From 62695a84eb8f2e718bf4dfb21700afaa7a08e0ea Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Sat, 18 Oct 2008 20:26:09 -0700 Subject: vmscan: move isolate_lru_page() to vmscan.c On large memory systems, the VM can spend way too much time scanning through pages that it cannot (or should not) evict from memory. Not only does it use up CPU time, but it also provokes lock contention and can leave large systems under memory presure in a catatonic state. This patch series improves VM scalability by: 1) putting filesystem backed, swap backed and unevictable pages onto their own LRUs, so the system only scans the pages that it can/should evict from memory 2) switching to two handed clock replacement for the anonymous LRUs, so the number of pages that need to be scanned when the system starts swapping is bound to a reasonable number 3) keeping unevictable pages off the LRU completely, so the VM does not waste CPU time scanning them. ramfs, ramdisk, SHM_LOCKED shared memory segments and mlock()ed VMA pages are keept on the unevictable list. This patch: isolate_lru_page logically belongs to be in vmscan.c than migrate.c. It is tough, because we don't need that function without memory migration so there is a valid argument to have it in migrate.c. However a subsequent patch needs to make use of it in the core mm, so we can happily move it to vmscan.c. Also, make the function a little more generic by not requiring that it adds an isolated page to a given list. Callers can do that. Note that we now have '__isolate_lru_page()', that does something quite different, visible outside of vmscan.c for use with memory controller. Methinks we need to rationalize these names/purposes. --lts [akpm@linux-foundation.org: fix mm/memory_hotplug.c build] Signed-off-by: Nick Piggin Signed-off-by: Rik van Riel Signed-off-by: Lee Schermerhorn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/internal.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'mm/internal.h') diff --git a/mm/internal.h b/mm/internal.h index 1f43f741697..4e8e78b978b 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -39,6 +39,8 @@ static inline void __put_page(struct page *page) atomic_dec(&page->_count); } +extern int isolate_lru_page(struct page *page); + extern void __free_pages_bootmem(struct page *page, unsigned int order); /* -- cgit v1.2.3-70-g09d2 From 894bc310419ac95f4fa4142dc364401a7e607f65 Mon Sep 17 00:00:00 2001 From: Lee Schermerhorn Date: Sat, 18 Oct 2008 20:26:39 -0700 Subject: Unevictable LRU Infrastructure When the system contains lots of mlocked or otherwise unevictable pages, the pageout code (kswapd) can spend lots of time scanning over these pages. Worse still, the presence of lots of unevictable pages can confuse kswapd into thinking that more aggressive pageout modes are required, resulting in all kinds of bad behaviour. Infrastructure to manage pages excluded from reclaim--i.e., hidden from vmscan. Based on a patch by Larry Woodman of Red Hat. Reworked to maintain "unevictable" pages on a separate per-zone LRU list, to "hide" them from vmscan. Kosaki Motohiro added the support for the memory controller unevictable lru list. Pages on the unevictable list have both PG_unevictable and PG_lru set. Thus, PG_unevictable is analogous to and mutually exclusive with PG_active--it specifies which LRU list the page is on. The unevictable infrastructure is enabled by a new mm Kconfig option [CONFIG_]UNEVICTABLE_LRU. A new function 'page_evictable(page, vma)' in vmscan.c tests whether or not a page may be evictable. Subsequent patches will add the various !evictable tests. We'll want to keep these tests light-weight for use in shrink_active_list() and, possibly, the fault path. To avoid races between tasks putting pages [back] onto an LRU list and tasks that might be moving the page from non-evictable to evictable state, the new function 'putback_lru_page()' -- inverse to 'isolate_lru_page()' -- tests the "evictability" of a page after placing it on the LRU, before dropping the reference. If the page has become unevictable, putback_lru_page() will redo the 'putback', thus moving the page to the unevictable list. This way, we avoid "stranding" evictable pages on the unevictable list. [akpm@linux-foundation.org: fix fallout from out-of-order merge] [riel@redhat.com: fix UNEVICTABLE_LRU and !PROC_PAGE_MONITOR build] [nishimura@mxp.nes.nec.co.jp: remove redundant mapping check] [kosaki.motohiro@jp.fujitsu.com: unevictable-lru-infrastructure: putback_lru_page()/unevictable page handling rework] [kosaki.motohiro@jp.fujitsu.com: kill unnecessary lock_page() in vmscan.c] [kosaki.motohiro@jp.fujitsu.com: revert migration change of unevictable lru infrastructure] [kosaki.motohiro@jp.fujitsu.com: revert to unevictable-lru-infrastructure-kconfig-fix.patch] [kosaki.motohiro@jp.fujitsu.com: restore patch failure of vmstat-unevictable-and-mlocked-pages-vm-events.patch] Signed-off-by: Lee Schermerhorn Signed-off-by: Rik van Riel Signed-off-by: KOSAKI Motohiro Debugged-by: Benjamin Kidwell Signed-off-by: Daisuke Nishimura Signed-off-by: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 2 +- include/linux/mm_inline.h | 23 ++++--- include/linux/mmzone.h | 24 +++++++- include/linux/page-flags.h | 22 ++++++- include/linux/pagevec.h | 1 - include/linux/swap.h | 12 ++++ mm/Kconfig | 11 ++++ mm/internal.h | 26 ++++++++ mm/memcontrol.c | 73 +++++++++++++--------- mm/mempolicy.c | 2 +- mm/migrate.c | 31 +++++----- mm/swap.c | 42 +++++++++++-- mm/vmscan.c | 149 +++++++++++++++++++++++++++++++++++++++++---- 13 files changed, 345 insertions(+), 73 deletions(-) (limited to 'mm/internal.h') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 8d8f05c1515..ee1b2fcb441 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -34,9 +34,9 @@ extern int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask); extern int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask); +extern void mem_cgroup_move_lists(struct page *page, enum lru_list lru); extern void mem_cgroup_uncharge_page(struct page *page); extern void mem_cgroup_uncharge_cache_page(struct page *page); -extern void mem_cgroup_move_lists(struct page *page, bool active); extern int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask); extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h index f451fedd1e7..67d7697fd01 100644 --- a/include/linux/mm_inline.h +++ b/include/linux/mm_inline.h @@ -91,11 +91,16 @@ del_page_from_lru(struct zone *zone, struct page *page) enum lru_list l = LRU_BASE; list_del(&page->lru); - if (PageActive(page)) { - __ClearPageActive(page); - l += LRU_ACTIVE; + if (PageUnevictable(page)) { + __ClearPageUnevictable(page); + l = LRU_UNEVICTABLE; + } else { + if (PageActive(page)) { + __ClearPageActive(page); + l += LRU_ACTIVE; + } + l += page_is_file_cache(page); } - l += page_is_file_cache(page); __dec_zone_state(zone, NR_LRU_BASE + l); } @@ -110,9 +115,13 @@ static inline enum lru_list page_lru(struct page *page) { enum lru_list lru = LRU_BASE; - if (PageActive(page)) - lru += LRU_ACTIVE; - lru += page_is_file_cache(page); + if (PageUnevictable(page)) + lru = LRU_UNEVICTABLE; + else { + if (PageActive(page)) + lru += LRU_ACTIVE; + lru += page_is_file_cache(page); + } return lru; } diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 9c5111f49a3..d1f60d5fe2e 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -86,6 +86,11 @@ enum zone_stat_item { NR_ACTIVE_ANON, /* " " " " " */ NR_INACTIVE_FILE, /* " " " " " */ NR_ACTIVE_FILE, /* " " " " " */ +#ifdef CONFIG_UNEVICTABLE_LRU + NR_UNEVICTABLE, /* " " " " " */ +#else + NR_UNEVICTABLE = NR_ACTIVE_FILE, /* avoid compiler errors in dead code */ +#endif NR_ANON_PAGES, /* Mapped anonymous pages */ NR_FILE_MAPPED, /* pagecache pages mapped into pagetables. only modified from process context */ @@ -128,10 +133,18 @@ enum lru_list { LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE, LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE, LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE, - NR_LRU_LISTS }; +#ifdef CONFIG_UNEVICTABLE_LRU + LRU_UNEVICTABLE, +#else + LRU_UNEVICTABLE = LRU_ACTIVE_FILE, /* avoid compiler errors in dead code */ +#endif + NR_LRU_LISTS +}; #define for_each_lru(l) for (l = 0; l < NR_LRU_LISTS; l++) +#define for_each_evictable_lru(l) for (l = 0; l <= LRU_ACTIVE_FILE; l++) + static inline int is_file_lru(enum lru_list l) { return (l == LRU_INACTIVE_FILE || l == LRU_ACTIVE_FILE); @@ -142,6 +155,15 @@ static inline int is_active_lru(enum lru_list l) return (l == LRU_ACTIVE_ANON || l == LRU_ACTIVE_FILE); } +static inline int is_unevictable_lru(enum lru_list l) +{ +#ifdef CONFIG_UNEVICTABLE_LRU + return (l == LRU_UNEVICTABLE); +#else + return 0; +#endif +} + struct per_cpu_pages { int count; /* number of pages in the list */ int high; /* high watermark, emptying needed */ diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 3d31616dcd2..ec1a1baad34 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -94,6 +94,9 @@ enum pageflags { PG_reclaim, /* To be reclaimed asap */ PG_buddy, /* Page is free, on buddy lists */ PG_swapbacked, /* Page is backed by RAM/swap */ +#ifdef CONFIG_UNEVICTABLE_LRU + PG_unevictable, /* Page is "unevictable" */ +#endif #ifdef CONFIG_IA64_UNCACHED_ALLOCATOR PG_uncached, /* Page has been mapped as uncached */ #endif @@ -182,6 +185,7 @@ PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced) PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty) PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru) PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active) + TESTCLEARFLAG(Active, active) __PAGEFLAG(Slab, slab) PAGEFLAG(Checked, checked) /* Used by some filesystems */ PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */ @@ -225,6 +229,15 @@ PAGEFLAG(SwapCache, swapcache) PAGEFLAG_FALSE(SwapCache) #endif +#ifdef CONFIG_UNEVICTABLE_LRU +PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable) + TESTCLEARFLAG(Unevictable, unevictable) +#else +PAGEFLAG_FALSE(Unevictable) TESTCLEARFLAG_FALSE(Unevictable) + SETPAGEFLAG_NOOP(Unevictable) CLEARPAGEFLAG_NOOP(Unevictable) + __CLEARPAGEFLAG_NOOP(Unevictable) +#endif + #ifdef CONFIG_IA64_UNCACHED_ALLOCATOR PAGEFLAG(Uncached, uncached) #else @@ -340,9 +353,16 @@ static inline void __ClearPageTail(struct page *page) #endif /* !PAGEFLAGS_EXTENDED */ +#ifdef CONFIG_UNEVICTABLE_LRU +#define __PG_UNEVICTABLE (1 << PG_unevictable) +#else +#define __PG_UNEVICTABLE 0 +#endif + #define PAGE_FLAGS (1 << PG_lru | 1 << PG_private | 1 << PG_locked | \ 1 << PG_buddy | 1 << PG_writeback | \ - 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active) + 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \ + __PG_UNEVICTABLE) /* * Flags checked in bad_page(). Pages on the free list should not have diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h index 5fc96a4e760..e90a2cb0291 100644 --- a/include/linux/pagevec.h +++ b/include/linux/pagevec.h @@ -101,7 +101,6 @@ static inline void __pagevec_lru_add_active_file(struct pagevec *pvec) ____pagevec_lru_add(pvec, LRU_ACTIVE_FILE); } - static inline void pagevec_lru_add_file(struct pagevec *pvec) { if (pagevec_count(pvec)) diff --git a/include/linux/swap.h b/include/linux/swap.h index 7d09d79997a..a2113044d20 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -180,6 +180,8 @@ extern int lru_add_drain_all(void); extern void rotate_reclaimable_page(struct page *page); extern void swap_setup(void); +extern void add_page_to_unevictable_list(struct page *page); + /** * lru_cache_add: add a page to the page lists * @page: the page to add @@ -228,6 +230,16 @@ static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order) } #endif +#ifdef CONFIG_UNEVICTABLE_LRU +extern int page_evictable(struct page *page, struct vm_area_struct *vma); +#else +static inline int page_evictable(struct page *page, + struct vm_area_struct *vma) +{ + return 1; +} +#endif + extern int kswapd_run(int nid); #ifdef CONFIG_MMU diff --git a/mm/Kconfig b/mm/Kconfig index 1a501a4de95..5b5790f8a81 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -209,5 +209,16 @@ config VIRT_TO_BUS def_bool y depends on !ARCH_NO_VIRT_TO_BUS +config UNEVICTABLE_LRU + bool "Add LRU list to track non-evictable pages" + default y + depends on MMU + help + Keeps unevictable pages off of the active and inactive pageout + lists, so kswapd will not waste CPU time or have its balancing + algorithms thrown off by scanning these pages. Selecting this + will use one page flag and increase the code size a little, + say Y unless you know what you are doing. + config MMU_NOTIFIER bool diff --git a/mm/internal.h b/mm/internal.h index 4e8e78b978b..3db17b2a1ac 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -39,8 +39,15 @@ static inline void __put_page(struct page *page) atomic_dec(&page->_count); } +/* + * in mm/vmscan.c: + */ extern int isolate_lru_page(struct page *page); +extern void putback_lru_page(struct page *page); +/* + * in mm/page_alloc.c + */ extern void __free_pages_bootmem(struct page *page, unsigned int order); /* @@ -54,6 +61,25 @@ static inline unsigned long page_order(struct page *page) return page_private(page); } +#ifdef CONFIG_UNEVICTABLE_LRU +/* + * unevictable_migrate_page() called only from migrate_page_copy() to + * migrate unevictable flag to new page. + * Note that the old page has been isolated from the LRU lists at this + * point so we don't need to worry about LRU statistics. + */ +static inline void unevictable_migrate_page(struct page *new, struct page *old) +{ + if (TestClearPageUnevictable(old)) + SetPageUnevictable(new); +} +#else +static inline void unevictable_migrate_page(struct page *new, struct page *old) +{ +} +#endif + + /* * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node, * so all functions starting at paging_init should be marked __init diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 27e9e75f4ea..82c065e7551 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -160,9 +160,10 @@ struct page_cgroup { struct mem_cgroup *mem_cgroup; int flags; }; -#define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */ -#define PAGE_CGROUP_FLAG_ACTIVE (0x2) /* page is active in this cgroup */ -#define PAGE_CGROUP_FLAG_FILE (0x4) /* page is file system backed */ +#define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */ +#define PAGE_CGROUP_FLAG_ACTIVE (0x2) /* page is active in this cgroup */ +#define PAGE_CGROUP_FLAG_FILE (0x4) /* page is file system backed */ +#define PAGE_CGROUP_FLAG_UNEVICTABLE (0x8) /* page is unevictableable */ static int page_cgroup_nid(struct page_cgroup *pc) { @@ -292,10 +293,14 @@ static void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz, { int lru = LRU_BASE; - if (pc->flags & PAGE_CGROUP_FLAG_ACTIVE) - lru += LRU_ACTIVE; - if (pc->flags & PAGE_CGROUP_FLAG_FILE) - lru += LRU_FILE; + if (pc->flags & PAGE_CGROUP_FLAG_UNEVICTABLE) + lru = LRU_UNEVICTABLE; + else { + if (pc->flags & PAGE_CGROUP_FLAG_ACTIVE) + lru += LRU_ACTIVE; + if (pc->flags & PAGE_CGROUP_FLAG_FILE) + lru += LRU_FILE; + } MEM_CGROUP_ZSTAT(mz, lru) -= 1; @@ -308,10 +313,14 @@ static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz, { int lru = LRU_BASE; - if (pc->flags & PAGE_CGROUP_FLAG_ACTIVE) - lru += LRU_ACTIVE; - if (pc->flags & PAGE_CGROUP_FLAG_FILE) - lru += LRU_FILE; + if (pc->flags & PAGE_CGROUP_FLAG_UNEVICTABLE) + lru = LRU_UNEVICTABLE; + else { + if (pc->flags & PAGE_CGROUP_FLAG_ACTIVE) + lru += LRU_ACTIVE; + if (pc->flags & PAGE_CGROUP_FLAG_FILE) + lru += LRU_FILE; + } MEM_CGROUP_ZSTAT(mz, lru) += 1; list_add(&pc->lru, &mz->lists[lru]); @@ -319,21 +328,31 @@ static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz, mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, true); } -static void __mem_cgroup_move_lists(struct page_cgroup *pc, bool active) +static void __mem_cgroup_move_lists(struct page_cgroup *pc, enum lru_list lru) { struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc); - int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE; - int file = pc->flags & PAGE_CGROUP_FLAG_FILE; - int lru = LRU_FILE * !!file + !!from; + int active = pc->flags & PAGE_CGROUP_FLAG_ACTIVE; + int file = pc->flags & PAGE_CGROUP_FLAG_FILE; + int unevictable = pc->flags & PAGE_CGROUP_FLAG_UNEVICTABLE; + enum lru_list from = unevictable ? LRU_UNEVICTABLE : + (LRU_FILE * !!file + !!active); - MEM_CGROUP_ZSTAT(mz, lru) -= 1; + if (lru == from) + return; - if (active) - pc->flags |= PAGE_CGROUP_FLAG_ACTIVE; - else + MEM_CGROUP_ZSTAT(mz, from) -= 1; + + if (is_unevictable_lru(lru)) { pc->flags &= ~PAGE_CGROUP_FLAG_ACTIVE; + pc->flags |= PAGE_CGROUP_FLAG_UNEVICTABLE; + } else { + if (is_active_lru(lru)) + pc->flags |= PAGE_CGROUP_FLAG_ACTIVE; + else + pc->flags &= ~PAGE_CGROUP_FLAG_ACTIVE; + pc->flags &= ~PAGE_CGROUP_FLAG_UNEVICTABLE; + } - lru = LRU_FILE * !!file + !!active; MEM_CGROUP_ZSTAT(mz, lru) += 1; list_move(&pc->lru, &mz->lists[lru]); } @@ -351,7 +370,7 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) /* * This routine assumes that the appropriate zone's lru lock is already held */ -void mem_cgroup_move_lists(struct page *page, bool active) +void mem_cgroup_move_lists(struct page *page, enum lru_list lru) { struct page_cgroup *pc; struct mem_cgroup_per_zone *mz; @@ -374,7 +393,7 @@ void mem_cgroup_move_lists(struct page *page, bool active) if (pc) { mz = page_cgroup_zoneinfo(pc); spin_lock_irqsave(&mz->lru_lock, flags); - __mem_cgroup_move_lists(pc, active); + __mem_cgroup_move_lists(pc, lru); spin_unlock_irqrestore(&mz->lru_lock, flags); } unlock_page_cgroup(page); @@ -472,12 +491,10 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, /* * TODO: play better with lumpy reclaim, grabbing anything. */ - if (PageActive(page) && !active) { - __mem_cgroup_move_lists(pc, true); - continue; - } - if (!PageActive(page) && active) { - __mem_cgroup_move_lists(pc, false); + if (PageUnevictable(page) || + (PageActive(page) && !active) || + (!PageActive(page) && active)) { + __mem_cgroup_move_lists(pc, page_lru(page)); continue; } diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 71b47491487..36f42573a33 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2202,7 +2202,7 @@ static void gather_stats(struct page *page, void *private, int pte_dirty) if (PageSwapCache(page)) md->swapcache++; - if (PageActive(page)) + if (PageActive(page) || PageUnevictable(page)) md->active++; if (PageWriteback(page)) diff --git a/mm/migrate.c b/mm/migrate.c index c0732748711..b10237d8b45 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -53,14 +53,9 @@ int migrate_prep(void) return 0; } -static inline void move_to_lru(struct page *page) -{ - lru_cache_add_lru(page, page_lru(page)); - put_page(page); -} - /* - * Add isolated pages on the list back to the LRU. + * Add isolated pages on the list back to the LRU under page lock + * to avoid leaking evictable pages back onto unevictable list. * * returns the number of pages put back. */ @@ -72,7 +67,7 @@ int putback_lru_pages(struct list_head *l) list_for_each_entry_safe(page, page2, l, lru) { list_del(&page->lru); - move_to_lru(page); + putback_lru_page(page); count++; } return count; @@ -354,8 +349,11 @@ static void migrate_page_copy(struct page *newpage, struct page *page) SetPageReferenced(newpage); if (PageUptodate(page)) SetPageUptodate(newpage); - if (PageActive(page)) + if (TestClearPageActive(page)) { + VM_BUG_ON(PageUnevictable(page)); SetPageActive(newpage); + } else + unevictable_migrate_page(newpage, page); if (PageChecked(page)) SetPageChecked(newpage); if (PageMappedToDisk(page)) @@ -376,7 +374,6 @@ static void migrate_page_copy(struct page *newpage, struct page *page) #ifdef CONFIG_SWAP ClearPageSwapCache(page); #endif - ClearPageActive(page); ClearPagePrivate(page); set_page_private(page, 0); page->mapping = NULL; @@ -555,6 +552,10 @@ static int fallback_migrate_page(struct address_space *mapping, * * The new page will have replaced the old page if this function * is successful. + * + * Return value: + * < 0 - error code + * == 0 - success */ static int move_to_new_page(struct page *newpage, struct page *page) { @@ -617,9 +618,10 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, if (!newpage) return -ENOMEM; - if (page_count(page) == 1) + if (page_count(page) == 1) { /* page was freed from under us. So we are done. */ goto move_newpage; + } charge = mem_cgroup_prepare_migration(page, newpage); if (charge == -ENOMEM) { @@ -693,7 +695,6 @@ rcu_unlock: rcu_read_unlock(); unlock: - unlock_page(page); if (rc != -EAGAIN) { @@ -704,17 +705,19 @@ unlock: * restored. */ list_del(&page->lru); - move_to_lru(page); + putback_lru_page(page); } move_newpage: if (!charge) mem_cgroup_end_migration(newpage); + /* * Move the new page to the LRU. If migration was not successful * then this will free the page. */ - move_to_lru(newpage); + putback_lru_page(newpage); + if (result) { if (rc) *result = rc; diff --git a/mm/swap.c b/mm/swap.c index 0b1974a0897..fee6b973f14 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -115,7 +115,7 @@ static void pagevec_move_tail(struct pagevec *pvec) zone = pagezone; spin_lock(&zone->lru_lock); } - if (PageLRU(page) && !PageActive(page)) { + if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { int lru = page_is_file_cache(page); list_move_tail(&page->lru, &zone->lru[lru].list); pgmoved++; @@ -136,7 +136,7 @@ static void pagevec_move_tail(struct pagevec *pvec) void rotate_reclaimable_page(struct page *page) { if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) && - PageLRU(page)) { + !PageUnevictable(page) && PageLRU(page)) { struct pagevec *pvec; unsigned long flags; @@ -157,7 +157,7 @@ void activate_page(struct page *page) struct zone *zone = page_zone(page); spin_lock_irq(&zone->lru_lock); - if (PageLRU(page) && !PageActive(page)) { + if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { int file = page_is_file_cache(page); int lru = LRU_BASE + file; del_page_from_lru_list(zone, page, lru); @@ -166,7 +166,7 @@ void activate_page(struct page *page) lru += LRU_ACTIVE; add_page_to_lru_list(zone, page, lru); __count_vm_event(PGACTIVATE); - mem_cgroup_move_lists(page, true); + mem_cgroup_move_lists(page, lru); zone->recent_rotated[!!file]++; zone->recent_scanned[!!file]++; @@ -183,7 +183,8 @@ void activate_page(struct page *page) */ void mark_page_accessed(struct page *page) { - if (!PageActive(page) && PageReferenced(page) && PageLRU(page)) { + if (!PageActive(page) && !PageUnevictable(page) && + PageReferenced(page) && PageLRU(page)) { activate_page(page); ClearPageReferenced(page); } else if (!PageReferenced(page)) { @@ -211,13 +212,38 @@ void __lru_cache_add(struct page *page, enum lru_list lru) void lru_cache_add_lru(struct page *page, enum lru_list lru) { if (PageActive(page)) { + VM_BUG_ON(PageUnevictable(page)); ClearPageActive(page); + } else if (PageUnevictable(page)) { + VM_BUG_ON(PageActive(page)); + ClearPageUnevictable(page); } - VM_BUG_ON(PageLRU(page) || PageActive(page)); + VM_BUG_ON(PageLRU(page) || PageActive(page) || PageUnevictable(page)); __lru_cache_add(page, lru); } +/** + * add_page_to_unevictable_list - add a page to the unevictable list + * @page: the page to be added to the unevictable list + * + * Add page directly to its zone's unevictable list. To avoid races with + * tasks that might be making the page evictable, through eg. munlock, + * munmap or exit, while it's not on the lru, we want to add the page + * while it's locked or otherwise "invisible" to other tasks. This is + * difficult to do when using the pagevec cache, so bypass that. + */ +void add_page_to_unevictable_list(struct page *page) +{ + struct zone *zone = page_zone(page); + + spin_lock_irq(&zone->lru_lock); + SetPageUnevictable(page); + SetPageLRU(page); + add_page_to_lru_list(zone, page, LRU_UNEVICTABLE); + spin_unlock_irq(&zone->lru_lock); +} + /* * Drain pages out of the cpu's pagevecs. * Either "cpu" is the current CPU, and preemption has already been @@ -316,6 +342,7 @@ void release_pages(struct page **pages, int nr, int cold) if (PageLRU(page)) { struct zone *pagezone = page_zone(page); + if (pagezone != zone) { if (zone) spin_unlock_irqrestore(&zone->lru_lock, @@ -392,6 +419,7 @@ void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru) { int i; struct zone *zone = NULL; + VM_BUG_ON(is_unevictable_lru(lru)); for (i = 0; i < pagevec_count(pvec); i++) { struct page *page = pvec->pages[i]; @@ -403,6 +431,8 @@ void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru) zone = pagezone; spin_lock_irq(&zone->lru_lock); } + VM_BUG_ON(PageActive(page)); + VM_BUG_ON(PageUnevictable(page)); VM_BUG_ON(PageLRU(page)); SetPageLRU(page); if (is_active_lru(lru)) diff --git a/mm/vmscan.c b/mm/vmscan.c index a8347b677e7..154b9b608da 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -470,6 +470,79 @@ int remove_mapping(struct address_space *mapping, struct page *page) return 0; } +/** + * putback_lru_page - put previously isolated page onto appropriate LRU list + * @page: page to be put back to appropriate lru list + * + * Add previously isolated @page to appropriate LRU list. + * Page may still be unevictable for other reasons. + * + * lru_lock must not be held, interrupts must be enabled. + */ +#ifdef CONFIG_UNEVICTABLE_LRU +void putback_lru_page(struct page *page) +{ + int lru; + int active = !!TestClearPageActive(page); + + VM_BUG_ON(PageLRU(page)); + +redo: + ClearPageUnevictable(page); + + if (page_evictable(page, NULL)) { + /* + * For evictable pages, we can use the cache. + * In event of a race, worst case is we end up with an + * unevictable page on [in]active list. + * We know how to handle that. + */ + lru = active + page_is_file_cache(page); + lru_cache_add_lru(page, lru); + } else { + /* + * Put unevictable pages directly on zone's unevictable + * list. + */ + lru = LRU_UNEVICTABLE; + add_page_to_unevictable_list(page); + } + mem_cgroup_move_lists(page, lru); + + /* + * page's status can change while we move it among lru. If an evictable + * page is on unevictable list, it never be freed. To avoid that, + * check after we added it to the list, again. + */ + if (lru == LRU_UNEVICTABLE && page_evictable(page, NULL)) { + if (!isolate_lru_page(page)) { + put_page(page); + goto redo; + } + /* This means someone else dropped this page from LRU + * So, it will be freed or putback to LRU again. There is + * nothing to do here. + */ + } + + put_page(page); /* drop ref from isolate */ +} + +#else /* CONFIG_UNEVICTABLE_LRU */ + +void putback_lru_page(struct page *page) +{ + int lru; + VM_BUG_ON(PageLRU(page)); + + lru = !!TestClearPageActive(page) + page_is_file_cache(page); + lru_cache_add_lru(page, lru); + mem_cgroup_move_lists(page, lru); + put_page(page); +} +#endif /* CONFIG_UNEVICTABLE_LRU */ + + /* * shrink_page_list() returns the number of reclaimed pages */ @@ -503,6 +576,12 @@ static unsigned long shrink_page_list(struct list_head *page_list, sc->nr_scanned++; + if (unlikely(!page_evictable(page, NULL))) { + unlock_page(page); + putback_lru_page(page); + continue; + } + if (!sc->may_swap && page_mapped(page)) goto keep_locked; @@ -602,7 +681,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, * possible for a page to have PageDirty set, but it is actually * clean (all its buffers are clean). This happens if the * buffers were written out directly, with submit_bh(). ext3 - * will do this, as well as the blockdev mapping. + * will do this, as well as the blockdev mapping. * try_to_release_page() will discover that cleanness and will * drop the buffers and mark the page clean - it can be freed. * @@ -650,6 +729,7 @@ activate_locked: /* Not a candidate for swapping, so reclaim swap space. */ if (PageSwapCache(page) && vm_swap_full()) remove_exclusive_swap_page_ref(page); + VM_BUG_ON(PageActive(page)); SetPageActive(page); pgactivate++; keep_locked: @@ -699,6 +779,14 @@ int __isolate_lru_page(struct page *page, int mode, int file) if (mode != ISOLATE_BOTH && (!page_is_file_cache(page) != !file)) return ret; + /* + * When this function is being called for lumpy reclaim, we + * initially look into all LRU pages, active, inactive and + * unevictable; only give shrink_page_list evictable pages. + */ + if (PageUnevictable(page)) + return ret; + ret = -EBUSY; if (likely(get_page_unless_zero(page))) { /* @@ -810,7 +898,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, /* else it is being freed elsewhere */ list_move(&cursor_page->lru, src); default: - break; + break; /* ! on LRU or wrong list */ } } } @@ -870,8 +958,9 @@ static unsigned long clear_active_flags(struct list_head *page_list, * Returns -EBUSY if the page was not on an LRU list. * * The returned page will have PageLRU() cleared. If it was found on - * the active list, it will have PageActive set. That flag may need - * to be cleared by the caller before letting the page go. + * the active list, it will have PageActive set. If it was found on + * the unevictable list, it will have the PageUnevictable bit set. That flag + * may need to be cleared by the caller before letting the page go. * * The vmstat statistic corresponding to the list on which the page was * found will be decremented. @@ -892,11 +981,10 @@ int isolate_lru_page(struct page *page) spin_lock_irq(&zone->lru_lock); if (PageLRU(page) && get_page_unless_zero(page)) { - int lru = LRU_BASE; + int lru = page_lru(page); ret = 0; ClearPageLRU(page); - lru += page_is_file_cache(page) + !!PageActive(page); del_page_from_lru_list(zone, page, lru); } spin_unlock_irq(&zone->lru_lock); @@ -1008,11 +1096,20 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, * Put back any unfreeable pages. */ while (!list_empty(&page_list)) { + int lru; page = lru_to_page(&page_list); VM_BUG_ON(PageLRU(page)); - SetPageLRU(page); list_del(&page->lru); - add_page_to_lru_list(zone, page, page_lru(page)); + if (unlikely(!page_evictable(page, NULL))) { + spin_unlock_irq(&zone->lru_lock); + putback_lru_page(page); + spin_lock_irq(&zone->lru_lock); + continue; + } + SetPageLRU(page); + lru = page_lru(page); + add_page_to_lru_list(zone, page, lru); + mem_cgroup_move_lists(page, lru); if (PageActive(page) && scan_global_lru(sc)) { int file = !!page_is_file_cache(page); zone->recent_rotated[file]++; @@ -1107,6 +1204,11 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone, page = lru_to_page(&l_hold); list_del(&page->lru); + if (unlikely(!page_evictable(page, NULL))) { + putback_lru_page(page); + continue; + } + /* page_referenced clears PageReferenced */ if (page_mapping_inuse(page) && page_referenced(page, 0, sc->mem_cgroup)) @@ -1140,7 +1242,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone, ClearPageActive(page); list_move(&page->lru, &zone->lru[lru].list); - mem_cgroup_move_lists(page, false); + mem_cgroup_move_lists(page, lru); pgmoved++; if (!pagevec_add(&pvec, page)) { __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved); @@ -1286,7 +1388,7 @@ static unsigned long shrink_zone(int priority, struct zone *zone, get_scan_ratio(zone, sc, percent); - for_each_lru(l) { + for_each_evictable_lru(l) { if (scan_global_lru(sc)) { int file = is_file_lru(l); int scan; @@ -1318,7 +1420,7 @@ static unsigned long shrink_zone(int priority, struct zone *zone, while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] || nr[LRU_INACTIVE_FILE]) { - for_each_lru(l) { + for_each_evictable_lru(l) { if (nr[l]) { nr_to_scan = min(nr[l], (unsigned long)sc->swap_cluster_max); @@ -1875,8 +1977,8 @@ static unsigned long shrink_all_zones(unsigned long nr_pages, int prio, if (zone_is_all_unreclaimable(zone) && prio != DEF_PRIORITY) continue; - for_each_lru(l) { - /* For pass = 0 we don't shrink the active list */ + for_each_evictable_lru(l) { + /* For pass = 0, we don't shrink the active list */ if (pass == 0 && (l == LRU_ACTIVE || l == LRU_ACTIVE_FILE)) continue; @@ -2213,3 +2315,24 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) return ret; } #endif + +#ifdef CONFIG_UNEVICTABLE_LRU +/* + * page_evictable - test whether a page is evictable + * @page: the page to test + * @vma: the VMA in which the page is or will be mapped, may be NULL + * + * Test whether page is evictable--i.e., should be placed on active/inactive + * lists vs unevictable list. + * + * Reasons page might not be evictable: + * TODO - later patches + */ +int page_evictable(struct page *page, struct vm_area_struct *vma) +{ + + /* TODO: test page [!]evictable conditions */ + + return 1; +} +#endif -- cgit v1.2.3-70-g09d2 From b291f000393f5a0b679012b39d79fbc85c018233 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Sat, 18 Oct 2008 20:26:44 -0700 Subject: mlock: mlocked pages are unevictable Make sure that mlocked pages also live on the unevictable LRU, so kswapd will not scan them over and over again. This is achieved through various strategies: 1) add yet another page flag--PG_mlocked--to indicate that the page is locked for efficient testing in vmscan and, optionally, fault path. This allows early culling of unevictable pages, preventing them from getting to page_referenced()/try_to_unmap(). Also allows separate accounting of mlock'd pages, as Nick's original patch did. Note: Nick's original mlock patch used a PG_mlocked flag. I had removed this in favor of the PG_unevictable flag + an mlock_count [new page struct member]. I restored the PG_mlocked flag to eliminate the new count field. 2) add the mlock/unevictable infrastructure to mm/mlock.c, with internal APIs in mm/internal.h. This is a rework of Nick's original patch to these files, taking into account that mlocked pages are now kept on unevictable LRU list. 3) update vmscan.c:page_evictable() to check PageMlocked() and, if vma passed in, the vm_flags. Note that the vma will only be passed in for new pages in the fault path; and then only if the "cull unevictable pages in fault path" patch is included. 4) add try_to_unlock() to rmap.c to walk a page's rmap and ClearPageMlocked() if no other vmas have it mlocked. Reuses as much of try_to_unmap() as possible. This effectively replaces the use of one of the lru list links as an mlock count. If this mechanism let's pages in mlocked vmas leak through w/o PG_mlocked set [I don't know that it does], we should catch them later in try_to_unmap(). One hopes this will be rare, as it will be relatively expensive. Original mm/internal.h, mm/rmap.c and mm/mlock.c changes: Signed-off-by: Nick Piggin splitlru: introduce __get_user_pages(): New munlock processing need to GUP_FLAGS_IGNORE_VMA_PERMISSIONS. because current get_user_pages() can't grab PROT_NONE pages theresore it cause PROT_NONE pages can't munlock. [akpm@linux-foundation.org: fix this for pagemap-pass-mm-into-pagewalkers.patch] [akpm@linux-foundation.org: untangle patch interdependencies] [akpm@linux-foundation.org: fix things after out-of-order merging] [hugh@veritas.com: fix page-flags mess] [lee.schermerhorn@hp.com: fix munlock page table walk - now requires 'mm'] [kosaki.motohiro@jp.fujitsu.com: build fix] [kosaki.motohiro@jp.fujitsu.com: fix truncate race and sevaral comments] [kosaki.motohiro@jp.fujitsu.com: splitlru: introduce __get_user_pages()] Signed-off-by: KOSAKI Motohiro Signed-off-by: Rik van Riel Signed-off-by: Lee Schermerhorn Cc: Nick Piggin Cc: Dave Hansen Cc: Matt Mackall Signed-off-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mm.h | 5 + include/linux/page-flags.h | 19 ++- include/linux/rmap.h | 14 ++ mm/internal.h | 71 ++++++++ mm/memory.c | 56 ++++++- mm/migrate.c | 2 + mm/mlock.c | 394 ++++++++++++++++++++++++++++++++++++++++++--- mm/mmap.c | 2 - mm/nommu.c | 44 +++-- mm/page_alloc.c | 6 +- mm/rmap.c | 257 ++++++++++++++++++++++++----- mm/swap.c | 2 +- mm/vmscan.c | 36 +++-- 13 files changed, 817 insertions(+), 91 deletions(-) (limited to 'mm/internal.h') diff --git a/include/linux/mm.h b/include/linux/mm.h index 40236290e2a..ffee2f74341 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -131,6 +131,11 @@ extern unsigned int kobjsize(const void *objp); #define VM_SequentialReadHint(v) ((v)->vm_flags & VM_SEQ_READ) #define VM_RandomReadHint(v) ((v)->vm_flags & VM_RAND_READ) +/* + * special vmas that are non-mergable, non-mlock()able + */ +#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP) + /* * mapping from the currently active vm_flags protection bits (the * low four bits) to a page protection mask.. diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index ec1a1baad34..b12f93a3c34 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -96,6 +96,7 @@ enum pageflags { PG_swapbacked, /* Page is backed by RAM/swap */ #ifdef CONFIG_UNEVICTABLE_LRU PG_unevictable, /* Page is "unevictable" */ + PG_mlocked, /* Page is vma mlocked */ #endif #ifdef CONFIG_IA64_UNCACHED_ALLOCATOR PG_uncached, /* Page has been mapped as uncached */ @@ -232,7 +233,17 @@ PAGEFLAG_FALSE(SwapCache) #ifdef CONFIG_UNEVICTABLE_LRU PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable) TESTCLEARFLAG(Unevictable, unevictable) + +#define MLOCK_PAGES 1 +PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked) + TESTSCFLAG(Mlocked, mlocked) + #else + +#define MLOCK_PAGES 0 +PAGEFLAG_FALSE(Mlocked) + SETPAGEFLAG_NOOP(Mlocked) TESTCLEARFLAG_FALSE(Mlocked) + PAGEFLAG_FALSE(Unevictable) TESTCLEARFLAG_FALSE(Unevictable) SETPAGEFLAG_NOOP(Unevictable) CLEARPAGEFLAG_NOOP(Unevictable) __CLEARPAGEFLAG_NOOP(Unevictable) @@ -354,15 +365,17 @@ static inline void __ClearPageTail(struct page *page) #endif /* !PAGEFLAGS_EXTENDED */ #ifdef CONFIG_UNEVICTABLE_LRU -#define __PG_UNEVICTABLE (1 << PG_unevictable) +#define __PG_UNEVICTABLE (1 << PG_unevictable) +#define __PG_MLOCKED (1 << PG_mlocked) #else -#define __PG_UNEVICTABLE 0 +#define __PG_UNEVICTABLE 0 +#define __PG_MLOCKED 0 #endif #define PAGE_FLAGS (1 << PG_lru | 1 << PG_private | 1 << PG_locked | \ 1 << PG_buddy | 1 << PG_writeback | \ 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \ - __PG_UNEVICTABLE) + __PG_UNEVICTABLE | __PG_MLOCKED) /* * Flags checked in bad_page(). Pages on the free list should not have diff --git a/include/linux/rmap.h b/include/linux/rmap.h index fed6f5e0b41..955667e6a52 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -117,6 +117,19 @@ unsigned long page_address_in_vma(struct page *, struct vm_area_struct *); */ int page_mkclean(struct page *); +#ifdef CONFIG_UNEVICTABLE_LRU +/* + * called in munlock()/munmap() path to check for other vmas holding + * the page mlocked. + */ +int try_to_munlock(struct page *); +#else +static inline int try_to_munlock(struct page *page) +{ + return 0; /* a.k.a. SWAP_SUCCESS */ +} +#endif + #else /* !CONFIG_MMU */ #define anon_vma_init() do {} while (0) @@ -140,5 +153,6 @@ static inline int page_mkclean(struct page *page) #define SWAP_SUCCESS 0 #define SWAP_AGAIN 1 #define SWAP_FAIL 2 +#define SWAP_MLOCK 3 #endif /* _LINUX_RMAP_H */ diff --git a/mm/internal.h b/mm/internal.h index 3db17b2a1ac..4ebf0bef9a3 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -61,6 +61,10 @@ static inline unsigned long page_order(struct page *page) return page_private(page); } +extern int mlock_vma_pages_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end); +extern void munlock_vma_pages_all(struct vm_area_struct *vma); + #ifdef CONFIG_UNEVICTABLE_LRU /* * unevictable_migrate_page() called only from migrate_page_copy() to @@ -79,6 +83,65 @@ static inline void unevictable_migrate_page(struct page *new, struct page *old) } #endif +#ifdef CONFIG_UNEVICTABLE_LRU +/* + * Called only in fault path via page_evictable() for a new page + * to determine if it's being mapped into a LOCKED vma. + * If so, mark page as mlocked. + */ +static inline int is_mlocked_vma(struct vm_area_struct *vma, struct page *page) +{ + VM_BUG_ON(PageLRU(page)); + + if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED)) + return 0; + + SetPageMlocked(page); + return 1; +} + +/* + * must be called with vma's mmap_sem held for read, and page locked. + */ +extern void mlock_vma_page(struct page *page); + +/* + * Clear the page's PageMlocked(). This can be useful in a situation where + * we want to unconditionally remove a page from the pagecache -- e.g., + * on truncation or freeing. + * + * It is legal to call this function for any page, mlocked or not. + * If called for a page that is still mapped by mlocked vmas, all we do + * is revert to lazy LRU behaviour -- semantics are not broken. + */ +extern void __clear_page_mlock(struct page *page); +static inline void clear_page_mlock(struct page *page) +{ + if (unlikely(TestClearPageMlocked(page))) + __clear_page_mlock(page); +} + +/* + * mlock_migrate_page - called only from migrate_page_copy() to + * migrate the Mlocked page flag + */ +static inline void mlock_migrate_page(struct page *newpage, struct page *page) +{ + if (TestClearPageMlocked(page)) + SetPageMlocked(newpage); +} + + +#else /* CONFIG_UNEVICTABLE_LRU */ +static inline int is_mlocked_vma(struct vm_area_struct *v, struct page *p) +{ + return 0; +} +static inline void clear_page_mlock(struct page *page) { } +static inline void mlock_vma_page(struct page *page) { } +static inline void mlock_migrate_page(struct page *new, struct page *old) { } + +#endif /* CONFIG_UNEVICTABLE_LRU */ /* * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node, @@ -148,4 +211,12 @@ static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn, } #endif /* CONFIG_SPARSEMEM */ +#define GUP_FLAGS_WRITE 0x1 +#define GUP_FLAGS_FORCE 0x2 +#define GUP_FLAGS_IGNORE_VMA_PERMISSIONS 0x4 + +int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, + unsigned long start, int len, int flags, + struct page **pages, struct vm_area_struct **vmas); + #endif diff --git a/mm/memory.c b/mm/memory.c index 71cdefd1ef1..9fef7272fb9 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -64,6 +64,8 @@ #include "internal.h" +#include "internal.h" + #ifndef CONFIG_NEED_MULTIPLE_NODES /* use the per-pgdat data instead for discontigmem - mbligh */ unsigned long max_mapnr; @@ -1129,12 +1131,17 @@ static inline int use_zero_page(struct vm_area_struct *vma) return !vma->vm_ops || !vma->vm_ops->fault; } -int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, - unsigned long start, int len, int write, int force, + + +int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, + unsigned long start, int len, int flags, struct page **pages, struct vm_area_struct **vmas) { int i; - unsigned int vm_flags; + unsigned int vm_flags = 0; + int write = !!(flags & GUP_FLAGS_WRITE); + int force = !!(flags & GUP_FLAGS_FORCE); + int ignore = !!(flags & GUP_FLAGS_IGNORE_VMA_PERMISSIONS); if (len <= 0) return 0; @@ -1158,7 +1165,9 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, pud_t *pud; pmd_t *pmd; pte_t *pte; - if (write) /* user gate pages are read-only */ + + /* user gate pages are read-only */ + if (!ignore && write) return i ? : -EFAULT; if (pg > TASK_SIZE) pgd = pgd_offset_k(pg); @@ -1190,8 +1199,9 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, continue; } - if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP)) - || !(vm_flags & vma->vm_flags)) + if (!vma || + (vma->vm_flags & (VM_IO | VM_PFNMAP)) || + (!ignore && !(vm_flags & vma->vm_flags))) return i ? : -EFAULT; if (is_vm_hugetlb_page(vma)) { @@ -1266,6 +1276,23 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, } while (len); return i; } + +int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, + unsigned long start, int len, int write, int force, + struct page **pages, struct vm_area_struct **vmas) +{ + int flags = 0; + + if (write) + flags |= GUP_FLAGS_WRITE; + if (force) + flags |= GUP_FLAGS_FORCE; + + return __get_user_pages(tsk, mm, + start, len, flags, + pages, vmas); +} + EXPORT_SYMBOL(get_user_pages); pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr, @@ -1858,6 +1885,15 @@ gotten: new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); if (!new_page) goto oom; + /* + * Don't let another task, with possibly unlocked vma, + * keep the mlocked page. + */ + if (vma->vm_flags & VM_LOCKED) { + lock_page(old_page); /* for LRU manipulation */ + clear_page_mlock(old_page); + unlock_page(old_page); + } cow_user_page(new_page, old_page, address, vma); __SetPageUptodate(new_page); @@ -2325,7 +2361,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, page_add_anon_rmap(page, vma, address); swap_free(entry); - if (vm_swap_full()) + if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page)) remove_exclusive_swap_page(page); unlock_page(page); @@ -2465,6 +2501,12 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, ret = VM_FAULT_OOM; goto out; } + /* + * Don't let another task, with possibly unlocked vma, + * keep the mlocked page. + */ + if (vma->vm_flags & VM_LOCKED) + clear_page_mlock(vmf.page); copy_user_highpage(page, vmf.page, address, vma); __SetPageUptodate(page); } else { diff --git a/mm/migrate.c b/mm/migrate.c index b10237d8b45..6802a7a3dfe 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -371,6 +371,8 @@ static void migrate_page_copy(struct page *newpage, struct page *page) __set_page_dirty_nobuffers(newpage); } + mlock_migrate_page(newpage, page); + #ifdef CONFIG_SWAP ClearPageSwapCache(page); #endif diff --git a/mm/mlock.c b/mm/mlock.c index 01fbe93eff5..8746fe3f973 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -8,10 +8,18 @@ #include #include #include +#include +#include +#include #include #include #include #include +#include +#include +#include + +#include "internal.h" int can_do_mlock(void) { @@ -23,17 +31,360 @@ int can_do_mlock(void) } EXPORT_SYMBOL(can_do_mlock); +#ifdef CONFIG_UNEVICTABLE_LRU +/* + * Mlocked pages are marked with PageMlocked() flag for efficient testing + * in vmscan and, possibly, the fault path; and to support semi-accurate + * statistics. + * + * An mlocked page [PageMlocked(page)] is unevictable. As such, it will + * be placed on the LRU "unevictable" list, rather than the [in]active lists. + * The unevictable list is an LRU sibling list to the [in]active lists. + * PageUnevictable is set to indicate the unevictable state. + * + * When lazy mlocking via vmscan, it is important to ensure that the + * vma's VM_LOCKED status is not concurrently being modified, otherwise we + * may have mlocked a page that is being munlocked. So lazy mlock must take + * the mmap_sem for read, and verify that the vma really is locked + * (see mm/rmap.c). + */ + +/* + * LRU accounting for clear_page_mlock() + */ +void __clear_page_mlock(struct page *page) +{ + VM_BUG_ON(!PageLocked(page)); + + if (!page->mapping) { /* truncated ? */ + return; + } + + if (!isolate_lru_page(page)) { + putback_lru_page(page); + } else { + /* + * Page not on the LRU yet. Flush all pagevecs and retry. + */ + lru_add_drain_all(); + if (!isolate_lru_page(page)) + putback_lru_page(page); + } +} + +/* + * Mark page as mlocked if not already. + * If page on LRU, isolate and putback to move to unevictable list. + */ +void mlock_vma_page(struct page *page) +{ + BUG_ON(!PageLocked(page)); + + if (!TestSetPageMlocked(page) && !isolate_lru_page(page)) + putback_lru_page(page); +} + +/* + * called from munlock()/munmap() path with page supposedly on the LRU. + * + * Note: unlike mlock_vma_page(), we can't just clear the PageMlocked + * [in try_to_munlock()] and then attempt to isolate the page. We must + * isolate the page to keep others from messing with its unevictable + * and mlocked state while trying to munlock. However, we pre-clear the + * mlocked state anyway as we might lose the isolation race and we might + * not get another chance to clear PageMlocked. If we successfully + * isolate the page and try_to_munlock() detects other VM_LOCKED vmas + * mapping the page, it will restore the PageMlocked state, unless the page + * is mapped in a non-linear vma. So, we go ahead and SetPageMlocked(), + * perhaps redundantly. + * If we lose the isolation race, and the page is mapped by other VM_LOCKED + * vmas, we'll detect this in vmscan--via try_to_munlock() or try_to_unmap() + * either of which will restore the PageMlocked state by calling + * mlock_vma_page() above, if it can grab the vma's mmap sem. + */ +static void munlock_vma_page(struct page *page) +{ + BUG_ON(!PageLocked(page)); + + if (TestClearPageMlocked(page) && !isolate_lru_page(page)) { + try_to_munlock(page); + putback_lru_page(page); + } +} + +/* + * mlock a range of pages in the vma. + * + * This takes care of making the pages present too. + * + * vma->vm_mm->mmap_sem must be held for write. + */ +static int __mlock_vma_pages_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end) +{ + struct mm_struct *mm = vma->vm_mm; + unsigned long addr = start; + struct page *pages[16]; /* 16 gives a reasonable batch */ + int write = !!(vma->vm_flags & VM_WRITE); + int nr_pages = (end - start) / PAGE_SIZE; + int ret; + + VM_BUG_ON(start & ~PAGE_MASK || end & ~PAGE_MASK); + VM_BUG_ON(start < vma->vm_start || end > vma->vm_end); + VM_BUG_ON(!rwsem_is_locked(&vma->vm_mm->mmap_sem)); + + lru_add_drain_all(); /* push cached pages to LRU */ + + while (nr_pages > 0) { + int i; + + cond_resched(); + + /* + * get_user_pages makes pages present if we are + * setting mlock. and this extra reference count will + * disable migration of this page. However, page may + * still be truncated out from under us. + */ + ret = get_user_pages(current, mm, addr, + min_t(int, nr_pages, ARRAY_SIZE(pages)), + write, 0, pages, NULL); + /* + * This can happen for, e.g., VM_NONLINEAR regions before + * a page has been allocated and mapped at a given offset, + * or for addresses that map beyond end of a file. + * We'll mlock the the pages if/when they get faulted in. + */ + if (ret < 0) + break; + if (ret == 0) { + /* + * We know the vma is there, so the only time + * we cannot get a single page should be an + * error (ret < 0) case. + */ + WARN_ON(1); + break; + } + + lru_add_drain(); /* push cached pages to LRU */ + + for (i = 0; i < ret; i++) { + struct page *page = pages[i]; + + lock_page(page); + /* + * Because we lock page here and migration is blocked + * by the elevated reference, we need only check for + * page truncation (file-cache only). + */ + if (page->mapping) + mlock_vma_page(page); + unlock_page(page); + put_page(page); /* ref from get_user_pages() */ + + /* + * here we assume that get_user_pages() has given us + * a list of virtually contiguous pages. + */ + addr += PAGE_SIZE; /* for next get_user_pages() */ + nr_pages--; + } + } + + lru_add_drain_all(); /* to update stats */ + + return 0; /* count entire vma as locked_vm */ +} + +/* + * private structure for munlock page table walk + */ +struct munlock_page_walk { + struct vm_area_struct *vma; + pmd_t *pmd; /* for migration_entry_wait() */ +}; + +/* + * munlock normal pages for present ptes + */ +static int __munlock_pte_handler(pte_t *ptep, unsigned long addr, + unsigned long end, struct mm_walk *walk) +{ + struct munlock_page_walk *mpw = walk->private; + swp_entry_t entry; + struct page *page; + pte_t pte; + +retry: + pte = *ptep; + /* + * If it's a swap pte, we might be racing with page migration. + */ + if (unlikely(!pte_present(pte))) { + if (!is_swap_pte(pte)) + goto out; + entry = pte_to_swp_entry(pte); + if (is_migration_entry(entry)) { + migration_entry_wait(mpw->vma->vm_mm, mpw->pmd, addr); + goto retry; + } + goto out; + } + + page = vm_normal_page(mpw->vma, addr, pte); + if (!page) + goto out; + + lock_page(page); + if (!page->mapping) { + unlock_page(page); + goto retry; + } + munlock_vma_page(page); + unlock_page(page); + +out: + return 0; +} + +/* + * Save pmd for pte handler for waiting on migration entries + */ +static int __munlock_pmd_handler(pmd_t *pmd, unsigned long addr, + unsigned long end, struct mm_walk *walk) +{ + struct munlock_page_walk *mpw = walk->private; + + mpw->pmd = pmd; + return 0; +} + + +/* + * munlock a range of pages in the vma using standard page table walk. + * + * vma->vm_mm->mmap_sem must be held for write. + */ +static void __munlock_vma_pages_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end) +{ + struct mm_struct *mm = vma->vm_mm; + struct munlock_page_walk mpw = { + .vma = vma, + }; + struct mm_walk munlock_page_walk = { + .pmd_entry = __munlock_pmd_handler, + .pte_entry = __munlock_pte_handler, + .private = &mpw, + .mm = mm, + }; + + VM_BUG_ON(start & ~PAGE_MASK || end & ~PAGE_MASK); + VM_BUG_ON(!rwsem_is_locked(&vma->vm_mm->mmap_sem)); + VM_BUG_ON(start < vma->vm_start); + VM_BUG_ON(end > vma->vm_end); + + lru_add_drain_all(); /* push cached pages to LRU */ + walk_page_range(start, end, &munlock_page_walk); + lru_add_drain_all(); /* to update stats */ +} + +#else /* CONFIG_UNEVICTABLE_LRU */ + +/* + * Just make pages present if VM_LOCKED. No-op if unlocking. + */ +static int __mlock_vma_pages_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end) +{ + if (vma->vm_flags & VM_LOCKED) + make_pages_present(start, end); + return 0; +} + +/* + * munlock a range of pages in the vma -- no-op. + */ +static void __munlock_vma_pages_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end) +{ +} +#endif /* CONFIG_UNEVICTABLE_LRU */ + +/* + * mlock all pages in this vma range. For mmap()/mremap()/... + */ +int mlock_vma_pages_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end) +{ + int nr_pages = (end - start) / PAGE_SIZE; + BUG_ON(!(vma->vm_flags & VM_LOCKED)); + + /* + * filter unlockable vmas + */ + if (vma->vm_flags & (VM_IO | VM_PFNMAP)) + goto no_mlock; + + if (!((vma->vm_flags & (VM_DONTEXPAND | VM_RESERVED)) || + is_vm_hugetlb_page(vma) || + vma == get_gate_vma(current))) + return __mlock_vma_pages_range(vma, start, end); + + /* + * User mapped kernel pages or huge pages: + * make these pages present to populate the ptes, but + * fall thru' to reset VM_LOCKED--no need to unlock, and + * return nr_pages so these don't get counted against task's + * locked limit. huge pages are already counted against + * locked vm limit. + */ + make_pages_present(start, end); + +no_mlock: + vma->vm_flags &= ~VM_LOCKED; /* and don't come back! */ + return nr_pages; /* pages NOT mlocked */ +} + + +/* + * munlock all pages in vma. For munmap() and exit(). + */ +void munlock_vma_pages_all(struct vm_area_struct *vma) +{ + vma->vm_flags &= ~VM_LOCKED; + __munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end); +} + +/* + * mlock_fixup - handle mlock[all]/munlock[all] requests. + * + * Filters out "special" vmas -- VM_LOCKED never gets set for these, and + * munlock is a no-op. However, for some special vmas, we go ahead and + * populate the ptes via make_pages_present(). + * + * For vmas that pass the filters, merge/split as appropriate. + */ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev, unsigned long start, unsigned long end, unsigned int newflags) { - struct mm_struct * mm = vma->vm_mm; + struct mm_struct *mm = vma->vm_mm; pgoff_t pgoff; - int pages; + int nr_pages; int ret = 0; - - if (newflags == vma->vm_flags) { - *prev = vma; - goto out; + int lock = newflags & VM_LOCKED; + + if (newflags == vma->vm_flags || + (vma->vm_flags & (VM_IO | VM_PFNMAP))) + goto out; /* don't set VM_LOCKED, don't count */ + + if ((vma->vm_flags & (VM_DONTEXPAND | VM_RESERVED)) || + is_vm_hugetlb_page(vma) || + vma == get_gate_vma(current)) { + if (lock) + make_pages_present(start, end); + goto out; /* don't set VM_LOCKED, don't count */ } pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); @@ -44,8 +395,6 @@ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev, goto success; } - *prev = vma; - if (start != vma->vm_start) { ret = split_vma(mm, vma, start, 1); if (ret) @@ -59,25 +408,32 @@ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev, } success: + /* + * Keep track of amount of locked VM. + */ + nr_pages = (end - start) >> PAGE_SHIFT; + if (!lock) + nr_pages = -nr_pages; + mm->locked_vm += nr_pages; + /* * vm_flags is protected by the mmap_sem held in write mode. * It's okay if try_to_unmap_one unmaps a page just after we - * set VM_LOCKED, make_pages_present below will bring it back. + * set VM_LOCKED, __mlock_vma_pages_range will bring it back. */ vma->vm_flags = newflags; - /* - * Keep track of amount of locked VM. - */ - pages = (end - start) >> PAGE_SHIFT; - if (newflags & VM_LOCKED) { - pages = -pages; - if (!(newflags & VM_IO)) - ret = make_pages_present(start, end); - } + if (lock) { + ret = __mlock_vma_pages_range(vma, start, end); + if (ret > 0) { + mm->locked_vm -= ret; + ret = 0; + } + } else + __munlock_vma_pages_range(vma, start, end); - mm->locked_vm -= pages; out: + *prev = vma; return ret; } diff --git a/mm/mmap.c b/mm/mmap.c index e7a5a68a9c2..7bdfd2661f1 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -662,8 +662,6 @@ again: remove_next = 1 + (end > next->vm_end); * If the vma has a ->close operation then the driver probably needs to release * per-vma resources, so we don't attempt to merge those. */ -#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP) - static inline int is_mergeable_vma(struct vm_area_struct *vma, struct file *file, unsigned long vm_flags) { diff --git a/mm/nommu.c b/mm/nommu.c index ed75bc962fb..2696b24f2bb 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -34,6 +34,8 @@ #include #include +#include "internal.h" + void *high_memory; struct page *mem_map; unsigned long max_mapnr; @@ -128,20 +130,16 @@ unsigned int kobjsize(const void *objp) return PAGE_SIZE << compound_order(page); } -/* - * get a list of pages in an address range belonging to the specified process - * and indicate the VMA that covers each page - * - this is potentially dodgy as we may end incrementing the page count of a - * slab page or a secondary page from a compound page - * - don't permit access to VMAs that don't support it, such as I/O mappings - */ -int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, - unsigned long start, int len, int write, int force, - struct page **pages, struct vm_area_struct **vmas) +int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, + unsigned long start, int len, int flags, + struct page **pages, struct vm_area_struct **vmas) { struct vm_area_struct *vma; unsigned long vm_flags; int i; + int write = !!(flags & GUP_FLAGS_WRITE); + int force = !!(flags & GUP_FLAGS_FORCE); + int ignore = !!(flags & GUP_FLAGS_IGNORE_VMA_PERMISSIONS); /* calculate required read or write permissions. * - if 'force' is set, we only require the "MAY" flags. @@ -156,7 +154,7 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, /* protect what we can, including chardevs */ if (vma->vm_flags & (VM_IO | VM_PFNMAP) || - !(vm_flags & vma->vm_flags)) + (!ignore && !(vm_flags & vma->vm_flags))) goto finish_or_fault; if (pages) { @@ -174,6 +172,30 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, finish_or_fault: return i ? : -EFAULT; } + + +/* + * get a list of pages in an address range belonging to the specified process + * and indicate the VMA that covers each page + * - this is potentially dodgy as we may end incrementing the page count of a + * slab page or a secondary page from a compound page + * - don't permit access to VMAs that don't support it, such as I/O mappings + */ +int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, + unsigned long start, int len, int write, int force, + struct page **pages, struct vm_area_struct **vmas) +{ + int flags = 0; + + if (write) + flags |= GUP_FLAGS_WRITE; + if (force) + flags |= GUP_FLAGS_FORCE; + + return __get_user_pages(tsk, mm, + start, len, flags, + pages, vmas); +} EXPORT_SYMBOL(get_user_pages); DEFINE_RWLOCK(vmlist_lock); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 4125230a1b2..5886586fde6 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -616,7 +616,11 @@ static int prep_new_page(struct page *page, int order, gfp_t gfp_flags) page->flags &= ~(1 << PG_uptodate | 1 << PG_error | 1 << PG_reclaim | 1 << PG_referenced | 1 << PG_arch_1 | - 1 << PG_owner_priv_1 | 1 << PG_mappedtodisk); + 1 << PG_owner_priv_1 | 1 << PG_mappedtodisk +#ifdef CONFIG_UNEVICTABLE_LRU + | 1 << PG_mlocked +#endif + ); set_page_private(page, 0); set_page_refcounted(page); diff --git a/mm/rmap.c b/mm/rmap.c index e8d639b16c6..7e60df99018 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -53,6 +53,8 @@ #include +#include "internal.h" + struct kmem_cache *anon_vma_cachep; /** @@ -290,6 +292,32 @@ pte_t *page_check_address(struct page *page, struct mm_struct *mm, return NULL; } +/** + * page_mapped_in_vma - check whether a page is really mapped in a VMA + * @page: the page to test + * @vma: the VMA to test + * + * Returns 1 if the page is mapped into the page tables of the VMA, 0 + * if the page is not mapped into the page tables of this VMA. Only + * valid for normal file or anonymous VMAs. + */ +static int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma) +{ + unsigned long address; + pte_t *pte; + spinlock_t *ptl; + + address = vma_address(page, vma); + if (address == -EFAULT) /* out of vma range */ + return 0; + pte = page_check_address(page, vma->vm_mm, address, &ptl, 1); + if (!pte) /* the page is not in this mm */ + return 0; + pte_unmap_unlock(pte, ptl); + + return 1; +} + /* * Subfunctions of page_referenced: page_referenced_one called * repeatedly from either page_referenced_anon or page_referenced_file. @@ -311,10 +339,17 @@ static int page_referenced_one(struct page *page, if (!pte) goto out; + /* + * Don't want to elevate referenced for mlocked page that gets this far, + * in order that it progresses to try_to_unmap and is moved to the + * unevictable list. + */ if (vma->vm_flags & VM_LOCKED) { - referenced++; *mapcount = 1; /* break early from loop */ - } else if (ptep_clear_flush_young_notify(vma, address, pte)) + goto out_unmap; + } + + if (ptep_clear_flush_young_notify(vma, address, pte)) referenced++; /* Pretend the page is referenced if the task has the @@ -323,6 +358,7 @@ static int page_referenced_one(struct page *page, rwsem_is_locked(&mm->mmap_sem)) referenced++; +out_unmap: (*mapcount)--; pte_unmap_unlock(pte, ptl); out: @@ -412,11 +448,6 @@ static int page_referenced_file(struct page *page, */ if (mem_cont && !mm_match_cgroup(vma->vm_mm, mem_cont)) continue; - if ((vma->vm_flags & (VM_LOCKED|VM_MAYSHARE)) - == (VM_LOCKED|VM_MAYSHARE)) { - referenced++; - break; - } referenced += page_referenced_one(page, vma, &mapcount); if (!mapcount) break; @@ -739,11 +770,16 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, * If it's recently referenced (perhaps page_referenced * skipped over this mm) then we should reactivate it. */ - if (!migration && ((vma->vm_flags & VM_LOCKED) || - (ptep_clear_flush_young_notify(vma, address, pte)))) { - ret = SWAP_FAIL; - goto out_unmap; - } + if (!migration) { + if (vma->vm_flags & VM_LOCKED) { + ret = SWAP_MLOCK; + goto out_unmap; + } + if (ptep_clear_flush_young_notify(vma, address, pte)) { + ret = SWAP_FAIL; + goto out_unmap; + } + } /* Nuke the page table entry. */ flush_cache_page(vma, address, page_to_pfn(page)); @@ -824,12 +860,17 @@ out: * For very sparsely populated VMAs this is a little inefficient - chances are * there there won't be many ptes located within the scan cluster. In this case * maybe we could scan further - to the end of the pte page, perhaps. + * + * Mlocked pages: check VM_LOCKED under mmap_sem held for read, if we can + * acquire it without blocking. If vma locked, mlock the pages in the cluster, + * rather than unmapping them. If we encounter the "check_page" that vmscan is + * trying to unmap, return SWAP_MLOCK, else default SWAP_AGAIN. */ #define CLUSTER_SIZE min(32*PAGE_SIZE, PMD_SIZE) #define CLUSTER_MASK (~(CLUSTER_SIZE - 1)) -static void try_to_unmap_cluster(unsigned long cursor, - unsigned int *mapcount, struct vm_area_struct *vma) +static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount, + struct vm_area_struct *vma, struct page *check_page) { struct mm_struct *mm = vma->vm_mm; pgd_t *pgd; @@ -841,6 +882,8 @@ static void try_to_unmap_cluster(unsigned long cursor, struct page *page; unsigned long address; unsigned long end; + int ret = SWAP_AGAIN; + int locked_vma = 0; address = (vma->vm_start + cursor) & CLUSTER_MASK; end = address + CLUSTER_SIZE; @@ -851,15 +894,26 @@ static void try_to_unmap_cluster(unsigned long cursor, pgd = pgd_offset(mm, address); if (!pgd_present(*pgd)) - return; + return ret; pud = pud_offset(pgd, address); if (!pud_present(*pud)) - return; + return ret; pmd = pmd_offset(pud, address); if (!pmd_present(*pmd)) - return; + return ret; + + /* + * MLOCK_PAGES => feature is configured. + * if we can acquire the mmap_sem for read, and vma is VM_LOCKED, + * keep the sem while scanning the cluster for mlocking pages. + */ + if (MLOCK_PAGES && down_read_trylock(&vma->vm_mm->mmap_sem)) { + locked_vma = (vma->vm_flags & VM_LOCKED); + if (!locked_vma) + up_read(&vma->vm_mm->mmap_sem); /* don't need it */ + } pte = pte_offset_map_lock(mm, pmd, address, &ptl); @@ -872,6 +926,13 @@ static void try_to_unmap_cluster(unsigned long cursor, page = vm_normal_page(vma, address, *pte); BUG_ON(!page || PageAnon(page)); + if (locked_vma) { + mlock_vma_page(page); /* no-op if already mlocked */ + if (page == check_page) + ret = SWAP_MLOCK; + continue; /* don't unmap */ + } + if (ptep_clear_flush_young_notify(vma, address, pte)) continue; @@ -893,39 +954,104 @@ static void try_to_unmap_cluster(unsigned long cursor, (*mapcount)--; } pte_unmap_unlock(pte - 1, ptl); + if (locked_vma) + up_read(&vma->vm_mm->mmap_sem); + return ret; } -static int try_to_unmap_anon(struct page *page, int migration) +/* + * common handling for pages mapped in VM_LOCKED vmas + */ +static int try_to_mlock_page(struct page *page, struct vm_area_struct *vma) +{ + int mlocked = 0; + + if (down_read_trylock(&vma->vm_mm->mmap_sem)) { + if (vma->vm_flags & VM_LOCKED) { + mlock_vma_page(page); + mlocked++; /* really mlocked the page */ + } + up_read(&vma->vm_mm->mmap_sem); + } + return mlocked; +} + +/** + * try_to_unmap_anon - unmap or unlock anonymous page using the object-based + * rmap method + * @page: the page to unmap/unlock + * @unlock: request for unlock rather than unmap [unlikely] + * @migration: unmapping for migration - ignored if @unlock + * + * Find all the mappings of a page using the mapping pointer and the vma chains + * contained in the anon_vma struct it points to. + * + * This function is only called from try_to_unmap/try_to_munlock for + * anonymous pages. + * When called from try_to_munlock(), the mmap_sem of the mm containing the vma + * where the page was found will be held for write. So, we won't recheck + * vm_flags for that VMA. That should be OK, because that vma shouldn't be + * 'LOCKED. + */ +static int try_to_unmap_anon(struct page *page, int unlock, int migration) { struct anon_vma *anon_vma; struct vm_area_struct *vma; + unsigned int mlocked = 0; int ret = SWAP_AGAIN; + if (MLOCK_PAGES && unlikely(unlock)) + ret = SWAP_SUCCESS; /* default for try_to_munlock() */ + anon_vma = page_lock_anon_vma(page); if (!anon_vma) return ret; list_for_each_entry(vma, &anon_vma->head, anon_vma_node) { - ret = try_to_unmap_one(page, vma, migration); - if (ret == SWAP_FAIL || !page_mapped(page)) - break; + if (MLOCK_PAGES && unlikely(unlock)) { + if (!((vma->vm_flags & VM_LOCKED) && + page_mapped_in_vma(page, vma))) + continue; /* must visit all unlocked vmas */ + ret = SWAP_MLOCK; /* saw at least one mlocked vma */ + } else { + ret = try_to_unmap_one(page, vma, migration); + if (ret == SWAP_FAIL || !page_mapped(page)) + break; + } + if (ret == SWAP_MLOCK) { + mlocked = try_to_mlock_page(page, vma); + if (mlocked) + break; /* stop if actually mlocked page */ + } } page_unlock_anon_vma(anon_vma); + + if (mlocked) + ret = SWAP_MLOCK; /* actually mlocked the page */ + else if (ret == SWAP_MLOCK) + ret = SWAP_AGAIN; /* saw VM_LOCKED vma */ + return ret; } /** - * try_to_unmap_file - unmap file page using the object-based rmap method - * @page: the page to unmap - * @migration: migration flag + * try_to_unmap_file - unmap/unlock file page using the object-based rmap method + * @page: the page to unmap/unlock + * @unlock: request for unlock rather than unmap [unlikely] + * @migration: unmapping for migration - ignored if @unlock * * Find all the mappings of a page using the mapping pointer and the vma chains * contained in the address_space struct it points to. * - * This function is only called from try_to_unmap for object-based pages. + * This function is only called from try_to_unmap/try_to_munlock for + * object-based pages. + * When called from try_to_munlock(), the mmap_sem of the mm containing the vma + * where the page was found will be held for write. So, we won't recheck + * vm_flags for that VMA. That should be OK, because that vma shouldn't be + * 'LOCKED. */ -static int try_to_unmap_file(struct page *page, int migration) +static int try_to_unmap_file(struct page *page, int unlock, int migration) { struct address_space *mapping = page->mapping; pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); @@ -936,20 +1062,44 @@ static int try_to_unmap_file(struct page *page, int migration) unsigned long max_nl_cursor = 0; unsigned long max_nl_size = 0; unsigned int mapcount; + unsigned int mlocked = 0; + + if (MLOCK_PAGES && unlikely(unlock)) + ret = SWAP_SUCCESS; /* default for try_to_munlock() */ spin_lock(&mapping->i_mmap_lock); vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { - ret = try_to_unmap_one(page, vma, migration); - if (ret == SWAP_FAIL || !page_mapped(page)) - goto out; + if (MLOCK_PAGES && unlikely(unlock)) { + if (!(vma->vm_flags & VM_LOCKED)) + continue; /* must visit all vmas */ + ret = SWAP_MLOCK; + } else { + ret = try_to_unmap_one(page, vma, migration); + if (ret == SWAP_FAIL || !page_mapped(page)) + goto out; + } + if (ret == SWAP_MLOCK) { + mlocked = try_to_mlock_page(page, vma); + if (mlocked) + break; /* stop if actually mlocked page */ + } } + if (mlocked) + goto out; + if (list_empty(&mapping->i_mmap_nonlinear)) goto out; list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) { - if ((vma->vm_flags & VM_LOCKED) && !migration) + if (MLOCK_PAGES && unlikely(unlock)) { + if (!(vma->vm_flags & VM_LOCKED)) + continue; /* must visit all vmas */ + ret = SWAP_MLOCK; /* leave mlocked == 0 */ + goto out; /* no need to look further */ + } + if (!MLOCK_PAGES && !migration && (vma->vm_flags & VM_LOCKED)) continue; cursor = (unsigned long) vma->vm_private_data; if (cursor > max_nl_cursor) @@ -959,7 +1109,7 @@ static int try_to_unmap_file(struct page *page, int migration) max_nl_size = cursor; } - if (max_nl_size == 0) { /* any nonlinears locked or reserved */ + if (max_nl_size == 0) { /* all nonlinears locked or reserved ? */ ret = SWAP_FAIL; goto out; } @@ -983,12 +1133,16 @@ static int try_to_unmap_file(struct page *page, int migration) do { list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) { - if ((vma->vm_flags & VM_LOCKED) && !migration) + if (!MLOCK_PAGES && !migration && + (vma->vm_flags & VM_LOCKED)) continue; cursor = (unsigned long) vma->vm_private_data; while ( cursor < max_nl_cursor && cursor < vma->vm_end - vma->vm_start) { - try_to_unmap_cluster(cursor, &mapcount, vma); + ret = try_to_unmap_cluster(cursor, &mapcount, + vma, page); + if (ret == SWAP_MLOCK) + mlocked = 2; /* to return below */ cursor += CLUSTER_SIZE; vma->vm_private_data = (void *) cursor; if ((int)mapcount <= 0) @@ -1009,6 +1163,10 @@ static int try_to_unmap_file(struct page *page, int migration) vma->vm_private_data = NULL; out: spin_unlock(&mapping->i_mmap_lock); + if (mlocked) + ret = SWAP_MLOCK; /* actually mlocked the page */ + else if (ret == SWAP_MLOCK) + ret = SWAP_AGAIN; /* saw VM_LOCKED vma */ return ret; } @@ -1024,6 +1182,7 @@ out: * SWAP_SUCCESS - we succeeded in removing all mappings * SWAP_AGAIN - we missed a mapping, try again later * SWAP_FAIL - the page is unswappable + * SWAP_MLOCK - page is mlocked. */ int try_to_unmap(struct page *page, int migration) { @@ -1032,12 +1191,36 @@ int try_to_unmap(struct page *page, int migration) BUG_ON(!PageLocked(page)); if (PageAnon(page)) - ret = try_to_unmap_anon(page, migration); + ret = try_to_unmap_anon(page, 0, migration); else - ret = try_to_unmap_file(page, migration); - - if (!page_mapped(page)) + ret = try_to_unmap_file(page, 0, migration); + if (ret != SWAP_MLOCK && !page_mapped(page)) ret = SWAP_SUCCESS; return ret; } +#ifdef CONFIG_UNEVICTABLE_LRU +/** + * try_to_munlock - try to munlock a page + * @page: the page to be munlocked + * + * Called from munlock code. Checks all of the VMAs mapping the page + * to make sure nobody else has this page mlocked. The page will be + * returned with PG_mlocked cleared if no other vmas have it mlocked. + * + * Return values are: + * + * SWAP_SUCCESS - no vma's holding page mlocked. + * SWAP_AGAIN - page mapped in mlocked vma -- couldn't acquire mmap sem + * SWAP_MLOCK - page is now mlocked. + */ +int try_to_munlock(struct page *page) +{ + VM_BUG_ON(!PageLocked(page) || PageLRU(page)); + + if (PageAnon(page)) + return try_to_unmap_anon(page, 1, 0); + else + return try_to_unmap_file(page, 1, 0); +} +#endif diff --git a/mm/swap.c b/mm/swap.c index fee6b973f14..bc58c1369dd 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -278,7 +278,7 @@ void lru_add_drain(void) put_cpu(); } -#ifdef CONFIG_NUMA +#if defined(CONFIG_NUMA) || defined(CONFIG_UNEVICTABLE_LRU) static void lru_add_drain_per_cpu(struct work_struct *dummy) { lru_add_drain(); diff --git a/mm/vmscan.c b/mm/vmscan.c index dfb342e0db9..e5aaaad159e 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -582,11 +582,8 @@ static unsigned long shrink_page_list(struct list_head *page_list, sc->nr_scanned++; - if (unlikely(!page_evictable(page, NULL))) { - unlock_page(page); - putback_lru_page(page); - continue; - } + if (unlikely(!page_evictable(page, NULL))) + goto cull_mlocked; if (!sc->may_swap && page_mapped(page)) goto keep_locked; @@ -624,9 +621,19 @@ static unsigned long shrink_page_list(struct list_head *page_list, * Anonymous process memory has backing store? * Try to allocate it some swap space here. */ - if (PageAnon(page) && !PageSwapCache(page)) + if (PageAnon(page) && !PageSwapCache(page)) { + switch (try_to_munlock(page)) { + case SWAP_FAIL: /* shouldn't happen */ + case SWAP_AGAIN: + goto keep_locked; + case SWAP_MLOCK: + goto cull_mlocked; + case SWAP_SUCCESS: + ; /* fall thru'; add to swap cache */ + } if (!add_to_swap(page, GFP_ATOMIC)) goto activate_locked; + } #endif /* CONFIG_SWAP */ mapping = page_mapping(page); @@ -641,6 +648,8 @@ static unsigned long shrink_page_list(struct list_head *page_list, goto activate_locked; case SWAP_AGAIN: goto keep_locked; + case SWAP_MLOCK: + goto cull_mlocked; case SWAP_SUCCESS: ; /* try to free the page below */ } @@ -731,6 +740,11 @@ free_it: } continue; +cull_mlocked: + unlock_page(page); + putback_lru_page(page); + continue; + activate_locked: /* Not a candidate for swapping, so reclaim swap space. */ if (PageSwapCache(page) && vm_swap_full()) @@ -742,7 +756,7 @@ keep_locked: unlock_page(page); keep: list_add(&page->lru, &ret_pages); - VM_BUG_ON(PageLRU(page)); + VM_BUG_ON(PageLRU(page) || PageUnevictable(page)); } list_splice(&ret_pages, page_list); if (pagevec_count(&freed_pvec)) @@ -2329,12 +2343,13 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) * @vma: the VMA in which the page is or will be mapped, may be NULL * * Test whether page is evictable--i.e., should be placed on active/inactive - * lists vs unevictable list. + * lists vs unevictable list. The vma argument is !NULL when called from the + * fault path to determine how to instantate a new page. * * Reasons page might not be evictable: * (1) page's mapping marked unevictable + * (2) page is part of an mlocked VMA * - * TODO - later patches */ int page_evictable(struct page *page, struct vm_area_struct *vma) { @@ -2342,7 +2357,8 @@ int page_evictable(struct page *page, struct vm_area_struct *vma) if (mapping_unevictable(page_mapping(page))) return 0; - /* TODO: test page [!]evictable conditions */ + if (PageMlocked(page) || (vma && is_mlocked_vma(vma, page))) + return 0; return 1; } -- cgit v1.2.3-70-g09d2 From ba470de43188cdbff795b5da43a1474523c6c2fb Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Sat, 18 Oct 2008 20:26:50 -0700 Subject: mmap: handle mlocked pages during map, remap, unmap Originally by Nick Piggin Remove mlocked pages from the LRU using "unevictable infrastructure" during mmap(), munmap(), mremap() and truncate(). Try to move back to normal LRU lists on munmap() when last mlocked mapping removed. Remove PageMlocked() status when page truncated from file. [akpm@linux-foundation.org: cleanup] [kamezawa.hiroyu@jp.fujitsu.com: fix double unlock_page()] [kosaki.motohiro@jp.fujitsu.com: split LRU: munlock rework] [lee.schermerhorn@hp.com: mlock: fix __mlock_vma_pages_range comment block] [akpm@linux-foundation.org: remove bogus kerneldoc token] Signed-off-by: Nick Piggin Signed-off-by: Lee Schermerhorn Signed-off-by: Rik van Riel Signed-off-by: KOSAKI Motohiro Signed-off-by: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/fremap.c | 27 +++++-- mm/internal.h | 9 ++- mm/mlock.c | 221 ++++++++++++++++++++++++---------------------------------- mm/mmap.c | 71 ++++++++++++++----- mm/mremap.c | 8 ++- mm/truncate.c | 4 ++ 6 files changed, 180 insertions(+), 160 deletions(-) (limited to 'mm/internal.h') diff --git a/mm/fremap.c b/mm/fremap.c index 7881638e4a1..7d12ca70ef7 100644 --- a/mm/fremap.c +++ b/mm/fremap.c @@ -21,6 +21,8 @@ #include #include +#include "internal.h" + static void zap_pte(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) { @@ -215,15 +217,31 @@ asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size, spin_unlock(&mapping->i_mmap_lock); } + if (vma->vm_flags & VM_LOCKED) { + /* + * drop PG_Mlocked flag for over-mapped range + */ + unsigned int saved_flags = vma->vm_flags; + munlock_vma_pages_range(vma, start, start + size); + vma->vm_flags = saved_flags; + } + mmu_notifier_invalidate_range_start(mm, start, start + size); err = populate_range(mm, vma, start, size, pgoff); mmu_notifier_invalidate_range_end(mm, start, start + size); if (!err && !(flags & MAP_NONBLOCK)) { - if (unlikely(has_write_lock)) { - downgrade_write(&mm->mmap_sem); - has_write_lock = 0; + if (vma->vm_flags & VM_LOCKED) { + /* + * might be mapping previously unmapped range of file + */ + mlock_vma_pages_range(vma, start, start + size); + } else { + if (unlikely(has_write_lock)) { + downgrade_write(&mm->mmap_sem); + has_write_lock = 0; + } + make_pages_present(start, start+size); } - make_pages_present(start, start+size); } /* @@ -240,4 +258,3 @@ out: return err; } - diff --git a/mm/internal.h b/mm/internal.h index 4ebf0bef9a3..48e32f79057 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -61,9 +61,14 @@ static inline unsigned long page_order(struct page *page) return page_private(page); } -extern int mlock_vma_pages_range(struct vm_area_struct *vma, +extern long mlock_vma_pages_range(struct vm_area_struct *vma, unsigned long start, unsigned long end); -extern void munlock_vma_pages_all(struct vm_area_struct *vma); +extern void munlock_vma_pages_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end); +static inline void munlock_vma_pages_all(struct vm_area_struct *vma) +{ + munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end); +} #ifdef CONFIG_UNEVICTABLE_LRU /* diff --git a/mm/mlock.c b/mm/mlock.c index c83896a7250..8b478350a2a 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -112,26 +112,49 @@ static void munlock_vma_page(struct page *page) } } -/* - * mlock a range of pages in the vma. +/** + * __mlock_vma_pages_range() - mlock/munlock a range of pages in the vma. + * @vma: target vma + * @start: start address + * @end: end address + * @mlock: 0 indicate munlock, otherwise mlock. + * + * If @mlock == 0, unlock an mlocked range; + * else mlock the range of pages. This takes care of making the pages present , + * too. * - * This takes care of making the pages present too. + * return 0 on success, negative error code on error. * - * vma->vm_mm->mmap_sem must be held for write. + * vma->vm_mm->mmap_sem must be held for at least read. */ -static int __mlock_vma_pages_range(struct vm_area_struct *vma, - unsigned long start, unsigned long end) +static long __mlock_vma_pages_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end, + int mlock) { struct mm_struct *mm = vma->vm_mm; unsigned long addr = start; struct page *pages[16]; /* 16 gives a reasonable batch */ - int write = !!(vma->vm_flags & VM_WRITE); int nr_pages = (end - start) / PAGE_SIZE; int ret; + int gup_flags = 0; - VM_BUG_ON(start & ~PAGE_MASK || end & ~PAGE_MASK); - VM_BUG_ON(start < vma->vm_start || end > vma->vm_end); - VM_BUG_ON(!rwsem_is_locked(&vma->vm_mm->mmap_sem)); + VM_BUG_ON(start & ~PAGE_MASK); + VM_BUG_ON(end & ~PAGE_MASK); + VM_BUG_ON(start < vma->vm_start); + VM_BUG_ON(end > vma->vm_end); + VM_BUG_ON((!rwsem_is_locked(&mm->mmap_sem)) && + (atomic_read(&mm->mm_users) != 0)); + + /* + * mlock: don't page populate if page has PROT_NONE permission. + * munlock: the pages always do munlock althrough + * its has PROT_NONE permission. + */ + if (!mlock) + gup_flags |= GUP_FLAGS_IGNORE_VMA_PERMISSIONS; + + if (vma->vm_flags & VM_WRITE) + gup_flags |= GUP_FLAGS_WRITE; lru_add_drain_all(); /* push cached pages to LRU */ @@ -146,9 +169,9 @@ static int __mlock_vma_pages_range(struct vm_area_struct *vma, * disable migration of this page. However, page may * still be truncated out from under us. */ - ret = get_user_pages(current, mm, addr, + ret = __get_user_pages(current, mm, addr, min_t(int, nr_pages, ARRAY_SIZE(pages)), - write, 0, pages, NULL); + gup_flags, pages, NULL); /* * This can happen for, e.g., VM_NONLINEAR regions before * a page has been allocated and mapped at a given offset, @@ -178,8 +201,12 @@ static int __mlock_vma_pages_range(struct vm_area_struct *vma, * by the elevated reference, we need only check for * page truncation (file-cache only). */ - if (page->mapping) - mlock_vma_page(page); + if (page->mapping) { + if (mlock) + mlock_vma_page(page); + else + munlock_vma_page(page); + } unlock_page(page); put_page(page); /* ref from get_user_pages() */ @@ -197,125 +224,38 @@ static int __mlock_vma_pages_range(struct vm_area_struct *vma, return 0; /* count entire vma as locked_vm */ } -/* - * private structure for munlock page table walk - */ -struct munlock_page_walk { - struct vm_area_struct *vma; - pmd_t *pmd; /* for migration_entry_wait() */ -}; - -/* - * munlock normal pages for present ptes - */ -static int __munlock_pte_handler(pte_t *ptep, unsigned long addr, - unsigned long end, struct mm_walk *walk) -{ - struct munlock_page_walk *mpw = walk->private; - swp_entry_t entry; - struct page *page; - pte_t pte; - -retry: - pte = *ptep; - /* - * If it's a swap pte, we might be racing with page migration. - */ - if (unlikely(!pte_present(pte))) { - if (!is_swap_pte(pte)) - goto out; - entry = pte_to_swp_entry(pte); - if (is_migration_entry(entry)) { - migration_entry_wait(mpw->vma->vm_mm, mpw->pmd, addr); - goto retry; - } - goto out; - } - - page = vm_normal_page(mpw->vma, addr, pte); - if (!page) - goto out; - - lock_page(page); - if (!page->mapping) { - unlock_page(page); - goto retry; - } - munlock_vma_page(page); - unlock_page(page); - -out: - return 0; -} - -/* - * Save pmd for pte handler for waiting on migration entries - */ -static int __munlock_pmd_handler(pmd_t *pmd, unsigned long addr, - unsigned long end, struct mm_walk *walk) -{ - struct munlock_page_walk *mpw = walk->private; - - mpw->pmd = pmd; - return 0; -} - - -/* - * munlock a range of pages in the vma using standard page table walk. - * - * vma->vm_mm->mmap_sem must be held for write. - */ -static void __munlock_vma_pages_range(struct vm_area_struct *vma, - unsigned long start, unsigned long end) -{ - struct mm_struct *mm = vma->vm_mm; - struct munlock_page_walk mpw = { - .vma = vma, - }; - struct mm_walk munlock_page_walk = { - .pmd_entry = __munlock_pmd_handler, - .pte_entry = __munlock_pte_handler, - .private = &mpw, - .mm = mm, - }; - - VM_BUG_ON(start & ~PAGE_MASK || end & ~PAGE_MASK); - VM_BUG_ON(!rwsem_is_locked(&vma->vm_mm->mmap_sem)); - VM_BUG_ON(start < vma->vm_start); - VM_BUG_ON(end > vma->vm_end); - - lru_add_drain_all(); /* push cached pages to LRU */ - walk_page_range(start, end, &munlock_page_walk); - lru_add_drain_all(); /* to update stats */ -} - #else /* CONFIG_UNEVICTABLE_LRU */ /* * Just make pages present if VM_LOCKED. No-op if unlocking. */ -static int __mlock_vma_pages_range(struct vm_area_struct *vma, - unsigned long start, unsigned long end) +static long __mlock_vma_pages_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end, + int mlock) { - if (vma->vm_flags & VM_LOCKED) + if (mlock && (vma->vm_flags & VM_LOCKED)) make_pages_present(start, end); return 0; } - -/* - * munlock a range of pages in the vma -- no-op. - */ -static void __munlock_vma_pages_range(struct vm_area_struct *vma, - unsigned long start, unsigned long end) -{ -} #endif /* CONFIG_UNEVICTABLE_LRU */ -/* - * mlock all pages in this vma range. For mmap()/mremap()/... +/** + * mlock_vma_pages_range() - mlock pages in specified vma range. + * @vma - the vma containing the specfied address range + * @start - starting address in @vma to mlock + * @end - end address [+1] in @vma to mlock + * + * For mmap()/mremap()/expansion of mlocked vma. + * + * return 0 on success for "normal" vmas. + * + * return number of pages [> 0] to be removed from locked_vm on success + * of "special" vmas. + * + * return negative error if vma spanning @start-@range disappears while + * mmap semaphore is dropped. Unlikely? */ -int mlock_vma_pages_range(struct vm_area_struct *vma, +long mlock_vma_pages_range(struct vm_area_struct *vma, unsigned long start, unsigned long end) { struct mm_struct *mm = vma->vm_mm; @@ -331,8 +271,10 @@ int mlock_vma_pages_range(struct vm_area_struct *vma, if (!((vma->vm_flags & (VM_DONTEXPAND | VM_RESERVED)) || is_vm_hugetlb_page(vma) || vma == get_gate_vma(current))) { + long error; downgrade_write(&mm->mmap_sem); - nr_pages = __mlock_vma_pages_range(vma, start, end); + + error = __mlock_vma_pages_range(vma, start, end, 1); up_read(&mm->mmap_sem); /* vma can change or disappear */ @@ -340,8 +282,9 @@ int mlock_vma_pages_range(struct vm_area_struct *vma, vma = find_vma(mm, start); /* non-NULL vma must contain @start, but need to check @end */ if (!vma || end > vma->vm_end) - return -EAGAIN; - return nr_pages; + return -ENOMEM; + + return 0; /* hide other errors from mmap(), et al */ } /* @@ -356,17 +299,33 @@ int mlock_vma_pages_range(struct vm_area_struct *vma, no_mlock: vma->vm_flags &= ~VM_LOCKED; /* and don't come back! */ - return nr_pages; /* pages NOT mlocked */ + return nr_pages; /* error or pages NOT mlocked */ } /* - * munlock all pages in vma. For munmap() and exit(). + * munlock_vma_pages_range() - munlock all pages in the vma range.' + * @vma - vma containing range to be munlock()ed. + * @start - start address in @vma of the range + * @end - end of range in @vma. + * + * For mremap(), munmap() and exit(). + * + * Called with @vma VM_LOCKED. + * + * Returns with VM_LOCKED cleared. Callers must be prepared to + * deal with this. + * + * We don't save and restore VM_LOCKED here because pages are + * still on lru. In unmap path, pages might be scanned by reclaim + * and re-mlocked by try_to_{munlock|unmap} before we unmap and + * free them. This will result in freeing mlocked pages. */ -void munlock_vma_pages_all(struct vm_area_struct *vma) +void munlock_vma_pages_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end) { vma->vm_flags &= ~VM_LOCKED; - __munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end); + __mlock_vma_pages_range(vma, start, end, 0); } /* @@ -443,7 +402,7 @@ success: */ downgrade_write(&mm->mmap_sem); - ret = __mlock_vma_pages_range(vma, start, end); + ret = __mlock_vma_pages_range(vma, start, end, 1); if (ret > 0) { mm->locked_vm -= ret; ret = 0; @@ -460,7 +419,7 @@ success: *prev = find_vma(mm, start); /* non-NULL *prev must contain @start, but need to check @end */ if (!(*prev) || end > (*prev)->vm_end) - ret = -EAGAIN; + ret = -ENOMEM; } else { /* * TODO: for unlocking, pages will already be resident, so @@ -469,7 +428,7 @@ success: * while. Should we downgrade the semaphore for both lock * AND unlock ? */ - __munlock_vma_pages_range(vma, start, end); + __mlock_vma_pages_range(vma, start, end, 0); } out: diff --git a/mm/mmap.c b/mm/mmap.c index 7bdfd2661f1..505a454f365 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -970,6 +970,7 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, return -EPERM; vm_flags |= VM_LOCKED; } + /* mlock MCL_FUTURE? */ if (vm_flags & VM_LOCKED) { unsigned long locked, lock_limit; @@ -1137,10 +1138,12 @@ munmap_back: * The VM_SHARED test is necessary because shmem_zero_setup * will create the file object for a shared anonymous map below. */ - if (!file && !(vm_flags & VM_SHARED) && - vma_merge(mm, prev, addr, addr + len, vm_flags, - NULL, NULL, pgoff, NULL)) - goto out; + if (!file && !(vm_flags & VM_SHARED)) { + vma = vma_merge(mm, prev, addr, addr + len, vm_flags, + NULL, NULL, pgoff, NULL); + if (vma) + goto out; + } /* * Determine the object being mapped and call the appropriate @@ -1222,10 +1225,14 @@ out: mm->total_vm += len >> PAGE_SHIFT; vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); if (vm_flags & VM_LOCKED) { - mm->locked_vm += len >> PAGE_SHIFT; - make_pages_present(addr, addr + len); - } - if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK)) + /* + * makes pages present; downgrades, drops, reacquires mmap_sem + */ + long nr_pages = mlock_vma_pages_range(vma, addr, addr + len); + if (nr_pages < 0) + return nr_pages; /* vma gone! */ + mm->locked_vm += (len >> PAGE_SHIFT) - nr_pages; + } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK)) make_pages_present(addr, addr + len); return addr; @@ -1698,8 +1705,10 @@ find_extend_vma(struct mm_struct *mm, unsigned long addr) return vma; if (!prev || expand_stack(prev, addr)) return NULL; - if (prev->vm_flags & VM_LOCKED) - make_pages_present(addr, prev->vm_end); + if (prev->vm_flags & VM_LOCKED) { + if (mlock_vma_pages_range(prev, addr, prev->vm_end) < 0) + return NULL; /* vma gone! */ + } return prev; } #else @@ -1725,8 +1734,10 @@ find_extend_vma(struct mm_struct * mm, unsigned long addr) start = vma->vm_start; if (expand_stack(vma, addr)) return NULL; - if (vma->vm_flags & VM_LOCKED) - make_pages_present(addr, start); + if (vma->vm_flags & VM_LOCKED) { + if (mlock_vma_pages_range(vma, addr, start) < 0) + return NULL; /* vma gone! */ + } return vma; } #endif @@ -1745,8 +1756,6 @@ static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) long nrpages = vma_pages(vma); mm->total_vm -= nrpages; - if (vma->vm_flags & VM_LOCKED) - mm->locked_vm -= nrpages; vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages); vma = remove_vma(vma); } while (vma); @@ -1911,6 +1920,20 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) } vma = prev? prev->vm_next: mm->mmap; + /* + * unlock any mlock()ed ranges before detaching vmas + */ + if (mm->locked_vm) { + struct vm_area_struct *tmp = vma; + while (tmp && tmp->vm_start < end) { + if (tmp->vm_flags & VM_LOCKED) { + mm->locked_vm -= vma_pages(tmp); + munlock_vma_pages_all(tmp); + } + tmp = tmp->vm_next; + } + } + /* * Remove the vma's, and unmap the actual pages */ @@ -2023,8 +2046,9 @@ unsigned long do_brk(unsigned long addr, unsigned long len) return -ENOMEM; /* Can we just expand an old private anonymous mapping? */ - if (vma_merge(mm, prev, addr, addr + len, flags, - NULL, NULL, pgoff, NULL)) + vma = vma_merge(mm, prev, addr, addr + len, flags, + NULL, NULL, pgoff, NULL); + if (vma) goto out; /* @@ -2046,8 +2070,8 @@ unsigned long do_brk(unsigned long addr, unsigned long len) out: mm->total_vm += len >> PAGE_SHIFT; if (flags & VM_LOCKED) { - mm->locked_vm += len >> PAGE_SHIFT; - make_pages_present(addr, addr + len); + if (!mlock_vma_pages_range(vma, addr, addr + len)) + mm->locked_vm += (len >> PAGE_SHIFT); } return addr; } @@ -2058,7 +2082,7 @@ EXPORT_SYMBOL(do_brk); void exit_mmap(struct mm_struct *mm) { struct mmu_gather *tlb; - struct vm_area_struct *vma = mm->mmap; + struct vm_area_struct *vma; unsigned long nr_accounted = 0; unsigned long end; @@ -2066,6 +2090,15 @@ void exit_mmap(struct mm_struct *mm) arch_exit_mmap(mm); mmu_notifier_release(mm); + if (mm->locked_vm) { + vma = mm->mmap; + while (vma) { + if (vma->vm_flags & VM_LOCKED) + munlock_vma_pages_all(vma); + vma = vma->vm_next; + } + } + vma = mm->mmap; lru_add_drain(); flush_cache_mm(mm); tlb = tlb_gather_mmu(mm, 1); diff --git a/mm/mremap.c b/mm/mremap.c index 1a7743923c8..58a2908f42f 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -24,6 +24,8 @@ #include #include +#include "internal.h" + static pmd_t *get_old_pmd(struct mm_struct *mm, unsigned long addr) { pgd_t *pgd; @@ -238,8 +240,8 @@ static unsigned long move_vma(struct vm_area_struct *vma, if (vm_flags & VM_LOCKED) { mm->locked_vm += new_len >> PAGE_SHIFT; if (new_len > old_len) - make_pages_present(new_addr + old_len, - new_addr + new_len); + mlock_vma_pages_range(new_vma, new_addr + old_len, + new_addr + new_len); } return new_addr; @@ -379,7 +381,7 @@ unsigned long do_mremap(unsigned long addr, vm_stat_account(mm, vma->vm_flags, vma->vm_file, pages); if (vma->vm_flags & VM_LOCKED) { mm->locked_vm += pages; - make_pages_present(addr + old_len, + mlock_vma_pages_range(vma, addr + old_len, addr + new_len); } ret = addr; diff --git a/mm/truncate.c b/mm/truncate.c index e83e4b114ef..1229211104f 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -18,6 +18,7 @@ #include #include /* grr. try_to_release_page, do_invalidatepage */ +#include "internal.h" /** @@ -103,6 +104,7 @@ truncate_complete_page(struct address_space *mapping, struct page *page) cancel_dirty_page(page, PAGE_CACHE_SIZE); + clear_page_mlock(page); remove_from_page_cache(page); ClearPageMappedToDisk(page); page_cache_release(page); /* pagecache ref */ @@ -127,6 +129,7 @@ invalidate_complete_page(struct address_space *mapping, struct page *page) if (PagePrivate(page) && !try_to_release_page(page, 0)) return 0; + clear_page_mlock(page); ret = remove_mapping(mapping, page); return ret; @@ -352,6 +355,7 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page) if (PageDirty(page)) goto failed; + clear_page_mlock(page); BUG_ON(PagePrivate(page)); __remove_from_page_cache(page); spin_unlock_irq(&mapping->tree_lock); -- cgit v1.2.3-70-g09d2 From 5344b7e648980cc2ca613ec03a56a8222ff48820 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Sat, 18 Oct 2008 20:26:51 -0700 Subject: vmstat: mlocked pages statistics Add NR_MLOCK zone page state, which provides a (conservative) count of mlocked pages (actually, the number of mlocked pages moved off the LRU). Reworked by lts to fit in with the modified mlock page support in the Reclaim Scalability series. [kosaki.motohiro@jp.fujitsu.com: fix incorrect Mlocked field of /proc/meminfo] [lee.schermerhorn@hp.com: mlocked-pages: add event counting with statistics] Signed-off-by: Nick Piggin Signed-off-by: Lee Schermerhorn Signed-off-by: Rik van Riel Signed-off-by: KOSAKI Motohiro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/base/node.c | 4 +++- fs/proc/proc_misc.c | 2 ++ include/linux/mmzone.h | 2 ++ include/linux/vmstat.h | 4 ++++ mm/internal.h | 16 +++++++++++++--- mm/mlock.c | 41 ++++++++++++++++++++++++++++++++++++----- mm/vmstat.c | 5 +++++ 7 files changed, 65 insertions(+), 9 deletions(-) (limited to 'mm/internal.h') diff --git a/drivers/base/node.c b/drivers/base/node.c index 11a9a05cf55..fb45d88a244 100644 --- a/drivers/base/node.c +++ b/drivers/base/node.c @@ -71,7 +71,8 @@ static ssize_t node_read_meminfo(struct sys_device * dev, "Node %d Active(file): %8lu kB\n" "Node %d Inactive(file): %8lu kB\n" #ifdef CONFIG_UNEVICTABLE_LRU - "Node %d Noreclaim: %8lu kB\n" + "Node %d Unevictable: %8lu kB\n" + "Node %d Mlocked: %8lu kB\n" #endif #ifdef CONFIG_HIGHMEM "Node %d HighTotal: %8lu kB\n" @@ -104,6 +105,7 @@ static ssize_t node_read_meminfo(struct sys_device * dev, nid, K(node_page_state(nid, NR_INACTIVE_FILE)), #ifdef CONFIG_UNEVICTABLE_LRU nid, K(node_page_state(nid, NR_UNEVICTABLE)), + nid, K(node_page_state(nid, NR_MLOCK)), #endif #ifdef CONFIG_HIGHMEM nid, K(i.totalhigh), diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c index 6dd60eaea99..61b25f4eabe 100644 --- a/fs/proc/proc_misc.c +++ b/fs/proc/proc_misc.c @@ -176,6 +176,7 @@ static int meminfo_read_proc(char *page, char **start, off_t off, "Inactive(file): %8lu kB\n" #ifdef CONFIG_UNEVICTABLE_LRU "Unevictable: %8lu kB\n" + "Mlocked: %8lu kB\n" #endif #ifdef CONFIG_HIGHMEM "HighTotal: %8lu kB\n" @@ -217,6 +218,7 @@ static int meminfo_read_proc(char *page, char **start, off_t off, K(pages[LRU_INACTIVE_FILE]), #ifdef CONFIG_UNEVICTABLE_LRU K(pages[LRU_UNEVICTABLE]), + K(global_page_state(NR_MLOCK)), #endif #ifdef CONFIG_HIGHMEM K(i.totalhigh), diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index d1f60d5fe2e..da2d053a95f 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -88,8 +88,10 @@ enum zone_stat_item { NR_ACTIVE_FILE, /* " " " " " */ #ifdef CONFIG_UNEVICTABLE_LRU NR_UNEVICTABLE, /* " " " " " */ + NR_MLOCK, /* mlock()ed pages found and moved off LRU */ #else NR_UNEVICTABLE = NR_ACTIVE_FILE, /* avoid compiler errors in dead code */ + NR_MLOCK = NR_ACTIVE_FILE, #endif NR_ANON_PAGES, /* Mapped anonymous pages */ NR_FILE_MAPPED, /* pagecache pages mapped into pagetables. diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h index 135840cd7fe..05b805020be 100644 --- a/include/linux/vmstat.h +++ b/include/linux/vmstat.h @@ -45,6 +45,10 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, UNEVICTABLE_PGCULLED, /* culled to noreclaim list */ UNEVICTABLE_PGSCANNED, /* scanned for reclaimability */ UNEVICTABLE_PGRESCUED, /* rescued from noreclaim list */ + UNEVICTABLE_PGMLOCKED, + UNEVICTABLE_PGMUNLOCKED, + UNEVICTABLE_PGCLEARED, /* on COW, page truncate */ + UNEVICTABLE_PGSTRANDED, /* unable to isolate on unlock */ #endif NR_VM_EVENT_ITEMS }; diff --git a/mm/internal.h b/mm/internal.h index 48e32f79057..1cfbf2e2bc9 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -101,7 +101,10 @@ static inline int is_mlocked_vma(struct vm_area_struct *vma, struct page *page) if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED)) return 0; - SetPageMlocked(page); + if (!TestSetPageMlocked(page)) { + inc_zone_page_state(page, NR_MLOCK); + count_vm_event(UNEVICTABLE_PGMLOCKED); + } return 1; } @@ -128,12 +131,19 @@ static inline void clear_page_mlock(struct page *page) /* * mlock_migrate_page - called only from migrate_page_copy() to - * migrate the Mlocked page flag + * migrate the Mlocked page flag; update statistics. */ static inline void mlock_migrate_page(struct page *newpage, struct page *page) { - if (TestClearPageMlocked(page)) + if (TestClearPageMlocked(page)) { + unsigned long flags; + + local_irq_save(flags); + __dec_zone_page_state(page, NR_MLOCK); SetPageMlocked(newpage); + __inc_zone_page_state(newpage, NR_MLOCK); + local_irq_restore(flags); + } } diff --git a/mm/mlock.c b/mm/mlock.c index 8b478350a2a..bce1b22c36c 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -60,6 +60,8 @@ void __clear_page_mlock(struct page *page) return; } + dec_zone_page_state(page, NR_MLOCK); + count_vm_event(UNEVICTABLE_PGCLEARED); if (!isolate_lru_page(page)) { putback_lru_page(page); } else { @@ -69,6 +71,9 @@ void __clear_page_mlock(struct page *page) lru_add_drain_all(); if (!isolate_lru_page(page)) putback_lru_page(page); + else if (PageUnevictable(page)) + count_vm_event(UNEVICTABLE_PGSTRANDED); + } } @@ -80,8 +85,12 @@ void mlock_vma_page(struct page *page) { BUG_ON(!PageLocked(page)); - if (!TestSetPageMlocked(page) && !isolate_lru_page(page)) - putback_lru_page(page); + if (!TestSetPageMlocked(page)) { + inc_zone_page_state(page, NR_MLOCK); + count_vm_event(UNEVICTABLE_PGMLOCKED); + if (!isolate_lru_page(page)) + putback_lru_page(page); + } } /* @@ -106,9 +115,31 @@ static void munlock_vma_page(struct page *page) { BUG_ON(!PageLocked(page)); - if (TestClearPageMlocked(page) && !isolate_lru_page(page)) { - try_to_munlock(page); - putback_lru_page(page); + if (TestClearPageMlocked(page)) { + dec_zone_page_state(page, NR_MLOCK); + if (!isolate_lru_page(page)) { + int ret = try_to_munlock(page); + /* + * did try_to_unlock() succeed or punt? + */ + if (ret == SWAP_SUCCESS || ret == SWAP_AGAIN) + count_vm_event(UNEVICTABLE_PGMUNLOCKED); + + putback_lru_page(page); + } else { + /* + * We lost the race. let try_to_unmap() deal + * with it. At least we get the page state and + * mlock stats right. However, page is still on + * the noreclaim list. We'll fix that up when + * the page is eventually freed or we scan the + * noreclaim list. + */ + if (PageUnevictable(page)) + count_vm_event(UNEVICTABLE_PGSTRANDED); + else + count_vm_event(UNEVICTABLE_PGMUNLOCKED); + } } } diff --git a/mm/vmstat.c b/mm/vmstat.c index 6db2f631931..9e28abc0a0b 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -625,6 +625,7 @@ static const char * const vmstat_text[] = { "nr_active_file", #ifdef CONFIG_UNEVICTABLE_LRU "nr_unevictable", + "nr_mlock", #endif "nr_anon_pages", "nr_mapped", @@ -684,6 +685,10 @@ static const char * const vmstat_text[] = { "unevictable_pgs_culled", "unevictable_pgs_scanned", "unevictable_pgs_rescued", + "unevictable_pgs_mlocked", + "unevictable_pgs_munlocked", + "unevictable_pgs_cleared", + "unevictable_pgs_stranded", #endif #endif }; -- cgit v1.2.3-70-g09d2 From 985737cf2ea096ea946aed82c7484d40defc71a8 Mon Sep 17 00:00:00 2001 From: Lee Schermerhorn Date: Sat, 18 Oct 2008 20:26:53 -0700 Subject: mlock: count attempts to free mlocked page Allow free of mlock()ed pages. This shouldn't happen, but during developement, it occasionally did. This patch allows us to survive that condition, while keeping the statistics and events correct for debug. Signed-off-by: Lee Schermerhorn Signed-off-by: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/vmstat.h | 1 + mm/internal.h | 17 +++++++++++++++++ mm/page_alloc.c | 1 + mm/vmstat.c | 1 + 4 files changed, 20 insertions(+) (limited to 'mm/internal.h') diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h index 05b805020be..9cd3ab0f554 100644 --- a/include/linux/vmstat.h +++ b/include/linux/vmstat.h @@ -49,6 +49,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, UNEVICTABLE_PGMUNLOCKED, UNEVICTABLE_PGCLEARED, /* on COW, page truncate */ UNEVICTABLE_PGSTRANDED, /* unable to isolate on unlock */ + UNEVICTABLE_MLOCKFREED, #endif NR_VM_EVENT_ITEMS }; diff --git a/mm/internal.h b/mm/internal.h index 1cfbf2e2bc9..e4e728bdf32 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -146,6 +146,22 @@ static inline void mlock_migrate_page(struct page *newpage, struct page *page) } } +/* + * free_page_mlock() -- clean up attempts to free and mlocked() page. + * Page should not be on lru, so no need to fix that up. + * free_pages_check() will verify... + */ +static inline void free_page_mlock(struct page *page) +{ + if (unlikely(TestClearPageMlocked(page))) { + unsigned long flags; + + local_irq_save(flags); + __dec_zone_page_state(page, NR_MLOCK); + __count_vm_event(UNEVICTABLE_MLOCKFREED); + local_irq_restore(flags); + } +} #else /* CONFIG_UNEVICTABLE_LRU */ static inline int is_mlocked_vma(struct vm_area_struct *v, struct page *p) @@ -155,6 +171,7 @@ static inline int is_mlocked_vma(struct vm_area_struct *v, struct page *p) static inline void clear_page_mlock(struct page *page) { } static inline void mlock_vma_page(struct page *page) { } static inline void mlock_migrate_page(struct page *new, struct page *old) { } +static inline void free_page_mlock(struct page *page) { } #endif /* CONFIG_UNEVICTABLE_LRU */ diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 5886586fde6..cfbadad75d1 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -454,6 +454,7 @@ static inline void __free_one_page(struct page *page, static inline int free_pages_check(struct page *page) { + free_page_mlock(page); if (unlikely(page_mapcount(page) | (page->mapping != NULL) | (page_get_page_cgroup(page) != NULL) | diff --git a/mm/vmstat.c b/mm/vmstat.c index 9e28abc0a0b..9343227c5c6 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -689,6 +689,7 @@ static const char * const vmstat_text[] = { "unevictable_pgs_munlocked", "unevictable_pgs_cleared", "unevictable_pgs_stranded", + "unevictable_pgs_mlockfreed", #endif #endif }; -- cgit v1.2.3-70-g09d2