diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/Kconfig.debug | 9 | ||||
| -rw-r--r-- | mm/filemap.c | 29 | ||||
| -rw-r--r-- | mm/gup.c | 4 | ||||
| -rw-r--r-- | mm/ksm.c | 2 | ||||
| -rw-r--r-- | mm/memcontrol.c | 21 | ||||
| -rw-r--r-- | mm/memory.c | 45 | ||||
| -rw-r--r-- | mm/mmap.c | 13 | ||||
| -rw-r--r-- | mm/page-writeback.c | 43 | ||||
| -rw-r--r-- | mm/page_alloc.c | 82 | ||||
| -rw-r--r-- | mm/rmap.c | 42 | ||||
| -rw-r--r-- | mm/vmscan.c | 26 |
11 files changed, 158 insertions, 158 deletions
diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug index 56badfc4810a..957d3da53ddd 100644 --- a/mm/Kconfig.debug +++ b/mm/Kconfig.debug @@ -14,7 +14,6 @@ config DEBUG_PAGEALLOC depends on !KMEMCHECK select PAGE_EXTENSION select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC - select PAGE_GUARD if ARCH_SUPPORTS_DEBUG_PAGEALLOC ---help--- Unmap pages from the kernel linear mapping after free_pages(). This results in a large slowdown, but helps to find certain types @@ -27,13 +26,5 @@ config DEBUG_PAGEALLOC that would result in incorrect warnings of memory corruption after a resume because free pages are not saved to the suspend image. -config WANT_PAGE_DEBUG_FLAGS - bool - config PAGE_POISONING bool - select WANT_PAGE_DEBUG_FLAGS - -config PAGE_GUARD - bool - select WANT_PAGE_DEBUG_FLAGS diff --git a/mm/filemap.c b/mm/filemap.c index bd8543c6508f..673e4581a2e5 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1046,8 +1046,7 @@ EXPORT_SYMBOL(find_lock_entry); * @mapping: the address_space to search * @offset: the page index * @fgp_flags: PCG flags - * @cache_gfp_mask: gfp mask to use for the page cache data page allocation - * @radix_gfp_mask: gfp mask to use for radix tree node allocation + * @gfp_mask: gfp mask to use for the page cache data page allocation * * Looks up the page cache slot at @mapping & @offset. * @@ -1056,11 +1055,9 @@ EXPORT_SYMBOL(find_lock_entry); * FGP_ACCESSED: the page will be marked accessed * FGP_LOCK: Page is return locked * FGP_CREAT: If page is not present then a new page is allocated using - * @cache_gfp_mask and added to the page cache and the VM's LRU - * list. If radix tree nodes are allocated during page cache - * insertion then @radix_gfp_mask is used. The page is returned - * locked and with an increased refcount. Otherwise, %NULL is - * returned. + * @gfp_mask and added to the page cache and the VM's LRU + * list. The page is returned locked and with an increased + * refcount. Otherwise, %NULL is returned. * * If FGP_LOCK or FGP_CREAT are specified then the function may sleep even * if the GFP flags specified for FGP_CREAT are atomic. @@ -1068,7 +1065,7 @@ EXPORT_SYMBOL(find_lock_entry); * If there is a page cache page, it is returned with an increased refcount. */ struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset, - int fgp_flags, gfp_t cache_gfp_mask, gfp_t radix_gfp_mask) + int fgp_flags, gfp_t gfp_mask) { struct page *page; @@ -1105,13 +1102,11 @@ no_page: if (!page && (fgp_flags & FGP_CREAT)) { int err; if ((fgp_flags & FGP_WRITE) && mapping_cap_account_dirty(mapping)) - cache_gfp_mask |= __GFP_WRITE; - if (fgp_flags & FGP_NOFS) { - cache_gfp_mask &= ~__GFP_FS; - radix_gfp_mask &= ~__GFP_FS; - } + gfp_mask |= __GFP_WRITE; + if (fgp_flags & FGP_NOFS) + gfp_mask &= ~__GFP_FS; - page = __page_cache_alloc(cache_gfp_mask); + page = __page_cache_alloc(gfp_mask); if (!page) return NULL; @@ -1122,7 +1117,8 @@ no_page: if (fgp_flags & FGP_ACCESSED) __SetPageReferenced(page); - err = add_to_page_cache_lru(page, mapping, offset, radix_gfp_mask); + err = add_to_page_cache_lru(page, mapping, offset, + gfp_mask & GFP_RECLAIM_MASK); if (unlikely(err)) { page_cache_release(page); page = NULL; @@ -2443,8 +2439,7 @@ struct page *grab_cache_page_write_begin(struct address_space *mapping, fgp_flags |= FGP_NOFS; page = pagecache_get_page(mapping, index, fgp_flags, - mapping_gfp_mask(mapping), - GFP_KERNEL); + mapping_gfp_mask(mapping)); if (page) wait_for_stable_page(page); @@ -296,7 +296,7 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma, return -ENOMEM; if (ret & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE)) return *flags & FOLL_HWPOISON ? -EHWPOISON : -EFAULT; - if (ret & VM_FAULT_SIGBUS) + if (ret & (VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV)) return -EFAULT; BUG(); } @@ -571,7 +571,7 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm, return -ENOMEM; if (ret & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE)) return -EHWPOISON; - if (ret & VM_FAULT_SIGBUS) + if (ret & (VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV)) return -EFAULT; BUG(); } @@ -376,7 +376,7 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr) else ret = VM_FAULT_WRITE; put_page(page); - } while (!(ret & (VM_FAULT_WRITE | VM_FAULT_SIGBUS | VM_FAULT_OOM))); + } while (!(ret & (VM_FAULT_WRITE | VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | VM_FAULT_OOM))); /* * We must loop because handle_mm_fault() may back out if there's * any difficulty e.g. if pte accessed bit gets updated concurrently. diff --git a/mm/memcontrol.c b/mm/memcontrol.c index ef91e856c7e4..683b4782019b 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1477,9 +1477,9 @@ void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) pr_info("Task in "); pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id)); - pr_info(" killed as a result of limit of "); + pr_cont(" killed as a result of limit of "); pr_cont_cgroup_path(memcg->css.cgroup); - pr_info("\n"); + pr_cont("\n"); rcu_read_unlock(); @@ -3043,18 +3043,6 @@ static int mem_cgroup_move_swap_account(swp_entry_t entry, if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { mem_cgroup_swap_statistics(from, false); mem_cgroup_swap_statistics(to, true); - /* - * This function is only called from task migration context now. - * It postpones page_counter and refcount handling till the end - * of task migration(mem_cgroup_clear_mc()) for performance - * improvement. But we cannot postpone css_get(to) because if - * the process that has been moved to @to does swap-in, the - * refcount of @to might be decreased to 0. - * - * We are in attach() phase, so the cgroup is guaranteed to be - * alive, so we can just call css_get(). - */ - css_get(&to->css); return 0; } return -EINVAL; @@ -4679,6 +4667,7 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) if (parent_css == NULL) { root_mem_cgroup = memcg; page_counter_init(&memcg->memory, NULL); + memcg->soft_limit = PAGE_COUNTER_MAX; page_counter_init(&memcg->memsw, NULL); page_counter_init(&memcg->kmem, NULL); } @@ -4724,6 +4713,7 @@ mem_cgroup_css_online(struct cgroup_subsys_state *css) if (parent->use_hierarchy) { page_counter_init(&memcg->memory, &parent->memory); + memcg->soft_limit = PAGE_COUNTER_MAX; page_counter_init(&memcg->memsw, &parent->memsw); page_counter_init(&memcg->kmem, &parent->kmem); @@ -4733,6 +4723,7 @@ mem_cgroup_css_online(struct cgroup_subsys_state *css) */ } else { page_counter_init(&memcg->memory, NULL); + memcg->soft_limit = PAGE_COUNTER_MAX; page_counter_init(&memcg->memsw, NULL); page_counter_init(&memcg->kmem, NULL); /* @@ -4807,7 +4798,7 @@ static void mem_cgroup_css_reset(struct cgroup_subsys_state *css) mem_cgroup_resize_limit(memcg, PAGE_COUNTER_MAX); mem_cgroup_resize_memsw_limit(memcg, PAGE_COUNTER_MAX); memcg_update_kmem_limit(memcg, PAGE_COUNTER_MAX); - memcg->soft_limit = 0; + memcg->soft_limit = PAGE_COUNTER_MAX; } #ifdef CONFIG_MMU diff --git a/mm/memory.c b/mm/memory.c index 649e7d440bd7..2c3536cc6c63 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -235,6 +235,9 @@ void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long static void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) { + if (!tlb->end) + return; + tlb_flush(tlb); mmu_notifier_invalidate_range(tlb->mm, tlb->start, tlb->end); #ifdef CONFIG_HAVE_RCU_TABLE_FREE @@ -247,7 +250,7 @@ static void tlb_flush_mmu_free(struct mmu_gather *tlb) { struct mmu_gather_batch *batch; - for (batch = &tlb->local; batch; batch = batch->next) { + for (batch = &tlb->local; batch && batch->nr; batch = batch->next) { free_pages_and_swap_cache(batch->pages, batch->nr); batch->nr = 0; } @@ -256,9 +259,6 @@ static void tlb_flush_mmu_free(struct mmu_gather *tlb) void tlb_flush_mmu(struct mmu_gather *tlb) { - if (!tlb->end) - return; - tlb_flush_mmu_tlbonly(tlb); tlb_flush_mmu_free(tlb); } @@ -2137,17 +2137,24 @@ reuse: if (!dirty_page) return ret; - /* - * Yes, Virginia, this is actually required to prevent a race - * with clear_page_dirty_for_io() from clearing the page dirty - * bit after it clear all dirty ptes, but before a racing - * do_wp_page installs a dirty pte. - * - * do_shared_fault is protected similarly. - */ if (!page_mkwrite) { - wait_on_page_locked(dirty_page); - set_page_dirty_balance(dirty_page); + struct address_space *mapping; + int dirtied; + + lock_page(dirty_page); + dirtied = set_page_dirty(dirty_page); + VM_BUG_ON_PAGE(PageAnon(dirty_page), dirty_page); + mapping = dirty_page->mapping; + unlock_page(dirty_page); + + if (dirtied && mapping) { + /* + * Some device drivers do not set page.mapping + * but still dirty their pages + */ + balance_dirty_pages_ratelimited(mapping); + } + /* file_update_time outside page_lock */ if (vma->vm_file) file_update_time(vma->vm_file); @@ -2378,12 +2385,12 @@ void unmap_mapping_range(struct address_space *mapping, details.last_index = ULONG_MAX; - i_mmap_lock_read(mapping); + i_mmap_lock_write(mapping); if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap))) unmap_mapping_range_tree(&mapping->i_mmap, &details); if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details); - i_mmap_unlock_read(mapping); + i_mmap_unlock_write(mapping); } EXPORT_SYMBOL(unmap_mapping_range); @@ -2593,7 +2600,7 @@ static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned lo if (prev && prev->vm_end == address) return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM; - expand_downwards(vma, address - PAGE_SIZE); + return expand_downwards(vma, address - PAGE_SIZE); } if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) { struct vm_area_struct *next = vma->vm_next; @@ -2602,7 +2609,7 @@ static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned lo if (next && next->vm_start == address + PAGE_SIZE) return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM; - expand_upwards(vma, address + PAGE_SIZE); + return expand_upwards(vma, address + PAGE_SIZE); } return 0; } @@ -2625,7 +2632,7 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, /* Check if we need to add a guard page to the stack */ if (check_stack_guard_page(vma, address) < 0) - return VM_FAULT_SIGBUS; + return VM_FAULT_SIGSEGV; /* Use the zero-page for reads */ if (!(flags & FAULT_FLAG_WRITE) && !mm_forbids_zeropage(mm)) { diff --git a/mm/mmap.c b/mm/mmap.c index 7b36aa7cc89a..7f684d5a8087 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -778,10 +778,12 @@ again: remove_next = 1 + (end > next->vm_end); if (exporter && exporter->anon_vma && !importer->anon_vma) { int error; + importer->anon_vma = exporter->anon_vma; error = anon_vma_clone(importer, exporter); - if (error) + if (error) { + importer->anon_vma = NULL; return error; - importer->anon_vma = exporter->anon_vma; + } } } @@ -2099,14 +2101,17 @@ static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, uns { struct mm_struct *mm = vma->vm_mm; struct rlimit *rlim = current->signal->rlim; - unsigned long new_start; + unsigned long new_start, actual_size; /* address space limit tests */ if (!may_expand_vm(mm, grow)) return -ENOMEM; /* Stack limit test */ - if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur)) + actual_size = size; + if (size && (vma->vm_flags & (VM_GROWSUP | VM_GROWSDOWN))) + actual_size -= PAGE_SIZE; + if (actual_size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur)) return -ENOMEM; /* mlock limit tests */ diff --git a/mm/page-writeback.c b/mm/page-writeback.c index d5d81f5384d1..6f4335238e33 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -1541,16 +1541,6 @@ pause: bdi_start_background_writeback(bdi); } -void set_page_dirty_balance(struct page *page) -{ - if (set_page_dirty(page)) { - struct address_space *mapping = page_mapping(page); - - if (mapping) - balance_dirty_pages_ratelimited(mapping); - } -} - static DEFINE_PER_CPU(int, bdp_ratelimits); /* @@ -2123,32 +2113,25 @@ EXPORT_SYMBOL(account_page_dirtied); * page dirty in that case, but not all the buffers. This is a "bottom-up" * dirtying, whereas __set_page_dirty_buffers() is a "top-down" dirtying. * - * Most callers have locked the page, which pins the address_space in memory. - * But zap_pte_range() does not lock the page, however in that case the - * mapping is pinned by the vma's ->vm_file reference. - * - * We take care to handle the case where the page was truncated from the - * mapping by re-checking page_mapping() inside tree_lock. + * The caller must ensure this doesn't race with truncation. Most will simply + * hold the page lock, but e.g. zap_pte_range() calls with the page mapped and + * the pte lock held, which also locks out truncation. */ int __set_page_dirty_nobuffers(struct page *page) { if (!TestSetPageDirty(page)) { struct address_space *mapping = page_mapping(page); - struct address_space *mapping2; unsigned long flags; if (!mapping) return 1; spin_lock_irqsave(&mapping->tree_lock, flags); - mapping2 = page_mapping(page); - if (mapping2) { /* Race with truncate? */ - BUG_ON(mapping2 != mapping); - WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(page)); - account_page_dirtied(page, mapping); - radix_tree_tag_set(&mapping->page_tree, - page_index(page), PAGECACHE_TAG_DIRTY); - } + BUG_ON(page_mapping(page) != mapping); + WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(page)); + account_page_dirtied(page, mapping); + radix_tree_tag_set(&mapping->page_tree, page_index(page), + PAGECACHE_TAG_DIRTY); spin_unlock_irqrestore(&mapping->tree_lock, flags); if (mapping->host) { /* !PageAnon && !swapper_space */ @@ -2305,12 +2288,10 @@ int clear_page_dirty_for_io(struct page *page) /* * We carefully synchronise fault handlers against * installing a dirty pte and marking the page dirty - * at this point. We do this by having them hold the - * page lock at some point after installing their - * pte, but before marking the page dirty. - * Pages are always locked coming in here, so we get - * the desired exclusion. See mm/memory.c:do_wp_page() - * for more comments. + * at this point. We do this by having them hold the + * page lock while dirtying the page, and pages are + * always locked coming in here, so we get the desired + * exclusion. */ if (TestClearPageDirty(page)) { dec_zone_page_state(page, NR_FILE_DIRTY); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 7633c503a116..8e20f9c2fa5a 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2332,12 +2332,21 @@ static inline struct page * __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order, struct zonelist *zonelist, enum zone_type high_zoneidx, nodemask_t *nodemask, struct zone *preferred_zone, - int classzone_idx, int migratetype) + int classzone_idx, int migratetype, unsigned long *did_some_progress) { struct page *page; - /* Acquire the per-zone oom lock for each zone */ + *did_some_progress = 0; + + if (oom_killer_disabled) + return NULL; + + /* + * Acquire the per-zone oom lock for each zone. If that + * fails, somebody else is making progress for us. + */ if (!oom_zonelist_trylock(zonelist, gfp_mask)) { + *did_some_progress = 1; schedule_timeout_uninterruptible(1); return NULL; } @@ -2363,12 +2372,18 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order, goto out; if (!(gfp_mask & __GFP_NOFAIL)) { + /* Coredumps can quickly deplete all memory reserves */ + if (current->flags & PF_DUMPCORE) + goto out; /* The OOM killer will not help higher order allocs */ if (order > PAGE_ALLOC_COSTLY_ORDER) goto out; /* The OOM killer does not needlessly kill tasks for lowmem */ if (high_zoneidx < ZONE_NORMAL) goto out; + /* The OOM killer does not compensate for light reclaim */ + if (!(gfp_mask & __GFP_FS)) + goto out; /* * GFP_THISNODE contains __GFP_NORETRY and we never hit this. * Sanity check for bare calls of __GFP_THISNODE, not real OOM. @@ -2381,7 +2396,7 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order, } /* Exhausted what can be done so it's blamo time */ out_of_memory(zonelist, gfp_mask, order, nodemask, false); - + *did_some_progress = 1; out: oom_zonelist_unlock(zonelist, gfp_mask); return page; @@ -2658,7 +2673,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, (gfp_mask & GFP_THISNODE) == GFP_THISNODE) goto nopage; -restart: +retry: if (!(gfp_mask & __GFP_NO_KSWAPD)) wake_all_kswapds(order, zonelist, high_zoneidx, preferred_zone, nodemask); @@ -2681,7 +2696,6 @@ restart: classzone_idx = zonelist_zone_idx(preferred_zoneref); } -rebalance: /* This is the last chance, in general, before the goto nopage. */ page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist, high_zoneidx, alloc_flags & ~ALLOC_NO_WATERMARKS, @@ -2788,54 +2802,28 @@ rebalance: if (page) goto got_pg; - /* - * If we failed to make any progress reclaiming, then we are - * running out of options and have to consider going OOM - */ - if (!did_some_progress) { - if (oom_gfp_allowed(gfp_mask)) { - if (oom_killer_disabled) - goto nopage; - /* Coredumps can quickly deplete all memory reserves */ - if ((current->flags & PF_DUMPCORE) && - !(gfp_mask & __GFP_NOFAIL)) - goto nopage; - page = __alloc_pages_may_oom(gfp_mask, order, - zonelist, high_zoneidx, - nodemask, preferred_zone, - classzone_idx, migratetype); - if (page) - goto got_pg; - - if (!(gfp_mask & __GFP_NOFAIL)) { - /* - * The oom killer is not called for high-order - * allocations that may fail, so if no progress - * is being made, there are no other options and - * retrying is unlikely to help. - */ - if (order > PAGE_ALLOC_COSTLY_ORDER) - goto nopage; - /* - * The oom killer is not called for lowmem - * allocations to prevent needlessly killing - * innocent tasks. - */ - if (high_zoneidx < ZONE_NORMAL) - goto nopage; - } - - goto restart; - } - } - /* Check if we should retry the allocation */ pages_reclaimed += did_some_progress; if (should_alloc_retry(gfp_mask, order, did_some_progress, pages_reclaimed)) { + /* + * If we fail to make progress by freeing individual + * pages, but the allocation wants us to keep going, + * start OOM killing tasks. + */ + if (!did_some_progress) { + page = __alloc_pages_may_oom(gfp_mask, order, zonelist, + high_zoneidx, nodemask, + preferred_zone, classzone_idx, + migratetype,&did_some_progress); + if (page) + goto got_pg; + if (!did_some_progress) + goto nopage; + } /* Wait for some write requests to complete then retry */ wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50); - goto rebalance; + goto retry; } else { /* * High-order allocations do not necessarily loop after diff --git a/mm/rmap.c b/mm/rmap.c index c5bc241127b2..71cd5bd0c17d 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -72,6 +72,8 @@ static inline struct anon_vma *anon_vma_alloc(void) anon_vma = kmem_cache_alloc(anon_vma_cachep, GFP_KERNEL); if (anon_vma) { atomic_set(&anon_vma->refcount, 1); + anon_vma->degree = 1; /* Reference for first vma */ + anon_vma->parent = anon_vma; /* * Initialise the anon_vma root to point to itself. If called * from fork, the root will be reset to the parents anon_vma. @@ -188,6 +190,8 @@ int anon_vma_prepare(struct vm_area_struct *vma) if (likely(!vma->anon_vma)) { vma->anon_vma = anon_vma; anon_vma_chain_link(vma, avc, anon_vma); + /* vma reference or self-parent link for new root */ + anon_vma->degree++; allocated = NULL; avc = NULL; } @@ -236,6 +240,14 @@ static inline void unlock_anon_vma_root(struct anon_vma *root) /* * Attach the anon_vmas from src to dst. * Returns 0 on success, -ENOMEM on failure. + * + * If dst->anon_vma is NULL this function tries to find and reuse existing + * anon_vma which has no vmas and only one child anon_vma. This prevents + * degradation of anon_vma hierarchy to endless linear chain in case of + * constantly forking task. On the other hand, an anon_vma with more than one + * child isn't reused even if there was no alive vma, thus rmap walker has a + * good chance of avoiding scanning the whole hierarchy when it searches where + * page is mapped. */ int anon_vma_clone(struct vm_area_struct *dst, struct vm_area_struct *src) { @@ -256,7 +268,21 @@ int anon_vma_clone(struct vm_area_struct *dst, struct vm_area_struct *src) anon_vma = pavc->anon_vma; root = lock_anon_vma_root(root, anon_vma); anon_vma_chain_link(dst, avc, anon_vma); + + /* + * Reuse existing anon_vma if its degree lower than two, + * that means it has no vma and only one anon_vma child. + * + * Do not chose parent anon_vma, otherwise first child + * will always reuse it. Root anon_vma is never reused: + * it has self-parent reference and at least one child. + */ + if (!dst->anon_vma && anon_vma != src->anon_vma && + anon_vma->degree < 2) + dst->anon_vma = anon_vma; } + if (dst->anon_vma) + dst->anon_vma->degree++; unlock_anon_vma_root(root); return 0; @@ -280,6 +306,9 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma) if (!pvma->anon_vma) return 0; + /* Drop inherited anon_vma, we'll reuse existing or allocate new. */ + vma->anon_vma = NULL; + /* * First, attach the new VMA to the parent VMA's anon_vmas, * so rmap can find non-COWed pages in child processes. @@ -288,6 +317,10 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma) if (error) return error; + /* An existing anon_vma has been reused, all done then. */ + if (vma->anon_vma) + return 0; + /* Then add our own anon_vma. */ anon_vma = anon_vma_alloc(); if (!anon_vma) @@ -301,6 +334,7 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma) * lock any of the anon_vmas in this anon_vma tree. */ anon_vma->root = pvma->anon_vma->root; + anon_vma->parent = pvma->anon_vma; /* * With refcounts, an anon_vma can stay around longer than the * process it belongs to. The root anon_vma needs to be pinned until @@ -311,6 +345,7 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma) vma->anon_vma = anon_vma; anon_vma_lock_write(anon_vma); anon_vma_chain_link(vma, avc, anon_vma); + anon_vma->parent->degree++; anon_vma_unlock_write(anon_vma); return 0; @@ -341,12 +376,16 @@ void unlink_anon_vmas(struct vm_area_struct *vma) * Leave empty anon_vmas on the list - we'll need * to free them outside the lock. */ - if (RB_EMPTY_ROOT(&anon_vma->rb_root)) + if (RB_EMPTY_ROOT(&anon_vma->rb_root)) { + anon_vma->parent->degree--; continue; + } list_del(&avc->same_vma); anon_vma_chain_free(avc); } + if (vma->anon_vma) + vma->anon_vma->degree--; unlock_anon_vma_root(root); /* @@ -357,6 +396,7 @@ void unlink_anon_vmas(struct vm_area_struct *vma) list_for_each_entry_safe(avc, next, &vma->anon_vma_chain, same_vma) { struct anon_vma *anon_vma = avc->anon_vma; + BUG_ON(anon_vma->degree); put_anon_vma(anon_vma); list_del(&avc->same_vma); diff --git a/mm/vmscan.c b/mm/vmscan.c index bd9a72bc4a1b..dcd90c891d8e 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2656,7 +2656,7 @@ static bool throttle_direct_reclaim(gfp_t gfp_mask, struct zonelist *zonelist, * should make reasonable progress. */ for_each_zone_zonelist_nodemask(zone, z, zonelist, - gfp_mask, nodemask) { + gfp_zone(gfp_mask), nodemask) { if (zone_idx(zone) > ZONE_NORMAL) continue; @@ -2921,18 +2921,20 @@ static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order, long remaining, return false; /* - * There is a potential race between when kswapd checks its watermarks - * and a process gets throttled. There is also a potential race if - * processes get throttled, kswapd wakes, a large process exits therby - * balancing the zones that causes kswapd to miss a wakeup. If kswapd - * is going to sleep, no process should be sleeping on pfmemalloc_wait - * so wake them now if necessary. If necessary, processes will wake - * kswapd and get throttled again + * The throttled processes are normally woken up in balance_pgdat() as + * soon as pfmemalloc_watermark_ok() is true. But there is a potential + * race between when kswapd checks the watermarks and a process gets + * throttled. There is also a potential race if processes get + * throttled, kswapd wakes, a large process exits thereby balancing the + * zones, which causes kswapd to exit balance_pgdat() before reaching + * the wake up checks. If kswapd is going to sleep, no process should + * be sleeping on pfmemalloc_wait, so wake them now if necessary. If + * the wake up is premature, processes will wake kswapd and get + * throttled again. The difference from wake ups in balance_pgdat() is + * that here we are under prepare_to_wait(). */ - if (waitqueue_active(&pgdat->pfmemalloc_wait)) { - wake_up(&pgdat->pfmemalloc_wait); - return false; - } + if (waitqueue_active(&pgdat->pfmemalloc_wait)) + wake_up_all(&pgdat->pfmemalloc_wait); return pgdat_balanced(pgdat, order, classzone_idx); } |