Michal Hocko d6507ff533 memcg: put soft limit reclaim out of way if the excess tree is empty ... We've had a report about soft lockups caused by lock bouncing in the soft reclaim path: BUG: soft lockup - CPU#0 stuck for 22s! [kav4proxy-kavic:3128] RIP: 0010:[<ffffffff81469798>] [<ffffffff81469798>] _raw_spin_lock+0x18/0x20 Call Trace: mem_cgroup_soft_limit_reclaim+0x25a/0x280 shrink_zones+0xed/0x200 do_try_to_free_pages+0x74/0x320 try_to_free_pages+0x112/0x180 __alloc_pages_slowpath+0x3ff/0x820 __alloc_pages_nodemask+0x1e9/0x200 alloc_pages_vma+0xe1/0x290 do_wp_page+0x19f/0x840 handle_pte_fault+0x1cd/0x230 do_page_fault+0x1fd/0x4c0 page_fault+0x25/0x30 There are no memcgs created so there cannot be any in the soft limit excess obviously: [...] memory 0 1 1 so all this just seems to be mem_cgroup_largest_soft_limit_node trying to get spin_lock_irq(&mctz->lock) just to find out that the soft limit excess tree is empty. This is just pointless wasting of cycles and cache line bouncing during heavy parallel reclaim on large machines. The particular machine wasn't very healthy and most probably suffering from a memory leak which just caused the memory reclaim to trash heavily. But bouncing on the lock certainly didn't help... Fix this by optimistic lockless check and bail out early if the tree is empty. This is theoretically racy but that shouldn't matter all that much. First of all soft limit is a best effort feature and it is slowly getting deprecated and its usage should be really scarce. Bouncing on a lock without a good reason is surely much bigger problem, especially on large CPU machines. Link: http://lkml.kernel.org/r/1470073277-1056-1-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com> 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>		2016-08-02 17:31:41 -04:00
..
kasan	mm, kasan: switch SLUB to stackdepot, enable memory quarantine for SLUB	2016-07-28 16:07:41 -07:00
backing-dev.c	mm, vmscan: move LRU lists to node	2016-07-28 16:07:41 -07:00
balloon_compaction.c	mm: balloon: use general non-lru movable page feature	2016-07-26 16:19:19 -07:00
bootmem.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
cleancache.c	cleancache: constify cleancache_ops structure	2016-01-27 09:09:57 -05:00
cma_debug.c
cma.c	mm/cma: silence warnings due to max() usage	2016-05-27 14:49:37 -07:00
cma.h
compaction.c	mm, compaction: simplify contended compaction handling	2016-07-28 16:07:41 -07:00
debug_page_ref.c	mm/page_ref: add tracepoint to track down page reference manipulation	2016-03-17 15:09:34 -07:00
debug.c	mm: introduce page reference manipulation functions	2016-03-17 15:09:34 -07:00
dmapool.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
early_ioremap.c	mm/early_ioremap: use offset_in_page macro	2015-11-05 19:34:48 -08:00
fadvise.c	mm/fadvise.c: do not discard partial pages with POSIX_FADV_DONTNEED	2016-06-09 14:23:11 -07:00
failslab.c	mm: fault-inject take over bootstrap kmem_cache check	2016-03-15 16:55:16 -07:00
filemap.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse	2016-07-29 12:29:15 -07:00
frame_vector.c	mm/gup: Switch all callers of get_user_pages() to not pass tsk/mm	2016-02-16 10:11:12 +01:00
frontswap.c	mm, frontswap: convert frontswap_enabled to static key	2016-07-26 16:19:19 -07:00
gup.c	thp: file pages support for split_huge_page()	2016-07-26 16:19:19 -07:00
highmem.c	mm/highmem: make nr_free_highpages() handles all highmem zones by itself	2016-05-19 19:12:14 -07:00
huge_memory.c	mm, thp: remove __GFP_NORETRY from khugepaged and madvised allocations	2016-07-28 16:07:41 -07:00
hugetlb_cgroup.c	mm, hugetlb_cgroup: round limit_in_bytes down to hugepage size	2016-05-20 17:58:30 -07:00
hugetlb.c	mm, hugetlb: fix huge_pte_alloc BUG_ON	2016-08-02 17:31:41 -04:00
hwpoison-inject.c
init-mm.c
internal.h	mm, compaction: simplify contended compaction handling	2016-07-28 16:07:41 -07:00
interval_tree.c
Kconfig	mm: CONFIG_ZONE_DEVICE stop depending on CONFIG_EXPERT	2016-07-28 16:07:41 -07:00
Kconfig.debug	mm/page_ref: add tracepoint to track down page reference manipulation	2016-03-17 15:09:34 -07:00
khugepaged.c	mm, thp: remove __GFP_NORETRY from khugepaged and madvised allocations	2016-07-28 16:07:41 -07:00
kmemcheck.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
kmemleak-test.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
kmemleak.c	kmemleak: don't hang if user disables scanning early	2016-07-28 16:07:41 -07:00
ksm.c	mm: do not pass mm_struct into handle_mm_fault	2016-07-26 16:19:19 -07:00
list_lru.c	mm: memcontrol: move kmem accounting code to CONFIG_MEMCG	2016-01-20 17:09:18 -08:00
maccess.c	x86: remove more uaccess_32.h complexity	2016-05-22 17:21:27 -07:00
madvise.c	mm: make mmap_sem for write waits killable for mm syscalls	2016-05-23 17:04:14 -07:00
Makefile	thp: extract khugepaged from mm/huge_memory.c	2016-07-26 16:19:19 -07:00
memblock.c	mm/memblock.c: fix index adjustment error in __next_mem_range_rev()	2016-07-28 16:07:41 -07:00
memcontrol.c	memcg: put soft limit reclaim out of way if the excess tree is empty	2016-08-02 17:31:41 -04:00
memory_hotplug.c	mem-hotplug: alloc new page from a nearest neighbor node when mem-offline	2016-07-28 16:07:41 -07:00
memory-failure.c	mm: hwpoison: remove incorrect comments	2016-07-28 16:07:41 -07:00
memory.c	mm: move swap-in anonymous page into active list	2016-08-02 17:31:41 -04:00
mempolicy.c	mm, vmscan: move LRU lists to node	2016-07-28 16:07:41 -07:00
mempool.c	Revert "mm, mempool: only set __GFP_NOMEMALLOC if there are free elements"	2016-07-28 16:07:41 -07:00
memtest.c
migrate.c	mm, thp: remove __GFP_NORETRY from khugepaged and madvised allocations	2016-07-28 16:07:41 -07:00
mincore.c	mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage	2016-04-04 10:41:08 -07:00
mlock.c	mm, vmscan: move LRU lists to node	2016-07-28 16:07:41 -07:00
mm_init.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
mmap.c	mm: fix use-after-free if memory allocation failed in vma_adjust()	2016-07-28 16:07:41 -07:00
mmu_context.c	mm/mmu_context, sched/core: Fix mmu_context.h assumption	2016-04-28 11:44:19 +02:00
mmu_notifier.c	fix Christoph's email addresses	2016-03-17 15:09:34 -07:00
mmzone.c	mm, page_alloc: inline the fast path of the zonelist iterator	2016-05-19 19:12:14 -07:00
mprotect.c	mm: thp: check pmd_trans_unstable() after split_huge_pmd()	2016-07-26 16:19:19 -07:00
mremap.c	mm: thp: check pmd_trans_unstable() after split_huge_pmd()	2016-07-26 16:19:19 -07:00
msync.c	mm/msync: use offset_in_page macro	2015-11-05 19:34:48 -08:00
nobootmem.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
nommu.c	mm: introduce fault_env	2016-07-26 16:19:19 -07:00
oom_kill.c	mm, oom: tighten task_will_free_mem() locking	2016-07-28 16:07:41 -07:00
page_alloc.c	mm, compaction: simplify contended compaction handling	2016-07-28 16:07:41 -07:00
page_counter.c	mm: page_counter: let page_counter_try_charge() return bool	2015-11-05 19:34:48 -08:00
page_ext.c	mm: use early_pfn_to_nid in page_ext_init	2016-05-27 14:49:37 -07:00
page_idle.c	mm, vmscan: move lru_lock to the node	2016-07-28 16:07:41 -07:00
page_io.c	mm: add cond_resched() to generic_swapfile_activate()	2016-07-28 16:07:41 -07:00
page_isolation.c	mm/page_isolation: clean up confused code	2016-07-26 16:19:19 -07:00
page_owner.c	mm/page_owner: use stackdepot to store stacktrace	2016-07-26 16:19:19 -07:00
page_poison.c	mm: check the return value of lookup_page_ext for all call sites	2016-06-03 15:06:22 -07:00
page-writeback.c	mm: remove reclaim and compaction retry approximations	2016-07-28 16:07:41 -07:00
pagewalk.c	thp: rename split_huge_page_pmd() to split_huge_pmd()	2016-01-15 17:56:32 -08:00
percpu-km.c	mm: percpu: use pr_fmt to prefix output	2016-03-17 15:09:34 -07:00
percpu-vm.c
percpu.c	percpu: fix synchronization between synchronous map extension and chunk destruction	2016-05-25 11:48:25 -04:00
pgtable-generic.c	mm/thp/migration: switch from flush_tlb_range to flush_pmd_tlb_range	2016-03-17 15:09:34 -07:00
process_vm_access.c	mm/gup: Introduce get_user_pages_remote()	2016-02-16 10:04:09 +01:00
quicklist.c	fix Christoph's email addresses	2016-03-17 15:09:34 -07:00
readahead.c	mm, memcg: use consistent gfp flags during readahead	2016-07-26 16:19:19 -07:00
rmap.c	mm: move most file-based accounting to the node	2016-07-28 16:07:41 -07:00
shmem.c	mm: move most file-based accounting to the node	2016-07-28 16:07:41 -07:00
slab_common.c	mm: charge/uncharge kmemcg from generic page allocator paths	2016-07-26 16:19:19 -07:00
slab.c	mm/slab: use list_move instead of list_del/list_add	2016-07-26 16:19:19 -07:00
slab.h	mm, kasan: switch SLUB to stackdepot, enable memory quarantine for SLUB	2016-07-28 16:07:41 -07:00
slob.c	mm: slab: free kmem_cache_node after destroy sysfs file	2016-02-18 16:23:24 -08:00
slub.c	mm, kasan: switch SLUB to stackdepot, enable memory quarantine for SLUB	2016-07-28 16:07:41 -07:00
sparse-vmemmap.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
sparse.c	make __section_nr() more efficient	2016-07-28 16:07:41 -07:00
swap_cgroup.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
swap_state.c	mm: move most file-based accounting to the node	2016-07-28 16:07:41 -07:00
swap.c	mm, pagevec: release/reacquire lru_lock on pgdat change	2016-07-28 16:07:41 -07:00
swapfile.c	mm, frontswap: convert frontswap_enabled to static key	2016-07-26 16:19:19 -07:00
truncate.c	truncate: handle file thp	2016-07-26 16:19:19 -07:00
userfaultfd.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00
util.c	mm: move most file-based accounting to the node	2016-07-28 16:07:41 -07:00
vmacache.c	mm/vmacache: inline vmacache_valid_mm()	2015-11-05 19:34:48 -08:00
vmalloc.c	mm: charge/uncharge kmemcg from generic page allocator paths	2016-07-26 16:19:19 -07:00
vmpressure.c	mm/vmpressure.c: fix subtree pressure detection	2016-02-03 08:28:43 -08:00
vmscan.c	mm: bail out in shrink_inactive_list()	2016-07-28 16:07:41 -07:00
vmstat.c	mm: remove reclaim and compaction retry approximations	2016-07-28 16:07:41 -07:00
workingset.c	mm, workingset: make working set detection node-aware	2016-07-28 16:07:41 -07:00
z3fold.c	mm/z3fold.c: avoid modifying HEADLESS page and minor cleanup	2016-06-03 16:02:55 -07:00
zbud.c	mm/zbud.c: use list_last_entry() instead of list_tail_entry()	2016-01-15 11:40:52 -08:00
zpool.c	mm: zsmalloc: constify struct zs_pool name	2015-11-06 17:50:42 -08:00
zsmalloc.c	zsmalloc: Delete an unnecessary check before the function call "iput"	2016-07-28 16:07:41 -07:00
zswap.c	mm/zswap: use workqueue to destroy pool	2016-05-20 17:58:30 -07:00