From ecf5fc6e9654cd7a268c782a523f072b2f1959f9 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Tue, 4 Aug 2015 14:36:58 -0700 Subject: mm, vmscan: Do not wait for page writeback for GFP_NOFS allocations Nikolay has reported a hang when a memcg reclaim got stuck with the following backtrace: PID: 18308 TASK: ffff883d7c9b0a30 CPU: 1 COMMAND: "rsync" #0 __schedule at ffffffff815ab152 #1 schedule at ffffffff815ab76e #2 schedule_timeout at ffffffff815ae5e5 #3 io_schedule_timeout at ffffffff815aad6a #4 bit_wait_io at ffffffff815abfc6 #5 __wait_on_bit at ffffffff815abda5 #6 wait_on_page_bit at ffffffff8111fd4f #7 shrink_page_list at ffffffff81135445 #8 shrink_inactive_list at ffffffff81135845 #9 shrink_lruvec at ffffffff81135ead #10 shrink_zone at ffffffff811360c3 #11 shrink_zones at ffffffff81136eff #12 do_try_to_free_pages at ffffffff8113712f #13 try_to_free_mem_cgroup_pages at ffffffff811372be #14 try_charge at ffffffff81189423 #15 mem_cgroup_try_charge at ffffffff8118c6f5 #16 __add_to_page_cache_locked at ffffffff8112137d #17 add_to_page_cache_lru at ffffffff81121618 #18 pagecache_get_page at ffffffff8112170b #19 grow_dev_page at ffffffff811c8297 #20 __getblk_slow at ffffffff811c91d6 #21 __getblk_gfp at ffffffff811c92c1 #22 ext4_ext_grow_indepth at ffffffff8124565c #23 ext4_ext_create_new_leaf at ffffffff81246ca8 #24 ext4_ext_insert_extent at ffffffff81246f09 #25 ext4_ext_map_blocks at ffffffff8124a848 #26 ext4_map_blocks at ffffffff8121a5b7 #27 mpage_map_one_extent at ffffffff8121b1fa #28 mpage_map_and_submit_extent at ffffffff8121f07b #29 ext4_writepages at ffffffff8121f6d5 #30 do_writepages at ffffffff8112c490 #31 __filemap_fdatawrite_range at ffffffff81120199 #32 filemap_flush at ffffffff8112041c #33 ext4_alloc_da_blocks at ffffffff81219da1 #34 ext4_rename at ffffffff81229b91 #35 ext4_rename2 at ffffffff81229e32 #36 vfs_rename at ffffffff811a08a5 #37 SYSC_renameat2 at ffffffff811a3ffc #38 sys_renameat2 at ffffffff811a408e #39 sys_rename at ffffffff8119e51e #40 system_call_fastpath at ffffffff815afa89 Dave Chinner has properly pointed out that this is a deadlock in the reclaim code because ext4 doesn't submit pages which are marked by PG_writeback right away. The heuristic was introduced by commit e62e384e9da8 ("memcg: prevent OOM with too many dirty pages") and it was applied only when may_enter_fs was specified. The code has been changed by c3b94f44fcb0 ("memcg: further prevent OOM with too many dirty pages") which has removed the __GFP_FS restriction with a reasoning that we do not get into the fs code. But this is not sufficient apparently because the fs doesn't necessarily submit pages marked PG_writeback for IO right away. ext4_bio_write_page calls io_submit_add_bh but that doesn't necessarily submit the bio. Instead it tries to map more pages into the bio and mpage_map_one_extent might trigger memcg charge which might end up waiting on a page which is marked PG_writeback but hasn't been submitted yet so we would end up waiting for something that never finishes. Fix this issue by replacing __GFP_IO by may_enter_fs check (for case 2) before we go to wait on the writeback. The page fault path, which is the only path that triggers memcg oom killer since 3.12, shouldn't require GFP_NOFS and so we shouldn't reintroduce the premature OOM killer issue which was originally addressed by the heuristic. As per David Chinner the xfs is doing similar thing since 2.6.15 already so ext4 is not the only affected filesystem. Moreover he notes: : For example: IO completion might require unwritten extent conversion : which executes filesystem transactions and GFP_NOFS allocations. The : writeback flag on the pages can not be cleared until unwritten : extent conversion completes. Hence memory reclaim cannot wait on : page writeback to complete in GFP_NOFS context because it is not : safe to do so, memcg reclaim or otherwise. Cc: stable@vger.kernel.org # 3.9+ [tytso@mit.edu: corrected the control flow] Fixes: c3b94f44fcb0 ("memcg: further prevent OOM with too many dirty pages") Reported-by: Nikolay Borisov Signed-off-by: Michal Hocko Signed-off-by: Hugh Dickins Signed-off-by: Linus Torvalds --- mm/vmscan.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) (limited to 'mm/vmscan.c') diff --git a/mm/vmscan.c b/mm/vmscan.c index e61445dce04e..8286938c70de 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -973,22 +973,18 @@ static unsigned long shrink_page_list(struct list_head *page_list, * caller can stall after page list has been processed. * * 2) Global or new memcg reclaim encounters a page that is - * not marked for immediate reclaim or the caller does not - * have __GFP_IO. In this case mark the page for immediate + * not marked for immediate reclaim, or the caller does not + * have __GFP_FS (or __GFP_IO if it's simply going to swap, + * not to fs). In this case mark the page for immediate * reclaim and continue scanning. * - * __GFP_IO is checked because a loop driver thread might + * Require may_enter_fs because we would wait on fs, which + * may not have submitted IO yet. And the loop driver might * enter reclaim, and deadlock if it waits on a page for * which it is needed to do the write (loop masks off * __GFP_IO|__GFP_FS for this reason); but more thought * would probably show more reasons. * - * Don't require __GFP_FS, since we're not going into the - * FS, just waiting on its writeback completion. Worryingly, - * ext4 gfs2 and xfs allocate pages with - * grab_cache_page_write_begin(,,AOP_FLAG_NOFS), so testing - * may_enter_fs here is liable to OOM on them. - * * 3) Legacy memcg encounters a page that is not already marked * PageReclaim. memcg does not have any dirty pages * throttling so we could easily OOM just because too many @@ -1005,7 +1001,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, /* Case 2 above */ } else if (sane_reclaim(sc) || - !PageReclaim(page) || !(sc->gfp_mask & __GFP_IO)) { + !PageReclaim(page) || !may_enter_fs) { /* * This is slightly racy - end_page_writeback() * might have just cleared PageReclaim, then -- cgit v1.2.3-70-g09d2 From 72b252aed506b8f1a03f7abd29caef4cdf6a043b Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Fri, 4 Sep 2015 15:47:32 -0700 Subject: mm: send one IPI per CPU to TLB flush all entries after unmapping pages An IPI is sent to flush remote TLBs when a page is unmapped that was potentially accesssed by other CPUs. There are many circumstances where this happens but the obvious one is kswapd reclaiming pages belonging to a running process as kswapd and the task are likely running on separate CPUs. On small machines, this is not a significant problem but as machine gets larger with more cores and more memory, the cost of these IPIs can be high. This patch uses a simple structure that tracks CPUs that potentially have TLB entries for pages being unmapped. When the unmapping is complete, the full TLB is flushed on the assumption that a refill cost is lower than flushing individual entries. Architectures wishing to do this must give the following guarantee. If a clean page is unmapped and not immediately flushed, the architecture must guarantee that a write to that linear address from a CPU with a cached TLB entry will trap a page fault. This is essentially what the kernel already depends on but the window is much larger with this patch applied and is worth highlighting. The architecture should consider whether the cost of the full TLB flush is higher than sending an IPI to flush each individual entry. An additional architecture helper called flush_tlb_local is required. It's a trivial wrapper with some accounting in the x86 case. The impact of this patch depends on the workload as measuring any benefit requires both mapped pages co-located on the LRU and memory pressure. The case with the biggest impact is multiple processes reading mapped pages taken from the vm-scalability test suite. The test case uses NR_CPU readers of mapped files that consume 10*RAM. Linear mapped reader on a 4-node machine with 64G RAM and 48 CPUs 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 Ops lru-file-mmap-read-elapsed 159.62 ( 0.00%) 120.68 ( 24.40%) Ops lru-file-mmap-read-time_range 30.59 ( 0.00%) 2.80 ( 90.85%) Ops lru-file-mmap-read-time_stddv 6.70 ( 0.00%) 0.64 ( 90.38%) 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 User 581.00 611.43 System 5804.93 4111.76 Elapsed 161.03 122.12 This is showing that the readers completed 24.40% faster with 29% less system CPU time. From vmstats, it is known that the vanilla kernel was interrupted roughly 900K times per second during the steady phase of the test and the patched kernel was interrupts 180K times per second. The impact is lower on a single socket machine. 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 Ops lru-file-mmap-read-elapsed 25.33 ( 0.00%) 20.38 ( 19.54%) Ops lru-file-mmap-read-time_range 0.91 ( 0.00%) 1.44 (-58.24%) Ops lru-file-mmap-read-time_stddv 0.28 ( 0.00%) 0.47 (-65.34%) 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 User 58.09 57.64 System 111.82 76.56 Elapsed 27.29 22.55 It's still a noticeable improvement with vmstat showing interrupts went from roughly 500K per second to 45K per second. The patch will have no impact on workloads with no memory pressure or have relatively few mapped pages. It will have an unpredictable impact on the workload running on the CPU being flushed as it'll depend on how many TLB entries need to be refilled and how long that takes. Worst case, the TLB will be completely cleared of active entries when the target PFNs were not resident at all. [sasha.levin@oracle.com: trace tlb flush after disabling preemption in try_to_unmap_flush] Signed-off-by: Mel Gorman Reviewed-by: Rik van Riel Cc: Dave Hansen Acked-by: Ingo Molnar Cc: Linus Torvalds Signed-off-by: Sasha Levin Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86/Kconfig | 1 + arch/x86/include/asm/tlbflush.h | 6 +++ include/linux/rmap.h | 3 ++ include/linux/sched.h | 16 +++++++ init/Kconfig | 10 ++++ mm/internal.h | 11 +++++ mm/rmap.c | 104 +++++++++++++++++++++++++++++++++++++++- mm/vmscan.c | 23 ++++++++- 8 files changed, 172 insertions(+), 2 deletions(-) (limited to 'mm/vmscan.c') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 48f7433dac6f..117e2f373e50 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -41,6 +41,7 @@ config X86 select ARCH_USE_CMPXCHG_LOCKREF if X86_64 select ARCH_USE_QUEUED_RWLOCKS select ARCH_USE_QUEUED_SPINLOCKS + select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if SMP select ARCH_WANTS_DYNAMIC_TASK_STRUCT select ARCH_WANT_FRAME_POINTERS select ARCH_WANT_IPC_PARSE_VERSION if X86_32 diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index cd791948b286..6df2029405a3 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -261,6 +261,12 @@ static inline void reset_lazy_tlbstate(void) #endif /* SMP */ +/* Not inlined due to inc_irq_stat not being defined yet */ +#define flush_tlb_local() { \ + inc_irq_stat(irq_tlb_count); \ + local_flush_tlb(); \ +} + #ifndef CONFIG_PARAVIRT #define flush_tlb_others(mask, mm, start, end) \ native_flush_tlb_others(mask, mm, start, end) diff --git a/include/linux/rmap.h b/include/linux/rmap.h index c89c53a113a8..29446aeef36e 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -89,6 +89,9 @@ enum ttu_flags { TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */ TTU_IGNORE_ACCESS = (1 << 9), /* don't age */ TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */ + TTU_BATCH_FLUSH = (1 << 11), /* Batch TLB flushes where possible + * and caller guarantees they will + * do a final flush if necessary */ }; #ifdef CONFIG_MMU diff --git a/include/linux/sched.h b/include/linux/sched.h index 119823decc46..3c602c20c717 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1344,6 +1344,18 @@ enum perf_event_task_context { perf_nr_task_contexts, }; +/* Track pages that require TLB flushes */ +struct tlbflush_unmap_batch { + /* + * Each bit set is a CPU that potentially has a TLB entry for one of + * the PFNs being flushed. See set_tlb_ubc_flush_pending(). + */ + struct cpumask cpumask; + + /* True if any bit in cpumask is set */ + bool flush_required; +}; + struct task_struct { volatile long state; /* -1 unrunnable, 0 runnable, >0 stopped */ void *stack; @@ -1700,6 +1712,10 @@ struct task_struct { unsigned long numa_pages_migrated; #endif /* CONFIG_NUMA_BALANCING */ +#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH + struct tlbflush_unmap_batch tlb_ubc; +#endif + struct rcu_head rcu; /* diff --git a/init/Kconfig b/init/Kconfig index 161acd8bc56f..cf7e4824c8d0 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -882,6 +882,16 @@ config GENERIC_SCHED_CLOCK config ARCH_SUPPORTS_NUMA_BALANCING bool +# +# For architectures that prefer to flush all TLBs after a number of pages +# are unmapped instead of sending one IPI per page to flush. The architecture +# must provide guarantees on what happens if a clean TLB cache entry is +# written after the unmap. Details are in mm/rmap.c near the check for +# should_defer_flush. The architecture should also consider if the full flush +# and the refill costs are offset by the savings of sending fewer IPIs. +config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH + bool + # # For architectures that know their GCC __int128 support is sound # diff --git a/mm/internal.h b/mm/internal.h index 36b23f1e2ca6..bd6372ac5f7f 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -426,4 +426,15 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone, #define ALLOC_CMA 0x80 /* allow allocations from CMA areas */ #define ALLOC_FAIR 0x100 /* fair zone allocation */ +enum ttu_flags; +struct tlbflush_unmap_batch; + +#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH +void try_to_unmap_flush(void); +#else +static inline void try_to_unmap_flush(void) +{ +} + +#endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */ #endif /* __MM_INTERNAL_H */ diff --git a/mm/rmap.c b/mm/rmap.c index 171b68768df1..326d5d89e45c 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -62,6 +62,8 @@ #include +#include + #include "internal.h" static struct kmem_cache *anon_vma_cachep; @@ -583,6 +585,89 @@ vma_address(struct page *page, struct vm_area_struct *vma) return address; } +#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH +static void percpu_flush_tlb_batch_pages(void *data) +{ + /* + * All TLB entries are flushed on the assumption that it is + * cheaper to flush all TLBs and let them be refilled than + * flushing individual PFNs. Note that we do not track mm's + * to flush as that might simply be multiple full TLB flushes + * for no gain. + */ + count_vm_tlb_event(NR_TLB_REMOTE_FLUSH_RECEIVED); + flush_tlb_local(); +} + +/* + * Flush TLB entries for recently unmapped pages from remote CPUs. It is + * important if a PTE was dirty when it was unmapped that it's flushed + * before any IO is initiated on the page to prevent lost writes. Similarly, + * it must be flushed before freeing to prevent data leakage. + */ +void try_to_unmap_flush(void) +{ + struct tlbflush_unmap_batch *tlb_ubc = ¤t->tlb_ubc; + int cpu; + + if (!tlb_ubc->flush_required) + return; + + cpu = get_cpu(); + + trace_tlb_flush(TLB_REMOTE_SHOOTDOWN, -1UL); + + if (cpumask_test_cpu(cpu, &tlb_ubc->cpumask)) + percpu_flush_tlb_batch_pages(&tlb_ubc->cpumask); + + if (cpumask_any_but(&tlb_ubc->cpumask, cpu) < nr_cpu_ids) { + smp_call_function_many(&tlb_ubc->cpumask, + percpu_flush_tlb_batch_pages, (void *)tlb_ubc, true); + } + cpumask_clear(&tlb_ubc->cpumask); + tlb_ubc->flush_required = false; + put_cpu(); +} + +static void set_tlb_ubc_flush_pending(struct mm_struct *mm, + struct page *page) +{ + struct tlbflush_unmap_batch *tlb_ubc = ¤t->tlb_ubc; + + cpumask_or(&tlb_ubc->cpumask, &tlb_ubc->cpumask, mm_cpumask(mm)); + tlb_ubc->flush_required = true; +} + +/* + * Returns true if the TLB flush should be deferred to the end of a batch of + * unmap operations to reduce IPIs. + */ +static bool should_defer_flush(struct mm_struct *mm, enum ttu_flags flags) +{ + bool should_defer = false; + + if (!(flags & TTU_BATCH_FLUSH)) + return false; + + /* If remote CPUs need to be flushed then defer batch the flush */ + if (cpumask_any_but(mm_cpumask(mm), get_cpu()) < nr_cpu_ids) + should_defer = true; + put_cpu(); + + return should_defer; +} +#else +static void set_tlb_ubc_flush_pending(struct mm_struct *mm, + struct page *page) +{ +} + +static bool should_defer_flush(struct mm_struct *mm, enum ttu_flags flags) +{ + return false; +} +#endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */ + /* * At what user virtual address is page expected in vma? * Caller should check the page is actually part of the vma. @@ -1220,7 +1305,24 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, /* Nuke the page table entry. */ flush_cache_page(vma, address, page_to_pfn(page)); - pteval = ptep_clear_flush(vma, address, pte); + if (should_defer_flush(mm, flags)) { + /* + * We clear the PTE but do not flush so potentially a remote + * CPU could still be writing to the page. If the entry was + * previously clean then the architecture must guarantee that + * a clear->dirty transition on a cached TLB entry is written + * through and traps if the PTE is unmapped. + */ + pteval = ptep_get_and_clear(mm, address, pte); + + /* Potentially writable TLBs must be flushed before IO */ + if (pte_dirty(pteval)) + flush_tlb_page(vma, address); + else + set_tlb_ubc_flush_pending(mm, page); + } else { + pteval = ptep_clear_flush(vma, address, pte); + } /* Move the dirty bit to the physical page now the pte is gone. */ if (pte_dirty(pteval)) diff --git a/mm/vmscan.c b/mm/vmscan.c index 8286938c70de..99ec00d6a5dd 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1057,7 +1057,8 @@ static unsigned long shrink_page_list(struct list_head *page_list, * processes. Try to unmap it here. */ if (page_mapped(page) && mapping) { - switch (try_to_unmap(page, ttu_flags)) { + switch (try_to_unmap(page, + ttu_flags|TTU_BATCH_FLUSH)) { case SWAP_FAIL: goto activate_locked; case SWAP_AGAIN: @@ -1208,6 +1209,7 @@ keep: } mem_cgroup_uncharge_list(&free_pages); + try_to_unmap_flush(); free_hot_cold_page_list(&free_pages, true); list_splice(&ret_pages, page_list); @@ -2151,6 +2153,23 @@ out: } } +#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH +static void init_tlb_ubc(void) +{ + /* + * This deliberately does not clear the cpumask as it's expensive + * and unnecessary. If there happens to be data in there then the + * first SWAP_CLUSTER_MAX pages will send an unnecessary IPI and + * then will be cleared. + */ + current->tlb_ubc.flush_required = false; +} +#else +static inline void init_tlb_ubc(void) +{ +} +#endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */ + /* * This is a basic per-zone page freer. Used by both kswapd and direct reclaim. */ @@ -2185,6 +2204,8 @@ static void shrink_lruvec(struct lruvec *lruvec, int swappiness, scan_adjusted = (global_reclaim(sc) && !current_is_kswapd() && sc->priority == DEF_PRIORITY); + init_tlb_ubc(); + blk_start_plug(&plug); while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] || nr[LRU_INACTIVE_FILE]) { -- cgit v1.2.3-70-g09d2 From d950c9477d51f0cefc2ed3cf76e695d46af0d9c1 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Fri, 4 Sep 2015 15:47:35 -0700 Subject: mm: defer flush of writable TLB entries If a PTE is unmapped and it's dirty then it was writable recently. Due to deferred TLB flushing, it's best to assume a writable TLB cache entry exists. With that assumption, the TLB must be flushed before any IO can start or the page is freed to avoid lost writes or data corruption. This patch defers flushing of potentially writable TLBs as long as possible. Signed-off-by: Mel Gorman Reviewed-by: Rik van Riel Cc: Dave Hansen Acked-by: Ingo Molnar Cc: Linus Torvalds Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/sched.h | 7 +++++++ mm/internal.h | 4 ++++ mm/rmap.c | 28 +++++++++++++++++++++------- mm/vmscan.c | 7 ++++++- 4 files changed, 38 insertions(+), 8 deletions(-) (limited to 'mm/vmscan.c') diff --git a/include/linux/sched.h b/include/linux/sched.h index 3c602c20c717..a4ab9daa387c 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1354,6 +1354,13 @@ struct tlbflush_unmap_batch { /* True if any bit in cpumask is set */ bool flush_required; + + /* + * If true then the PTE was dirty when unmapped. The entry must be + * flushed before IO is initiated or a stale TLB entry potentially + * allows an update without redirtying the page. + */ + bool writable; }; struct task_struct { diff --git a/mm/internal.h b/mm/internal.h index bd6372ac5f7f..1195dd2d6a2b 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -431,10 +431,14 @@ struct tlbflush_unmap_batch; #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH void try_to_unmap_flush(void); +void try_to_unmap_flush_dirty(void); #else static inline void try_to_unmap_flush(void) { } +static inline void try_to_unmap_flush_dirty(void) +{ +} #endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */ #endif /* __MM_INTERNAL_H */ diff --git a/mm/rmap.c b/mm/rmap.c index 326d5d89e45c..0db38e7d0a72 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -626,16 +626,34 @@ void try_to_unmap_flush(void) } cpumask_clear(&tlb_ubc->cpumask); tlb_ubc->flush_required = false; + tlb_ubc->writable = false; put_cpu(); } +/* Flush iff there are potentially writable TLB entries that can race with IO */ +void try_to_unmap_flush_dirty(void) +{ + struct tlbflush_unmap_batch *tlb_ubc = ¤t->tlb_ubc; + + if (tlb_ubc->writable) + try_to_unmap_flush(); +} + static void set_tlb_ubc_flush_pending(struct mm_struct *mm, - struct page *page) + struct page *page, bool writable) { struct tlbflush_unmap_batch *tlb_ubc = ¤t->tlb_ubc; cpumask_or(&tlb_ubc->cpumask, &tlb_ubc->cpumask, mm_cpumask(mm)); tlb_ubc->flush_required = true; + + /* + * If the PTE was dirty then it's best to assume it's writable. The + * caller must use try_to_unmap_flush_dirty() or try_to_unmap_flush() + * before the page is queued for IO. + */ + if (writable) + tlb_ubc->writable = true; } /* @@ -658,7 +676,7 @@ static bool should_defer_flush(struct mm_struct *mm, enum ttu_flags flags) } #else static void set_tlb_ubc_flush_pending(struct mm_struct *mm, - struct page *page) + struct page *page, bool writable) { } @@ -1315,11 +1333,7 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, */ pteval = ptep_get_and_clear(mm, address, pte); - /* Potentially writable TLBs must be flushed before IO */ - if (pte_dirty(pteval)) - flush_tlb_page(vma, address); - else - set_tlb_ubc_flush_pending(mm, page); + set_tlb_ubc_flush_pending(mm, page, pte_dirty(pteval)); } else { pteval = ptep_clear_flush(vma, address, pte); } diff --git a/mm/vmscan.c b/mm/vmscan.c index 99ec00d6a5dd..b1139039122a 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1098,7 +1098,12 @@ static unsigned long shrink_page_list(struct list_head *page_list, if (!sc->may_writepage) goto keep_locked; - /* Page is dirty, try to write it out here */ + /* + * Page is dirty. Flush the TLB if a writable entry + * potentially exists to avoid CPU writes after IO + * starts and then write it out here. + */ + try_to_unmap_flush_dirty(); switch (pageout(page, mapping, sc)) { case PAGE_KEEP: goto keep_locked; -- cgit v1.2.3-70-g09d2 From 33398cf2f360c5ce24c8a22436d52a06ad4e5eb5 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Tue, 8 Sep 2015 15:01:02 -0700 Subject: memcg: export struct mem_cgroup mem_cgroup structure is defined in mm/memcontrol.c currently which means that the code outside of this file has to use external API even for trivial access stuff. This patch exports mm_struct with its dependencies and makes some of the exported functions inlines. This even helps to reduce the code size a bit (make defconfig + CONFIG_MEMCG=y) text data bss dec hex filename 12355346 1823792 1089536 15268674 e8fb42 vmlinux.before 12354970 1823792 1089536 15268298 e8f9ca vmlinux.after This is not much (370B) but better than nothing. We also save a function call in some hot paths like callers of mem_cgroup_count_vm_event which is used for accounting. The patch doesn't introduce any functional changes. [vdavykov@parallels.com: inline memcg_kmem_is_active] [vdavykov@parallels.com: do not expose type outside of CONFIG_MEMCG] [akpm@linux-foundation.org: memcontrol.h needs eventfd.h for eventfd_ctx] [akpm@linux-foundation.org: export mem_cgroup_from_task() to modules] Signed-off-by: Michal Hocko Reviewed-by: Vladimir Davydov Suggested-by: Johannes Weiner Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 370 +++++++++++++++++++++++++++++++++++++++++---- include/linux/swap.h | 10 +- include/net/sock.h | 28 ---- mm/memcontrol.c | 315 +------------------------------------- mm/memory-failure.c | 2 +- mm/slab_common.c | 2 +- mm/vmscan.c | 2 +- 7 files changed, 351 insertions(+), 378 deletions(-) (limited to 'mm/vmscan.c') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 73b02b0a8f60..ab2f6880e27b 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -23,6 +23,11 @@ #include #include #include +#include +#include +#include +#include +#include struct mem_cgroup; struct page; @@ -67,12 +72,221 @@ enum mem_cgroup_events_index { MEMCG_NR_EVENTS, }; +/* + * Per memcg event counter is incremented at every pagein/pageout. With THP, + * it will be incremated by the number of pages. This counter is used for + * for trigger some periodic events. This is straightforward and better + * than using jiffies etc. to handle periodic memcg event. + */ +enum mem_cgroup_events_target { + MEM_CGROUP_TARGET_THRESH, + MEM_CGROUP_TARGET_SOFTLIMIT, + MEM_CGROUP_TARGET_NUMAINFO, + MEM_CGROUP_NTARGETS, +}; + +/* + * Bits in struct cg_proto.flags + */ +enum cg_proto_flags { + /* Currently active and new sockets should be assigned to cgroups */ + MEMCG_SOCK_ACTIVE, + /* It was ever activated; we must disarm static keys on destruction */ + MEMCG_SOCK_ACTIVATED, +}; + +struct cg_proto { + struct page_counter memory_allocated; /* Current allocated memory. */ + struct percpu_counter sockets_allocated; /* Current number of sockets. */ + int memory_pressure; + long sysctl_mem[3]; + unsigned long flags; + /* + * memcg field is used to find which memcg we belong directly + * Each memcg struct can hold more than one cg_proto, so container_of + * won't really cut. + * + * The elegant solution would be having an inverse function to + * proto_cgroup in struct proto, but that means polluting the structure + * for everybody, instead of just for memcg users. + */ + struct mem_cgroup *memcg; +}; + #ifdef CONFIG_MEMCG +struct mem_cgroup_stat_cpu { + long count[MEM_CGROUP_STAT_NSTATS]; + unsigned long events[MEMCG_NR_EVENTS]; + unsigned long nr_page_events; + unsigned long targets[MEM_CGROUP_NTARGETS]; +}; + +struct mem_cgroup_reclaim_iter { + struct mem_cgroup *position; + /* scan generation, increased every round-trip */ + unsigned int generation; +}; + +/* + * per-zone information in memory controller. + */ +struct mem_cgroup_per_zone { + struct lruvec lruvec; + unsigned long lru_size[NR_LRU_LISTS]; + + struct mem_cgroup_reclaim_iter iter[DEF_PRIORITY + 1]; + + struct rb_node tree_node; /* RB tree node */ + unsigned long usage_in_excess;/* Set to the value by which */ + /* the soft limit is exceeded*/ + bool on_tree; + struct mem_cgroup *memcg; /* Back pointer, we cannot */ + /* use container_of */ +}; + +struct mem_cgroup_per_node { + struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; +}; + +struct mem_cgroup_threshold { + struct eventfd_ctx *eventfd; + unsigned long threshold; +}; + +/* For threshold */ +struct mem_cgroup_threshold_ary { + /* An array index points to threshold just below or equal to usage. */ + int current_threshold; + /* Size of entries[] */ + unsigned int size; + /* Array of thresholds */ + struct mem_cgroup_threshold entries[0]; +}; + +struct mem_cgroup_thresholds { + /* Primary thresholds array */ + struct mem_cgroup_threshold_ary *primary; + /* + * Spare threshold array. + * This is needed to make mem_cgroup_unregister_event() "never fail". + * It must be able to store at least primary->size - 1 entries. + */ + struct mem_cgroup_threshold_ary *spare; +}; + +/* + * The memory controller data structure. The memory controller controls both + * page cache and RSS per cgroup. We would eventually like to provide + * statistics based on the statistics developed by Rik Van Riel for clock-pro, + * to help the administrator determine what knobs to tune. + */ +struct mem_cgroup { + struct cgroup_subsys_state css; + + /* Accounted resources */ + struct page_counter memory; + struct page_counter memsw; + struct page_counter kmem; + + /* Normal memory consumption range */ + unsigned long low; + unsigned long high; + + unsigned long soft_limit; + + /* vmpressure notifications */ + struct vmpressure vmpressure; + + /* css_online() has been completed */ + int initialized; + + /* + * Should the accounting and control be hierarchical, per subtree? + */ + bool use_hierarchy; + + /* protected by memcg_oom_lock */ + bool oom_lock; + int under_oom; + + int swappiness; + /* OOM-Killer disable */ + int oom_kill_disable; + + /* protect arrays of thresholds */ + struct mutex thresholds_lock; + + /* thresholds for memory usage. RCU-protected */ + struct mem_cgroup_thresholds thresholds; + + /* thresholds for mem+swap usage. RCU-protected */ + struct mem_cgroup_thresholds memsw_thresholds; + + /* For oom notifier event fd */ + struct list_head oom_notify; + + /* + * Should we move charges of a task when a task is moved into this + * mem_cgroup ? And what type of charges should we move ? + */ + unsigned long move_charge_at_immigrate; + /* + * set > 0 if pages under this cgroup are moving to other cgroup. + */ + atomic_t moving_account; + /* taken only while moving_account > 0 */ + spinlock_t move_lock; + struct task_struct *move_lock_task; + unsigned long move_lock_flags; + /* + * percpu counter. + */ + struct mem_cgroup_stat_cpu __percpu *stat; + spinlock_t pcp_counter_lock; + +#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET) + struct cg_proto tcp_mem; +#endif +#if defined(CONFIG_MEMCG_KMEM) + /* Index in the kmem_cache->memcg_params.memcg_caches array */ + int kmemcg_id; + bool kmem_acct_activated; + bool kmem_acct_active; +#endif + + int last_scanned_node; +#if MAX_NUMNODES > 1 + nodemask_t scan_nodes; + atomic_t numainfo_events; + atomic_t numainfo_updating; +#endif + +#ifdef CONFIG_CGROUP_WRITEBACK + struct list_head cgwb_list; + struct wb_domain cgwb_domain; +#endif + + /* List of events which userspace want to receive */ + struct list_head event_list; + spinlock_t event_list_lock; + + struct mem_cgroup_per_node *nodeinfo[0]; + /* WARNING: nodeinfo must be the last member here */ +}; extern struct cgroup_subsys_state *mem_cgroup_root_css; -void mem_cgroup_events(struct mem_cgroup *memcg, +/** + * mem_cgroup_events - count memory events against a cgroup + * @memcg: the memory cgroup + * @idx: the event index + * @nr: the number of events to account for + */ +static inline void mem_cgroup_events(struct mem_cgroup *memcg, enum mem_cgroup_events_index idx, - unsigned int nr); + unsigned int nr) +{ + this_cpu_add(memcg->stat->events[idx], nr); +} bool mem_cgroup_low(struct mem_cgroup *root, struct mem_cgroup *memcg); @@ -90,15 +304,31 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage, struct lruvec *mem_cgroup_zone_lruvec(struct zone *, struct mem_cgroup *); struct lruvec *mem_cgroup_page_lruvec(struct page *, struct zone *); -bool mem_cgroup_is_descendant(struct mem_cgroup *memcg, - struct mem_cgroup *root); bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg); extern struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page); extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p); extern struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg); -extern struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css); +static inline +struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css){ + return css ? container_of(css, struct mem_cgroup, css) : NULL; +} + +struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *, + struct mem_cgroup *, + struct mem_cgroup_reclaim_cookie *); +void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *); + +static inline bool mem_cgroup_is_descendant(struct mem_cgroup *memcg, + struct mem_cgroup *root) +{ + if (root == memcg) + return true; + if (!root->use_hierarchy) + return false; + return cgroup_is_descendant(memcg->css.cgroup, root->css.cgroup); +} static inline bool mm_match_cgroup(struct mm_struct *mm, struct mem_cgroup *memcg) @@ -114,22 +344,65 @@ static inline bool mm_match_cgroup(struct mm_struct *mm, return match; } -extern struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg); extern struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page); -struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *, - struct mem_cgroup *, - struct mem_cgroup_reclaim_cookie *); -void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *); +static inline bool mem_cgroup_disabled(void) +{ + if (memory_cgrp_subsys.disabled) + return true; + return false; +} /* * For memory reclaim. */ -int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec); -bool mem_cgroup_lruvec_online(struct lruvec *lruvec); int mem_cgroup_select_victim_node(struct mem_cgroup *memcg); -unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list); -void mem_cgroup_update_lru_size(struct lruvec *, enum lru_list, int); + +void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru, + int nr_pages); + +static inline bool mem_cgroup_lruvec_online(struct lruvec *lruvec) +{ + struct mem_cgroup_per_zone *mz; + struct mem_cgroup *memcg; + + if (mem_cgroup_disabled()) + return true; + + mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec); + memcg = mz->memcg; + + return !!(memcg->css.flags & CSS_ONLINE); +} + +static inline +unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru) +{ + struct mem_cgroup_per_zone *mz; + + mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec); + return mz->lru_size[lru]; +} + +static inline int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec) +{ + unsigned long inactive_ratio; + unsigned long inactive; + unsigned long active; + unsigned long gb; + + inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON); + active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON); + + gb = (inactive + active) >> (30 - PAGE_SHIFT); + if (gb) + inactive_ratio = int_sqrt(10 * gb); + else + inactive_ratio = 1; + + return inactive * inactive_ratio < active; +} + extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p); @@ -156,18 +429,26 @@ bool mem_cgroup_oom_synchronize(bool wait); extern int do_swap_account; #endif -static inline bool mem_cgroup_disabled(void) -{ - if (memory_cgrp_subsys.disabled) - return true; - return false; -} - struct mem_cgroup *mem_cgroup_begin_page_stat(struct page *page); -void mem_cgroup_update_page_stat(struct mem_cgroup *memcg, - enum mem_cgroup_stat_index idx, int val); void mem_cgroup_end_page_stat(struct mem_cgroup *memcg); +/** + * mem_cgroup_update_page_stat - update page state statistics + * @memcg: memcg to account against + * @idx: page state item to account + * @val: number of pages (positive or negative) + * + * See mem_cgroup_begin_page_stat() for locking requirements. + */ +static inline void mem_cgroup_update_page_stat(struct mem_cgroup *memcg, + enum mem_cgroup_stat_index idx, int val) +{ + VM_BUG_ON(!rcu_read_lock_held()); + + if (memcg) + this_cpu_add(memcg->stat->count[idx], val); +} + static inline void mem_cgroup_inc_page_stat(struct mem_cgroup *memcg, enum mem_cgroup_stat_index idx) { @@ -184,13 +465,31 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, gfp_t gfp_mask, unsigned long *total_scanned); -void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx); static inline void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx) { + struct mem_cgroup *memcg; + if (mem_cgroup_disabled()) return; - __mem_cgroup_count_vm_event(mm, idx); + + rcu_read_lock(); + memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); + if (unlikely(!memcg)) + goto out; + + switch (idx) { + case PGFAULT: + this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]); + break; + case PGMAJFAULT: + this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]); + break; + default: + BUG(); + } +out: + rcu_read_unlock(); } #ifdef CONFIG_TRANSPARENT_HUGEPAGE void mem_cgroup_split_huge_fixup(struct page *head); @@ -275,12 +574,6 @@ static inline bool task_in_mem_cgroup(struct task_struct *task, return true; } -static inline struct cgroup_subsys_state - *mem_cgroup_css(struct mem_cgroup *memcg) -{ - return NULL; -} - static inline struct mem_cgroup * mem_cgroup_iter(struct mem_cgroup *root, struct mem_cgroup *prev, @@ -444,7 +737,10 @@ static inline bool memcg_kmem_enabled(void) return static_key_false(&memcg_kmem_enabled_key); } -bool memcg_kmem_is_active(struct mem_cgroup *memcg); +static inline bool memcg_kmem_is_active(struct mem_cgroup *memcg) +{ + return memcg->kmem_acct_active; +} /* * In general, we'll do everything in our power to not incur in any overhead @@ -463,7 +759,15 @@ void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, int order); void __memcg_kmem_uncharge_pages(struct page *page, int order); -int memcg_cache_id(struct mem_cgroup *memcg); +/* + * helper for acessing a memcg's index. It will be used as an index in the + * child cache array in kmem_cache, and also to derive its name. This function + * will return -1 when this is not a kmem-limited memcg. + */ +static inline int memcg_cache_id(struct mem_cgroup *memcg) +{ + return memcg ? memcg->kmemcg_id : -1; +} struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep); void __memcg_kmem_put_cache(struct kmem_cache *cachep); diff --git a/include/linux/swap.h b/include/linux/swap.h index 6282f1eb3d6a..2ce190709280 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -351,7 +351,15 @@ extern void check_move_unevictable_pages(struct page **, int nr_pages); extern int kswapd_run(int nid); extern void kswapd_stop(int nid); #ifdef CONFIG_MEMCG -extern int mem_cgroup_swappiness(struct mem_cgroup *mem); +static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg) +{ + /* root ? */ + if (mem_cgroup_disabled() || !memcg->css.parent) + return vm_swappiness; + + return memcg->swappiness; +} + #else static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) { diff --git a/include/net/sock.h b/include/net/sock.h index 43c6abcf06ab..a98c71ea40c5 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1042,34 +1042,6 @@ struct proto { #endif }; -/* - * Bits in struct cg_proto.flags - */ -enum cg_proto_flags { - /* Currently active and new sockets should be assigned to cgroups */ - MEMCG_SOCK_ACTIVE, - /* It was ever activated; we must disarm static keys on destruction */ - MEMCG_SOCK_ACTIVATED, -}; - -struct cg_proto { - struct page_counter memory_allocated; /* Current allocated memory. */ - struct percpu_counter sockets_allocated; /* Current number of sockets. */ - int memory_pressure; - long sysctl_mem[3]; - unsigned long flags; - /* - * memcg field is used to find which memcg we belong directly - * Each memcg struct can hold more than one cg_proto, so container_of - * won't really cut. - * - * The elegant solution would be having an inverse function to - * proto_cgroup in struct proto, but that means polluting the structure - * for everybody, instead of just for memcg users. - */ - struct mem_cgroup *memcg; -}; - int proto_register(struct proto *prot, int alloc_slab); void proto_unregister(struct proto *prot); diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 9871f13fc35b..6935f77589e7 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -111,56 +111,10 @@ static const char * const mem_cgroup_lru_names[] = { "unevictable", }; -/* - * Per memcg event counter is incremented at every pagein/pageout. With THP, - * it will be incremated by the number of pages. This counter is used for - * for trigger some periodic events. This is straightforward and better - * than using jiffies etc. to handle periodic memcg event. - */ -enum mem_cgroup_events_target { - MEM_CGROUP_TARGET_THRESH, - MEM_CGROUP_TARGET_SOFTLIMIT, - MEM_CGROUP_TARGET_NUMAINFO, - MEM_CGROUP_NTARGETS, -}; #define THRESHOLDS_EVENTS_TARGET 128 #define SOFTLIMIT_EVENTS_TARGET 1024 #define NUMAINFO_EVENTS_TARGET 1024 -struct mem_cgroup_stat_cpu { - long count[MEM_CGROUP_STAT_NSTATS]; - unsigned long events[MEMCG_NR_EVENTS]; - unsigned long nr_page_events; - unsigned long targets[MEM_CGROUP_NTARGETS]; -}; - -struct reclaim_iter { - struct mem_cgroup *position; - /* scan generation, increased every round-trip */ - unsigned int generation; -}; - -/* - * per-zone information in memory controller. - */ -struct mem_cgroup_per_zone { - struct lruvec lruvec; - unsigned long lru_size[NR_LRU_LISTS]; - - struct reclaim_iter iter[DEF_PRIORITY + 1]; - - struct rb_node tree_node; /* RB tree node */ - unsigned long usage_in_excess;/* Set to the value by which */ - /* the soft limit is exceeded*/ - bool on_tree; - struct mem_cgroup *memcg; /* Back pointer, we cannot */ - /* use container_of */ -}; - -struct mem_cgroup_per_node { - struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; -}; - /* * Cgroups above their limits are maintained in a RB-Tree, independent of * their hierarchy representation @@ -181,32 +135,6 @@ struct mem_cgroup_tree { static struct mem_cgroup_tree soft_limit_tree __read_mostly; -struct mem_cgroup_threshold { - struct eventfd_ctx *eventfd; - unsigned long threshold; -}; - -/* For threshold */ -struct mem_cgroup_threshold_ary { - /* An array index points to threshold just below or equal to usage. */ - int current_threshold; - /* Size of entries[] */ - unsigned int size; - /* Array of thresholds */ - struct mem_cgroup_threshold entries[0]; -}; - -struct mem_cgroup_thresholds { - /* Primary thresholds array */ - struct mem_cgroup_threshold_ary *primary; - /* - * Spare threshold array. - * This is needed to make mem_cgroup_unregister_event() "never fail". - * It must be able to store at least primary->size - 1 entries. - */ - struct mem_cgroup_threshold_ary *spare; -}; - /* for OOM */ struct mem_cgroup_eventfd_list { struct list_head list; @@ -256,113 +184,6 @@ struct mem_cgroup_event { static void mem_cgroup_threshold(struct mem_cgroup *memcg); static void mem_cgroup_oom_notify(struct mem_cgroup *memcg); -/* - * The memory controller data structure. The memory controller controls both - * page cache and RSS per cgroup. We would eventually like to provide - * statistics based on the statistics developed by Rik Van Riel for clock-pro, - * to help the administrator determine what knobs to tune. - */ -struct mem_cgroup { - struct cgroup_subsys_state css; - - /* Accounted resources */ - struct page_counter memory; - struct page_counter memsw; - struct page_counter kmem; - - /* Normal memory consumption range */ - unsigned long low; - unsigned long high; - - unsigned long soft_limit; - - /* vmpressure notifications */ - struct vmpressure vmpressure; - - /* css_online() has been completed */ - int initialized; - - /* - * Should the accounting and control be hierarchical, per subtree? - */ - bool use_hierarchy; - - /* protected by memcg_oom_lock */ - bool oom_lock; - int under_oom; - - int swappiness; - /* OOM-Killer disable */ - int oom_kill_disable; - - /* protect arrays of thresholds */ - struct mutex thresholds_lock; - - /* thresholds for memory usage. RCU-protected */ - struct mem_cgroup_thresholds thresholds; - - /* thresholds for mem+swap usage. RCU-protected */ - struct mem_cgroup_thresholds memsw_thresholds; - - /* For oom notifier event fd */ - struct list_head oom_notify; - - /* - * Should we move charges of a task when a task is moved into this - * mem_cgroup ? And what type of charges should we move ? - */ - unsigned long move_charge_at_immigrate; - /* - * set > 0 if pages under this cgroup are moving to other cgroup. - */ - atomic_t moving_account; - /* taken only while moving_account > 0 */ - spinlock_t move_lock; - struct task_struct *move_lock_task; - unsigned long move_lock_flags; - /* - * percpu counter. - */ - struct mem_cgroup_stat_cpu __percpu *stat; - spinlock_t pcp_counter_lock; - -#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET) - struct cg_proto tcp_mem; -#endif -#if defined(CONFIG_MEMCG_KMEM) - /* Index in the kmem_cache->memcg_params.memcg_caches array */ - int kmemcg_id; - bool kmem_acct_activated; - bool kmem_acct_active; -#endif - - int last_scanned_node; -#if MAX_NUMNODES > 1 - nodemask_t scan_nodes; - atomic_t numainfo_events; - atomic_t numainfo_updating; -#endif - -#ifdef CONFIG_CGROUP_WRITEBACK - struct list_head cgwb_list; - struct wb_domain cgwb_domain; -#endif - - /* List of events which userspace want to receive */ - struct list_head event_list; - spinlock_t event_list_lock; - - struct mem_cgroup_per_node *nodeinfo[0]; - /* WARNING: nodeinfo must be the last member here */ -}; - -#ifdef CONFIG_MEMCG_KMEM -bool memcg_kmem_is_active(struct mem_cgroup *memcg) -{ - return memcg->kmem_acct_active; -} -#endif - /* Stuffs for move charges at task migration. */ /* * Types of charges to be moved. @@ -423,11 +244,6 @@ enum res_type { */ static DEFINE_MUTEX(memcg_create_mutex); -struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s) -{ - return s ? container_of(s, struct mem_cgroup, css) : NULL; -} - /* Some nice accessors for the vmpressure. */ struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg) { @@ -593,11 +409,6 @@ mem_cgroup_zone_zoneinfo(struct mem_cgroup *memcg, struct zone *zone) return &memcg->nodeinfo[nid]->zoneinfo[zid]; } -struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg) -{ - return &memcg->css; -} - /** * mem_cgroup_css_from_page - css of the memcg associated with a page * @page: page of interest @@ -876,14 +687,6 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, __this_cpu_add(memcg->stat->nr_page_events, nr_pages); } -unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru) -{ - struct mem_cgroup_per_zone *mz; - - mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec); - return mz->lru_size[lru]; -} - static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg, int nid, unsigned int lru_mask) @@ -986,6 +789,7 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) return mem_cgroup_from_css(task_css(p, memory_cgrp_id)); } +EXPORT_SYMBOL(mem_cgroup_from_task); static struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) { @@ -1031,7 +835,7 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, struct mem_cgroup *prev, struct mem_cgroup_reclaim_cookie *reclaim) { - struct reclaim_iter *uninitialized_var(iter); + struct mem_cgroup_reclaim_iter *uninitialized_var(iter); struct cgroup_subsys_state *css = NULL; struct mem_cgroup *memcg = NULL; struct mem_cgroup *pos = NULL; @@ -1173,30 +977,6 @@ void mem_cgroup_iter_break(struct mem_cgroup *root, iter != NULL; \ iter = mem_cgroup_iter(NULL, iter, NULL)) -void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx) -{ - struct mem_cgroup *memcg; - - rcu_read_lock(); - memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); - if (unlikely(!memcg)) - goto out; - - switch (idx) { - case PGFAULT: - this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]); - break; - case PGMAJFAULT: - this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]); - break; - default: - BUG(); - } -out: - rcu_read_unlock(); -} -EXPORT_SYMBOL(__mem_cgroup_count_vm_event); - /** * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg * @zone: zone of the wanted lruvec @@ -1295,15 +1075,6 @@ void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru, VM_BUG_ON((long)(*lru_size) < 0); } -bool mem_cgroup_is_descendant(struct mem_cgroup *memcg, struct mem_cgroup *root) -{ - if (root == memcg) - return true; - if (!root->use_hierarchy) - return false; - return cgroup_is_descendant(memcg->css.cgroup, root->css.cgroup); -} - bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg) { struct mem_cgroup *task_memcg; @@ -1330,39 +1101,6 @@ bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg) return ret; } -int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec) -{ - unsigned long inactive_ratio; - unsigned long inactive; - unsigned long active; - unsigned long gb; - - inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON); - active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON); - - gb = (inactive + active) >> (30 - PAGE_SHIFT); - if (gb) - inactive_ratio = int_sqrt(10 * gb); - else - inactive_ratio = 1; - - return inactive * inactive_ratio < active; -} - -bool mem_cgroup_lruvec_online(struct lruvec *lruvec) -{ - struct mem_cgroup_per_zone *mz; - struct mem_cgroup *memcg; - - if (mem_cgroup_disabled()) - return true; - - mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec); - memcg = mz->memcg; - - return !!(memcg->css.flags & CSS_ONLINE); -} - #define mem_cgroup_from_counter(counter, member) \ container_of(counter, struct mem_cgroup, member) @@ -1394,15 +1132,6 @@ static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg) return margin; } -int mem_cgroup_swappiness(struct mem_cgroup *memcg) -{ - /* root ? */ - if (mem_cgroup_disabled() || !memcg->css.parent) - return vm_swappiness; - - return memcg->swappiness; -} - /* * A routine for checking "mem" is under move_account() or not. * @@ -2067,23 +1796,6 @@ void mem_cgroup_end_page_stat(struct mem_cgroup *memcg) } EXPORT_SYMBOL(mem_cgroup_end_page_stat); -/** - * mem_cgroup_update_page_stat - update page state statistics - * @memcg: memcg to account against - * @idx: page state item to account - * @val: number of pages (positive or negative) - * - * See mem_cgroup_begin_page_stat() for locking requirements. - */ -void mem_cgroup_update_page_stat(struct mem_cgroup *memcg, - enum mem_cgroup_stat_index idx, int val) -{ - VM_BUG_ON(!rcu_read_lock_held()); - - if (memcg) - this_cpu_add(memcg->stat->count[idx], val); -} - /* * size of first charge trial. "32" comes from vmscan.c's magic value. * TODO: maybe necessary to use big numbers in big irons. @@ -2509,16 +2221,6 @@ void memcg_uncharge_kmem(struct mem_cgroup *memcg, unsigned long nr_pages) css_put_many(&memcg->css, nr_pages); } -/* - * helper for acessing a memcg's index. It will be used as an index in the - * child cache array in kmem_cache, and also to derive its name. This function - * will return -1 when this is not a kmem-limited memcg. - */ -int memcg_cache_id(struct mem_cgroup *memcg) -{ - return memcg ? memcg->kmemcg_id : -1; -} - static int memcg_alloc_cache_id(void) { int id, size; @@ -5525,19 +5227,6 @@ struct cgroup_subsys memory_cgrp_subsys = { .early_init = 0, }; -/** - * mem_cgroup_events - count memory events against a cgroup - * @memcg: the memory cgroup - * @idx: the event index - * @nr: the number of events to account for - */ -void mem_cgroup_events(struct mem_cgroup *memcg, - enum mem_cgroup_events_index idx, - unsigned int nr) -{ - this_cpu_add(memcg->stat->events[idx], nr); -} - /** * mem_cgroup_low - check if memory consumption is below the normal range * @root: the highest ancestor to consider diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 1f4446a90cef..016c814101ed 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -146,7 +146,7 @@ static int hwpoison_filter_task(struct page *p) if (!mem) return -EINVAL; - css = mem_cgroup_css(mem); + css = &mem->css; ino = cgroup_ino(css->cgroup); css_put(css); diff --git a/mm/slab_common.c b/mm/slab_common.c index bde04a699ab6..5ce4faeb16fb 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -500,7 +500,7 @@ void memcg_create_kmem_cache(struct mem_cgroup *memcg, struct kmem_cache *root_cache) { static char memcg_name_buf[NAME_MAX + 1]; /* protected by slab_mutex */ - struct cgroup_subsys_state *css = mem_cgroup_css(memcg); + struct cgroup_subsys_state *css = &memcg->css; struct memcg_cache_array *arr; struct kmem_cache *s = NULL; char *cache_name; diff --git a/mm/vmscan.c b/mm/vmscan.c index b1139039122a..bf23c88621ce 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -175,7 +175,7 @@ static bool sane_reclaim(struct scan_control *sc) if (!memcg) return true; #ifdef CONFIG_CGROUP_WRITEBACK - if (cgroup_on_dfl(mem_cgroup_css(memcg)->cgroup)) + if (memcg->css.cgroup) return true; #endif return false; -- cgit v1.2.3-70-g09d2 From 0b802f101d0c6caeeee89066dc2c8665082a83df Mon Sep 17 00:00:00 2001 From: Vladimir Davydov Date: Tue, 8 Sep 2015 15:02:18 -0700 Subject: mm: vmscan: never isolate more pages than necessary If transparent huge pages are enabled, we can isolate many more pages than we actually need to scan, because we count both single and huge pages equally in isolate_lru_pages(). Since commit 5bc7b8aca942d ("mm: thp: add split tail pages to shrink page list in page reclaim"), we scan all the tail pages immediately after a huge page split (see shrink_page_list()). As a result, we can reclaim up to SWAP_CLUSTER_MAX * HPAGE_PMD_NR (512 MB) in one run! This is easy to catch on memcg reclaim with zswap enabled. The latter makes swapout instant so that if we happen to scan an unreferenced huge page we will evict both its head and tail pages immediately, which is likely to result in excessive reclaim. Signed-off-by: Vladimir Davydov Cc: Johannes Weiner Reviewed-by: Michal Hocko Cc: Vlastimil Babka Cc: Minchan Kim Cc: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'mm/vmscan.c') diff --git a/mm/vmscan.c b/mm/vmscan.c index bf23c88621ce..0b1aab411cb0 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1359,7 +1359,8 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, unsigned long nr_taken = 0; unsigned long scan; - for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) { + for (scan = 0; scan < nr_to_scan && nr_taken < nr_to_scan && + !list_empty(src); scan++) { struct page *page; int nr_pages; -- cgit v1.2.3-70-g09d2 From c54839a722a02818677bcabe57e957f0ce4f841d Mon Sep 17 00:00:00 2001 From: Jaewon Kim Date: Tue, 8 Sep 2015 15:02:21 -0700 Subject: vmscan: fix increasing nr_isolated incurred by putback unevictable pages reclaim_clean_pages_from_list() assumes that shrink_page_list() returns number of pages removed from the candidate list. But shrink_page_list() puts back mlocked pages without passing it to caller and without counting as nr_reclaimed. This increases nr_isolated. To fix this, this patch changes shrink_page_list() to pass unevictable pages back to caller. Caller will take care those pages. Minchan said: It fixes two issues. 1. With unevictable page, cma_alloc will be successful. Exactly speaking, cma_alloc of current kernel will fail due to unevictable pages. 2. fix leaking of NR_ISOLATED counter of vmstat With it, too_many_isolated works. Otherwise, it could make hang until the process get SIGKILL. Signed-off-by: Jaewon Kim Acked-by: Minchan Kim Cc: Mel Gorman Acked-by: Vlastimil Babka Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/vmscan.c') diff --git a/mm/vmscan.c b/mm/vmscan.c index 0b1aab411cb0..8276a3a615ca 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1196,7 +1196,7 @@ cull_mlocked: if (PageSwapCache(page)) try_to_free_swap(page); unlock_page(page); - putback_lru_page(page); + list_add(&page->lru, &ret_pages); continue; activate_locked: -- cgit v1.2.3-70-g09d2 From 7fadc820222497eac234d1d51a66517c00a6ca4c Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Tue, 8 Sep 2015 15:03:46 -0700 Subject: mm, vmscan: unlock page while waiting on writeback This is merely a politeness: I've not found that shrink_page_list() leads to deadlock with the page it holds locked across wait_on_page_writeback(); but nevertheless, why hold others off by keeping the page locked there? And while we're at it: remove the mistaken "not " from the commentary on this Case 3 (and a distracting blank line from Case 2, if I may). Signed-off-by: Hugh Dickins Acked-by: Michal Hocko Acked-by: Johannes Weiner Cc: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'mm/vmscan.c') diff --git a/mm/vmscan.c b/mm/vmscan.c index 8276a3a615ca..2d978b28a410 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -985,7 +985,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, * __GFP_IO|__GFP_FS for this reason); but more thought * would probably show more reasons. * - * 3) Legacy memcg encounters a page that is not already marked + * 3) Legacy memcg encounters a page that is already marked * PageReclaim. memcg does not have any dirty pages * throttling so we could easily OOM just because too many * pages are in writeback and there is nothing else to @@ -1015,12 +1015,15 @@ static unsigned long shrink_page_list(struct list_head *page_list, */ SetPageReclaim(page); nr_writeback++; - goto keep_locked; /* Case 3 above */ } else { + unlock_page(page); wait_on_page_writeback(page); + /* then go back and try same page again */ + list_add_tail(&page->lru, page_list); + continue; } } -- cgit v1.2.3-70-g09d2