv4: Use sequence counter with associated spinlock
iocost: Use sequence counter with associated spinlock
raid5: Use sequence counter with associated spinlock
vfs: Use sequence counter with associated spinlock
timekeeping: Use sequence counter with associated raw spinlock
xfrm: policy: Use sequence counters with associated lock
netfilter: nft_set_rbtree: Use sequence counter with associated rwlock
netfilter: conntrack: Use sequence counter with associated spinlock
sched: tasks: Use sequence counter with associated spinlock
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