X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=mm%2Fvmscan.c;h=3ff3311447f58c2122a5154a85b6cd034d6c7e0e;hb=d79df0b1eda0099a22cbcece01ce5e7d222450de;hp=79a98d98ed33c56a96c43502379bbd263692bfea;hpb=90afa5de6f3fa89a733861e843377302479fcf7e;p=safe%2Fjmp%2Flinux-2.6 diff --git a/mm/vmscan.c b/mm/vmscan.c index 79a98d9..3ff3311 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -13,7 +13,7 @@ #include #include -#include +#include #include #include #include @@ -55,6 +55,11 @@ struct scan_control { /* Number of pages freed so far during a call to shrink_zones() */ unsigned long nr_reclaimed; + /* How many pages shrink_list() should reclaim */ + unsigned long nr_to_reclaim; + + unsigned long hibernation_mode; + /* This context's GFP mask */ gfp_t gfp_mask; @@ -66,12 +71,6 @@ struct scan_control { /* Can pages be swapped as part of reclaim? */ int may_swap; - /* This context's SWAP_CLUSTER_MAX. If freeing memory for - * suspend, we effectively ignore SWAP_CLUSTER_MAX. - * In this context, it doesn't matter that we scan the - * whole list at once. */ - int swap_cluster_max; - int swappiness; int all_unreclaimable; @@ -148,8 +147,8 @@ static struct zone_reclaim_stat *get_reclaim_stat(struct zone *zone, return &zone->reclaim_stat; } -static unsigned long zone_nr_pages(struct zone *zone, struct scan_control *sc, - enum lru_list lru) +static unsigned long zone_nr_lru_pages(struct zone *zone, + struct scan_control *sc, enum lru_list lru) { if (!scanning_global_lru(sc)) return mem_cgroup_zone_nr_pages(sc->mem_cgroup, zone, lru); @@ -263,30 +262,14 @@ unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask, return ret; } -/* Called without lock on whether page is mapped, so answer is unstable */ -static inline int page_mapping_inuse(struct page *page) -{ - struct address_space *mapping; - - /* Page is in somebody's page tables. */ - if (page_mapped(page)) - return 1; - - /* Be more reluctant to reclaim swapcache than pagecache */ - if (PageSwapCache(page)) - return 1; - - mapping = page_mapping(page); - if (!mapping) - return 0; - - /* File is mmap'd by somebody? */ - return mapping_mapped(mapping); -} - static inline int is_page_cache_freeable(struct page *page) { - return page_count(page) - !!page_has_private(page) == 2; + /* + * A freeable page cache page is referenced only by the caller + * that isolated the page, the page cache radix tree and + * optional buffer heads at page->private. + */ + return page_count(page) - page_has_private(page) == 2; } static int may_write_to_queue(struct backing_dev_info *bdi) @@ -353,7 +336,7 @@ static pageout_t pageout(struct page *page, struct address_space *mapping, * stalls if we need to run get_block(). We could test * PagePrivate for that. * - * If this process is currently in generic_file_write() against + * If this process is currently in __generic_file_aio_write() against * this page's queue, we can perform writeback even if that * will block. * @@ -361,7 +344,6 @@ static pageout_t pageout(struct page *page, struct address_space *mapping, * block, for some throttling. This happens by accident, because * swap_backing_dev_info is bust: it doesn't reflect the * congestion state of the swapdevs. Easy to fix, if needed. - * See swapfile.c:page_queue_congested(). */ if (!is_page_cache_freeable(page)) return PAGE_KEEP; @@ -531,7 +513,7 @@ redo: * unevictable page on [in]active list. * We know how to handle that. */ - lru = active + page_is_file_cache(page); + lru = active + page_lru_base_type(page); lru_cache_add_lru(page, lru); } else { /* @@ -540,6 +522,16 @@ redo: */ lru = LRU_UNEVICTABLE; add_page_to_unevictable_list(page); + /* + * When racing with an mlock clearing (page is + * unlocked), make sure that if the other thread does + * not observe our setting of PG_lru and fails + * isolation, we see PG_mlocked cleared below and move + * the page back to the evictable list. + * + * The other side is TestClearPageMlocked(). + */ + smp_mb(); } /* @@ -566,6 +558,65 @@ redo: put_page(page); /* drop ref from isolate */ } +enum page_references { + PAGEREF_RECLAIM, + PAGEREF_RECLAIM_CLEAN, + PAGEREF_KEEP, + PAGEREF_ACTIVATE, +}; + +static enum page_references page_check_references(struct page *page, + struct scan_control *sc) +{ + int referenced_ptes, referenced_page; + unsigned long vm_flags; + + referenced_ptes = page_referenced(page, 1, sc->mem_cgroup, &vm_flags); + referenced_page = TestClearPageReferenced(page); + + /* Lumpy reclaim - ignore references */ + if (sc->order > PAGE_ALLOC_COSTLY_ORDER) + return PAGEREF_RECLAIM; + + /* + * Mlock lost the isolation race with us. Let try_to_unmap() + * move the page to the unevictable list. + */ + if (vm_flags & VM_LOCKED) + return PAGEREF_RECLAIM; + + if (referenced_ptes) { + if (PageAnon(page)) + return PAGEREF_ACTIVATE; + /* + * All mapped pages start out with page table + * references from the instantiating fault, so we need + * to look twice if a mapped file page is used more + * than once. + * + * Mark it and spare it for another trip around the + * inactive list. Another page table reference will + * lead to its activation. + * + * Note: the mark is set for activated pages as well + * so that recently deactivated but used pages are + * quickly recovered. + */ + SetPageReferenced(page); + + if (referenced_page) + return PAGEREF_ACTIVATE; + + return PAGEREF_KEEP; + } + + /* Reclaim if clean, defer dirty pages to writeback */ + if (referenced_page) + return PAGEREF_RECLAIM_CLEAN; + + return PAGEREF_RECLAIM; +} + /* * shrink_page_list() returns the number of reclaimed pages */ @@ -577,16 +628,15 @@ static unsigned long shrink_page_list(struct list_head *page_list, struct pagevec freed_pvec; int pgactivate = 0; unsigned long nr_reclaimed = 0; - unsigned long vm_flags; cond_resched(); pagevec_init(&freed_pvec, 1); while (!list_empty(page_list)) { + enum page_references references; struct address_space *mapping; struct page *page; int may_enter_fs; - int referenced; cond_resched(); @@ -628,12 +678,16 @@ static unsigned long shrink_page_list(struct list_head *page_list, goto keep_locked; } - referenced = page_referenced(page, 1, - sc->mem_cgroup, &vm_flags); - /* In active use or really unfreeable? Activate it. */ - if (sc->order <= PAGE_ALLOC_COSTLY_ORDER && - referenced && page_mapping_inuse(page)) + references = page_check_references(page, sc); + switch (references) { + case PAGEREF_ACTIVATE: goto activate_locked; + case PAGEREF_KEEP: + goto keep_locked; + case PAGEREF_RECLAIM: + case PAGEREF_RECLAIM_CLEAN: + ; /* try to reclaim the page below */ + } /* * Anonymous process memory has backing store? @@ -654,7 +708,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, * processes. Try to unmap it here. */ if (page_mapped(page) && mapping) { - switch (try_to_unmap(page, 0)) { + switch (try_to_unmap(page, TTU_UNMAP)) { case SWAP_FAIL: goto activate_locked; case SWAP_AGAIN: @@ -667,7 +721,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, } if (PageDirty(page)) { - if (sc->order <= PAGE_ALLOC_COSTLY_ORDER && referenced) + if (references == PAGEREF_RECLAIM_CLEAN) goto keep_locked; if (!may_enter_fs) goto keep_locked; @@ -816,7 +870,7 @@ int __isolate_lru_page(struct page *page, int mode, int file) if (mode != ISOLATE_BOTH && (!PageActive(page) != !mode)) return ret; - if (mode != ISOLATE_BOTH && (!page_is_file_cache(page) != !file)) + if (mode != ISOLATE_BOTH && page_is_file_cache(page) != file) return ret; /* @@ -837,7 +891,6 @@ int __isolate_lru_page(struct page *page, int mode, int file) */ ClearPageLRU(page); ret = 0; - mem_cgroup_del_lru(page); } return ret; @@ -885,12 +938,14 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, switch (__isolate_lru_page(page, mode, file)) { case 0: list_move(&page->lru, dst); + mem_cgroup_del_lru(page); nr_taken++; break; case -EBUSY: /* else it is being freed elsewhere */ list_move(&page->lru, src); + mem_cgroup_rotate_lru_list(page, page_lru(page)); continue; default: @@ -929,18 +984,21 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, /* Check that we have not crossed a zone boundary. */ if (unlikely(page_zone_id(cursor_page) != zone_id)) continue; - switch (__isolate_lru_page(cursor_page, mode, file)) { - case 0: + + /* + * If we don't have enough swap space, reclaiming of + * anon page which don't already have a swap slot is + * pointless. + */ + if (nr_swap_pages <= 0 && PageAnon(cursor_page) && + !PageSwapCache(cursor_page)) + continue; + + if (__isolate_lru_page(cursor_page, mode, file) == 0) { list_move(&cursor_page->lru, dst); + mem_cgroup_del_lru(cursor_page); nr_taken++; scan++; - break; - - case -EBUSY: - /* else it is being freed elsewhere */ - list_move(&cursor_page->lru, src); - default: - break; /* ! on LRU or wrong list */ } } } @@ -962,7 +1020,7 @@ static unsigned long isolate_pages_global(unsigned long nr, if (file) lru += LRU_FILE; return isolate_lru_pages(nr, &z->lru[lru].list, dst, scanned, order, - mode, !!file); + mode, file); } /* @@ -977,7 +1035,7 @@ static unsigned long clear_active_flags(struct list_head *page_list, struct page *page; list_for_each_entry(page, page_list, lru) { - lru = page_is_file_cache(page); + lru = page_lru_base_type(page); if (PageActive(page)) { lru += LRU_ACTIVE; ClearPageActive(page); @@ -1035,6 +1093,31 @@ int isolate_lru_page(struct page *page) } /* + * Are there way too many processes in the direct reclaim path already? + */ +static int too_many_isolated(struct zone *zone, int file, + struct scan_control *sc) +{ + unsigned long inactive, isolated; + + if (current_is_kswapd()) + return 0; + + if (!scanning_global_lru(sc)) + return 0; + + if (file) { + inactive = zone_page_state(zone, NR_INACTIVE_FILE); + isolated = zone_page_state(zone, NR_ISOLATED_FILE); + } else { + inactive = zone_page_state(zone, NR_INACTIVE_ANON); + isolated = zone_page_state(zone, NR_ISOLATED_ANON); + } + + return isolated > inactive; +} + +/* * shrink_inactive_list() is a helper for shrink_zone(). It returns the number * of reclaimed pages */ @@ -1049,6 +1132,14 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); int lumpy_reclaim = 0; + while (unlikely(too_many_isolated(zone, file, sc))) { + congestion_wait(BLK_RW_ASYNC, HZ/10); + + /* We are about to die and free our memory. Return now. */ + if (fatal_signal_pending(current)) + return SWAP_CLUSTER_MAX; + } + /* * If we need a large contiguous chunk of memory, or have * trouble getting a small set of contiguous pages, we @@ -1073,10 +1164,26 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, unsigned long nr_active; unsigned int count[NR_LRU_LISTS] = { 0, }; int mode = lumpy_reclaim ? ISOLATE_BOTH : ISOLATE_INACTIVE; + unsigned long nr_anon; + unsigned long nr_file; - nr_taken = sc->isolate_pages(sc->swap_cluster_max, + nr_taken = sc->isolate_pages(SWAP_CLUSTER_MAX, &page_list, &nr_scan, sc->order, mode, zone, sc->mem_cgroup, 0, file); + + if (scanning_global_lru(sc)) { + zone->pages_scanned += nr_scan; + if (current_is_kswapd()) + __count_zone_vm_events(PGSCAN_KSWAPD, zone, + nr_scan); + else + __count_zone_vm_events(PGSCAN_DIRECT, zone, + nr_scan); + } + + if (nr_taken == 0) + goto done; + nr_active = clear_active_flags(&page_list, count); __count_vm_events(PGDEACTIVATE, nr_active); @@ -1089,13 +1196,13 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, __mod_zone_page_state(zone, NR_INACTIVE_ANON, -count[LRU_INACTIVE_ANON]); - if (scanning_global_lru(sc)) - zone->pages_scanned += nr_scan; + nr_anon = count[LRU_ACTIVE_ANON] + count[LRU_INACTIVE_ANON]; + nr_file = count[LRU_ACTIVE_FILE] + count[LRU_INACTIVE_FILE]; + __mod_zone_page_state(zone, NR_ISOLATED_ANON, nr_anon); + __mod_zone_page_state(zone, NR_ISOLATED_FILE, nr_file); - reclaim_stat->recent_scanned[0] += count[LRU_INACTIVE_ANON]; - reclaim_stat->recent_scanned[0] += count[LRU_ACTIVE_ANON]; - reclaim_stat->recent_scanned[1] += count[LRU_INACTIVE_FILE]; - reclaim_stat->recent_scanned[1] += count[LRU_ACTIVE_FILE]; + reclaim_stat->recent_scanned[0] += nr_anon; + reclaim_stat->recent_scanned[1] += nr_file; spin_unlock_irq(&zone->lru_lock); @@ -1110,7 +1217,7 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, */ if (nr_freed < nr_taken && !current_is_kswapd() && lumpy_reclaim) { - congestion_wait(WRITE, HZ/10); + congestion_wait(BLK_RW_ASYNC, HZ/10); /* * The attempt at page out may have made some @@ -1124,18 +1231,12 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, } nr_reclaimed += nr_freed; + local_irq_disable(); - if (current_is_kswapd()) { - __count_zone_vm_events(PGSCAN_KSWAPD, zone, nr_scan); + if (current_is_kswapd()) __count_vm_events(KSWAPD_STEAL, nr_freed); - } else if (scanning_global_lru(sc)) - __count_zone_vm_events(PGSCAN_DIRECT, zone, nr_scan); - __count_zone_vm_events(PGSTEAL, zone, nr_freed); - if (nr_taken == 0) - goto done; - spin_lock(&zone->lru_lock); /* * Put back any unfreeable pages. @@ -1154,8 +1255,8 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, SetPageLRU(page); lru = page_lru(page); add_page_to_lru_list(zone, page, lru); - if (PageActive(page)) { - int file = !!page_is_file_cache(page); + if (is_active_lru(lru)) { + int file = is_file_lru(lru); reclaim_stat->recent_rotated[file]++; } if (!pagevec_add(&pvec, page)) { @@ -1164,10 +1265,13 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, spin_lock_irq(&zone->lru_lock); } } + __mod_zone_page_state(zone, NR_ISOLATED_ANON, -nr_anon); + __mod_zone_page_state(zone, NR_ISOLATED_FILE, -nr_file); + } while (nr_scanned < max_scan); - spin_unlock(&zone->lru_lock); + done: - local_irq_enable(); + spin_unlock_irq(&zone->lru_lock); pagevec_release(&pvec); return nr_reclaimed; } @@ -1216,15 +1320,10 @@ static void move_active_pages_to_lru(struct zone *zone, while (!list_empty(list)) { page = lru_to_page(list); - prefetchw_prev_lru_page(page, list, flags); VM_BUG_ON(PageLRU(page)); SetPageLRU(page); - VM_BUG_ON(!PageActive(page)); - if (!is_active_lru(lru)) - ClearPageActive(page); /* we are de-activating */ - list_move(&page->lru, &zone->lru[lru].list); mem_cgroup_add_lru_list(page, lru); pgmoved++; @@ -1245,7 +1344,7 @@ static void move_active_pages_to_lru(struct zone *zone, static void shrink_active_list(unsigned long nr_pages, struct zone *zone, struct scan_control *sc, int priority, int file) { - unsigned long pgmoved; + unsigned long nr_taken; unsigned long pgscanned; unsigned long vm_flags; LIST_HEAD(l_hold); /* The pages which were snipped off */ @@ -1253,10 +1352,11 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone, LIST_HEAD(l_inactive); struct page *page; struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); + unsigned long nr_rotated = 0; lru_add_drain(); spin_lock_irq(&zone->lru_lock); - pgmoved = sc->isolate_pages(nr_pages, &l_hold, &pgscanned, sc->order, + nr_taken = sc->isolate_pages(nr_pages, &l_hold, &pgscanned, sc->order, ISOLATE_ACTIVE, zone, sc->mem_cgroup, 1, file); /* @@ -1266,16 +1366,16 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone, if (scanning_global_lru(sc)) { zone->pages_scanned += pgscanned; } - reclaim_stat->recent_scanned[!!file] += pgmoved; + reclaim_stat->recent_scanned[file] += nr_taken; __count_zone_vm_events(PGREFILL, zone, pgscanned); if (file) - __mod_zone_page_state(zone, NR_ACTIVE_FILE, -pgmoved); + __mod_zone_page_state(zone, NR_ACTIVE_FILE, -nr_taken); else - __mod_zone_page_state(zone, NR_ACTIVE_ANON, -pgmoved); + __mod_zone_page_state(zone, NR_ACTIVE_ANON, -nr_taken); + __mod_zone_page_state(zone, NR_ISOLATED_ANON + file, nr_taken); spin_unlock_irq(&zone->lru_lock); - pgmoved = 0; /* count referenced (mapping) mapped pages */ while (!list_empty(&l_hold)) { cond_resched(); page = lru_to_page(&l_hold); @@ -1286,10 +1386,8 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone, continue; } - /* page_referenced clears PageReferenced */ - if (page_mapping_inuse(page) && - page_referenced(page, 0, sc->mem_cgroup, &vm_flags)) { - pgmoved++; + if (page_referenced(page, 0, sc->mem_cgroup, &vm_flags)) { + nr_rotated++; /* * Identify referenced, file-backed active pages and * give them one more trip around the active list. So @@ -1299,12 +1397,13 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone, * IO, plus JVM can create lots of anon VM_EXEC pages, * so we ignore them here. */ - if ((vm_flags & VM_EXEC) && !PageAnon(page)) { + if ((vm_flags & VM_EXEC) && page_is_file_cache(page)) { list_add(&page->lru, &l_active); continue; } } + ClearPageActive(page); /* we are de-activating */ list_add(&page->lru, &l_inactive); } @@ -1318,13 +1417,13 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone, * helps balance scan pressure between file and anonymous pages in * get_scan_ratio. */ - reclaim_stat->recent_rotated[!!file] += pgmoved; + reclaim_stat->recent_rotated[file] += nr_rotated; move_active_pages_to_lru(zone, &l_active, LRU_ACTIVE + file * LRU_FILE); move_active_pages_to_lru(zone, &l_inactive, LRU_BASE + file * LRU_FILE); - + __mod_zone_page_state(zone, NR_ISOLATED_ANON + file, -nr_taken); spin_unlock_irq(&zone->lru_lock); } @@ -1396,20 +1495,26 @@ static int inactive_file_is_low(struct zone *zone, struct scan_control *sc) return low; } +static int inactive_list_is_low(struct zone *zone, struct scan_control *sc, + int file) +{ + if (file) + return inactive_file_is_low(zone, sc); + else + return inactive_anon_is_low(zone, sc); +} + static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan, struct zone *zone, struct scan_control *sc, int priority) { int file = is_file_lru(lru); - if (lru == LRU_ACTIVE_FILE && inactive_file_is_low(zone, sc)) { - shrink_active_list(nr_to_scan, zone, sc, priority, file); + if (is_active_lru(lru)) { + if (inactive_list_is_low(zone, sc, file)) + shrink_active_list(nr_to_scan, zone, sc, priority, file); return 0; } - if (lru == LRU_ACTIVE_ANON && inactive_anon_is_low(zone, sc)) { - shrink_active_list(nr_to_scan, zone, sc, priority, file); - return 0; - } return shrink_inactive_list(nr_to_scan, zone, sc, priority, file); } @@ -1430,10 +1535,10 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc, unsigned long ap, fp; struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); - anon = zone_nr_pages(zone, sc, LRU_ACTIVE_ANON) + - zone_nr_pages(zone, sc, LRU_INACTIVE_ANON); - file = zone_nr_pages(zone, sc, LRU_ACTIVE_FILE) + - zone_nr_pages(zone, sc, LRU_INACTIVE_FILE); + anon = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_ANON) + + zone_nr_lru_pages(zone, sc, LRU_INACTIVE_ANON); + file = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_FILE) + + zone_nr_lru_pages(zone, sc, LRU_INACTIVE_FILE); if (scanning_global_lru(sc)) { free = zone_page_state(zone, NR_FREE_PAGES); @@ -1499,15 +1604,14 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc, * until we collected @swap_cluster_max pages to scan. */ static unsigned long nr_scan_try_batch(unsigned long nr_to_scan, - unsigned long *nr_saved_scan, - unsigned long swap_cluster_max) + unsigned long *nr_saved_scan) { unsigned long nr; *nr_saved_scan += nr_to_scan; nr = *nr_saved_scan; - if (nr >= swap_cluster_max) + if (nr >= SWAP_CLUSTER_MAX) *nr_saved_scan = 0; else nr = 0; @@ -1526,7 +1630,8 @@ static void shrink_zone(int priority, struct zone *zone, unsigned long percent[2]; /* anon @ 0; file @ 1 */ enum lru_list l; unsigned long nr_reclaimed = sc->nr_reclaimed; - unsigned long swap_cluster_max = sc->swap_cluster_max; + unsigned long nr_to_reclaim = sc->nr_to_reclaim; + struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); int noswap = 0; /* If we have no swap space, do not bother scanning anon pages. */ @@ -1541,24 +1646,21 @@ static void shrink_zone(int priority, struct zone *zone, int file = is_file_lru(l); unsigned long scan; - scan = zone_nr_pages(zone, sc, l); + scan = zone_nr_lru_pages(zone, sc, l); if (priority || noswap) { scan >>= priority; scan = (scan * percent[file]) / 100; } - if (scanning_global_lru(sc)) - nr[l] = nr_scan_try_batch(scan, - &zone->lru[l].nr_saved_scan, - swap_cluster_max); - else - nr[l] = scan; + nr[l] = nr_scan_try_batch(scan, + &reclaim_stat->nr_saved_scan[l]); } while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] || nr[LRU_INACTIVE_FILE]) { for_each_evictable_lru(l) { if (nr[l]) { - nr_to_scan = min(nr[l], swap_cluster_max); + nr_to_scan = min_t(unsigned long, + nr[l], SWAP_CLUSTER_MAX); nr[l] -= nr_to_scan; nr_reclaimed += shrink_list(l, nr_to_scan, @@ -1573,8 +1675,7 @@ static void shrink_zone(int priority, struct zone *zone, * with multiple processes reclaiming pages, the total * freeing target can get unreasonably large. */ - if (nr_reclaimed > swap_cluster_max && - priority < DEF_PRIORITY && !current_is_kswapd()) + if (nr_reclaimed >= nr_to_reclaim && priority < DEF_PRIORITY) break; } @@ -1627,8 +1728,7 @@ static void shrink_zones(int priority, struct zonelist *zonelist, continue; note_zone_scanning_priority(zone, priority); - if (zone_is_all_unreclaimable(zone) && - priority != DEF_PRIORITY) + if (zone->all_unreclaimable && priority != DEF_PRIORITY) continue; /* Let kswapd poll it */ sc->all_unreclaimable = 0; } else { @@ -1653,10 +1753,10 @@ static void shrink_zones(int priority, struct zonelist *zonelist, * * If the caller is !__GFP_FS then the probability of a failure is reasonably * high - the zone may be full of dirty or under-writeback pages, which this - * caller can't do much about. We kick pdflush and take explicit naps in the - * hope that some of these pages can be written. But if the allocating task - * holds filesystem locks which prevent writeout this might not work, and the - * allocation attempt will fail. + * caller can't do much about. We kick the writeback threads and take explicit + * naps in the hope that some of these pages can be written. But if the + * allocating task holds filesystem locks which prevent writeout this might not + * work, and the allocation attempt will fail. * * returns: 0, if no pages reclaimed * else, the number of pages reclaimed @@ -1672,6 +1772,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, struct zoneref *z; struct zone *zone; enum zone_type high_zoneidx = gfp_zone(sc->gfp_mask); + unsigned long writeback_threshold; delayacct_freepages_start(); @@ -1686,7 +1787,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) continue; - lru_pages += zone_lru_pages(zone); + lru_pages += zone_reclaimable_pages(zone); } } @@ -1707,7 +1808,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, } } total_scanned += sc->nr_scanned; - if (sc->nr_reclaimed >= sc->swap_cluster_max) { + if (sc->nr_reclaimed >= sc->nr_to_reclaim) { ret = sc->nr_reclaimed; goto out; } @@ -1719,15 +1820,16 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, * that's undesirable in laptop mode, where we *want* lumpy * writeout. So in laptop mode, write out the whole world. */ - if (total_scanned > sc->swap_cluster_max + - sc->swap_cluster_max / 2) { - wakeup_pdflush(laptop_mode ? 0 : total_scanned); + writeback_threshold = sc->nr_to_reclaim + sc->nr_to_reclaim / 2; + if (total_scanned > writeback_threshold) { + wakeup_flusher_threads(laptop_mode ? 0 : total_scanned); sc->may_writepage = 1; } /* Take a nap, wait for some writeback to complete */ - if (sc->nr_scanned && priority < DEF_PRIORITY - 2) - congestion_wait(WRITE, HZ/10); + if (!sc->hibernation_mode && sc->nr_scanned && + priority < DEF_PRIORITY - 2) + congestion_wait(BLK_RW_ASYNC, HZ/10); } /* top priority shrink_zones still had more to do? don't OOM, then */ if (!sc->all_unreclaimable && scanning_global_lru(sc)) @@ -1765,7 +1867,7 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order, struct scan_control sc = { .gfp_mask = gfp_mask, .may_writepage = !laptop_mode, - .swap_cluster_max = SWAP_CLUSTER_MAX, + .nr_to_reclaim = SWAP_CLUSTER_MAX, .may_unmap = 1, .may_swap = 1, .swappiness = vm_swappiness, @@ -1780,23 +1882,55 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order, #ifdef CONFIG_CGROUP_MEM_RES_CTLR +unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem, + gfp_t gfp_mask, bool noswap, + unsigned int swappiness, + struct zone *zone, int nid) +{ + struct scan_control sc = { + .may_writepage = !laptop_mode, + .may_unmap = 1, + .may_swap = !noswap, + .swappiness = swappiness, + .order = 0, + .mem_cgroup = mem, + .isolate_pages = mem_cgroup_isolate_pages, + }; + nodemask_t nm = nodemask_of_node(nid); + + sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) | + (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK); + sc.nodemask = &nm; + sc.nr_reclaimed = 0; + sc.nr_scanned = 0; + /* + * NOTE: Although we can get the priority field, using it + * here is not a good idea, since it limits the pages we can scan. + * if we don't reclaim here, the shrink_zone from balance_pgdat + * will pick up pages from other mem cgroup's as well. We hack + * the priority and make it zero. + */ + shrink_zone(0, zone, &sc); + return sc.nr_reclaimed; +} + unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont, gfp_t gfp_mask, bool noswap, unsigned int swappiness) { + struct zonelist *zonelist; struct scan_control sc = { .may_writepage = !laptop_mode, .may_unmap = 1, .may_swap = !noswap, - .swap_cluster_max = SWAP_CLUSTER_MAX, + .nr_to_reclaim = SWAP_CLUSTER_MAX, .swappiness = swappiness, .order = 0, .mem_cgroup = mem_cont, .isolate_pages = mem_cgroup_isolate_pages, .nodemask = NULL, /* we don't care the placement */ }; - struct zonelist *zonelist; sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) | (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK); @@ -1805,6 +1939,33 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont, } #endif +/* is kswapd sleeping prematurely? */ +static int sleeping_prematurely(pg_data_t *pgdat, int order, long remaining) +{ + int i; + + /* If a direct reclaimer woke kswapd within HZ/10, it's premature */ + if (remaining) + return 1; + + /* If after HZ/10, a zone is below the high mark, it's premature */ + for (i = 0; i < pgdat->nr_zones; i++) { + struct zone *zone = pgdat->node_zones + i; + + if (!populated_zone(zone)) + continue; + + if (zone->all_unreclaimable) + continue; + + if (!zone_watermark_ok(zone, order, high_wmark_pages(zone), + 0, 0)) + return 1; + } + + return 0; +} + /* * For kswapd, balance_pgdat() will work across all this node's zones until * they are all at high_wmark_pages(zone). @@ -1837,7 +1998,11 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order) .gfp_mask = GFP_KERNEL, .may_unmap = 1, .may_swap = 1, - .swap_cluster_max = SWAP_CLUSTER_MAX, + /* + * kswapd doesn't want to be bailed out while reclaim. because + * we want to put equal scanning pressure on each zone. + */ + .nr_to_reclaim = ULONG_MAX, .swappiness = vm_swappiness, .order = order, .mem_cgroup = NULL, @@ -1862,6 +2027,7 @@ loop_again: for (priority = DEF_PRIORITY; priority >= 0; priority--) { int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */ unsigned long lru_pages = 0; + int has_under_min_watermark_zone = 0; /* The swap token gets in the way of swapout... */ if (!priority) @@ -1879,8 +2045,7 @@ loop_again: if (!populated_zone(zone)) continue; - if (zone_is_all_unreclaimable(zone) && - priority != DEF_PRIORITY) + if (zone->all_unreclaimable && priority != DEF_PRIORITY) continue; /* @@ -1903,7 +2068,7 @@ loop_again: for (i = 0; i <= end_zone; i++) { struct zone *zone = pgdat->node_zones + i; - lru_pages += zone_lru_pages(zone); + lru_pages += zone_reclaimable_pages(zone); } /* @@ -1918,20 +2083,26 @@ loop_again: for (i = 0; i <= end_zone; i++) { struct zone *zone = pgdat->node_zones + i; int nr_slab; + int nid, zid; if (!populated_zone(zone)) continue; - if (zone_is_all_unreclaimable(zone) && - priority != DEF_PRIORITY) + if (zone->all_unreclaimable && priority != DEF_PRIORITY) continue; - if (!zone_watermark_ok(zone, order, - high_wmark_pages(zone), end_zone, 0)) - all_zones_ok = 0; temp_priority[i] = priority; sc.nr_scanned = 0; note_zone_scanning_priority(zone, priority); + + nid = pgdat->node_id; + zid = zone_idx(zone); + /* + * Call soft limit reclaim before calling shrink_zone. + * For now we ignore the return value + */ + mem_cgroup_soft_limit_reclaim(zone, order, sc.gfp_mask, + nid, zid); /* * We put equal pressure on every zone, unless one * zone has way too many pages free already. @@ -1944,12 +2115,11 @@ loop_again: lru_pages); sc.nr_reclaimed += reclaim_state->reclaimed_slab; total_scanned += sc.nr_scanned; - if (zone_is_all_unreclaimable(zone)) + if (zone->all_unreclaimable) continue; - if (nr_slab == 0 && zone->pages_scanned >= - (zone_lru_pages(zone) * 6)) - zone_set_flag(zone, - ZONE_ALL_UNRECLAIMABLE); + if (nr_slab == 0 && + zone->pages_scanned >= (zone_reclaimable_pages(zone) * 6)) + zone->all_unreclaimable = 1; /* * If we've done a decent amount of scanning and * the reclaim ratio is low, start doing writepage @@ -1958,6 +2128,20 @@ loop_again: if (total_scanned > SWAP_CLUSTER_MAX * 2 && total_scanned > sc.nr_reclaimed + sc.nr_reclaimed / 2) sc.may_writepage = 1; + + if (!zone_watermark_ok(zone, order, + high_wmark_pages(zone), end_zone, 0)) { + all_zones_ok = 0; + /* + * We are still under min water mark. This + * means that we have a GFP_ATOMIC allocation + * failure risk. Hurry up! + */ + if (!zone_watermark_ok(zone, order, + min_wmark_pages(zone), end_zone, 0)) + has_under_min_watermark_zone = 1; + } + } if (all_zones_ok) break; /* kswapd: all done */ @@ -1965,8 +2149,12 @@ loop_again: * OK, kswapd is getting into trouble. Take a nap, then take * another pass across the zones. */ - if (total_scanned && priority < DEF_PRIORITY - 2) - congestion_wait(WRITE, HZ/10); + if (total_scanned && (priority < DEF_PRIORITY - 2)) { + if (has_under_min_watermark_zone) + count_vm_event(KSWAPD_SKIP_CONGESTION_WAIT); + else + congestion_wait(BLK_RW_ASYNC, HZ/10); + } /* * We do this so kswapd doesn't build up large priorities for @@ -2064,6 +2252,7 @@ static int kswapd(void *p) order = 0; for ( ; ; ) { unsigned long new_order; + int ret; prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); new_order = pgdat->kswapd_max_order; @@ -2075,19 +2264,45 @@ static int kswapd(void *p) */ order = new_order; } else { - if (!freezing(current)) - schedule(); + if (!freezing(current) && !kthread_should_stop()) { + long remaining = 0; + + /* Try to sleep for a short interval */ + if (!sleeping_prematurely(pgdat, order, remaining)) { + remaining = schedule_timeout(HZ/10); + finish_wait(&pgdat->kswapd_wait, &wait); + prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); + } + + /* + * After a short sleep, check if it was a + * premature sleep. If not, then go fully + * to sleep until explicitly woken up + */ + if (!sleeping_prematurely(pgdat, order, remaining)) + schedule(); + else { + if (remaining) + count_vm_event(KSWAPD_LOW_WMARK_HIT_QUICKLY); + else + count_vm_event(KSWAPD_HIGH_WMARK_HIT_QUICKLY); + } + } order = pgdat->kswapd_max_order; } finish_wait(&pgdat->kswapd_wait, &wait); - if (!try_to_freeze()) { - /* We can speed up thawing tasks if we don't call - * balance_pgdat after returning from the refrigerator - */ + ret = try_to_freeze(); + if (kthread_should_stop()) + break; + + /* + * We can speed up thawing tasks if we don't call balance_pgdat + * after returning from the refrigerator + */ + if (!ret) balance_pgdat(pgdat, order); - } } return 0; } @@ -2114,153 +2329,80 @@ void wakeup_kswapd(struct zone *zone, int order) wake_up_interruptible(&pgdat->kswapd_wait); } -unsigned long global_lru_pages(void) -{ - return global_page_state(NR_ACTIVE_ANON) - + global_page_state(NR_ACTIVE_FILE) - + global_page_state(NR_INACTIVE_ANON) - + global_page_state(NR_INACTIVE_FILE); -} - -#ifdef CONFIG_HIBERNATION /* - * Helper function for shrink_all_memory(). Tries to reclaim 'nr_pages' pages - * from LRU lists system-wide, for given pass and priority. - * - * For pass > 3 we also try to shrink the LRU lists that contain a few pages + * The reclaimable count would be mostly accurate. + * The less reclaimable pages may be + * - mlocked pages, which will be moved to unevictable list when encountered + * - mapped pages, which may require several travels to be reclaimed + * - dirty pages, which is not "instantly" reclaimable */ -static void shrink_all_zones(unsigned long nr_pages, int prio, - int pass, struct scan_control *sc) +unsigned long global_reclaimable_pages(void) { - struct zone *zone; - unsigned long nr_reclaimed = 0; + int nr; - for_each_populated_zone(zone) { - enum lru_list l; + nr = global_page_state(NR_ACTIVE_FILE) + + global_page_state(NR_INACTIVE_FILE); - if (zone_is_all_unreclaimable(zone) && prio != DEF_PRIORITY) - continue; + if (nr_swap_pages > 0) + nr += global_page_state(NR_ACTIVE_ANON) + + global_page_state(NR_INACTIVE_ANON); - for_each_evictable_lru(l) { - enum zone_stat_item ls = NR_LRU_BASE + l; - unsigned long lru_pages = zone_page_state(zone, ls); + return nr; +} - /* For pass = 0, we don't shrink the active list */ - if (pass == 0 && (l == LRU_ACTIVE_ANON || - l == LRU_ACTIVE_FILE)) - continue; +unsigned long zone_reclaimable_pages(struct zone *zone) +{ + int nr; - zone->lru[l].nr_saved_scan += (lru_pages >> prio) + 1; - if (zone->lru[l].nr_saved_scan >= nr_pages || pass > 3) { - unsigned long nr_to_scan; - - zone->lru[l].nr_saved_scan = 0; - nr_to_scan = min(nr_pages, lru_pages); - nr_reclaimed += shrink_list(l, nr_to_scan, zone, - sc, prio); - if (nr_reclaimed >= nr_pages) { - sc->nr_reclaimed += nr_reclaimed; - return; - } - } - } - } - sc->nr_reclaimed += nr_reclaimed; + nr = zone_page_state(zone, NR_ACTIVE_FILE) + + zone_page_state(zone, NR_INACTIVE_FILE); + + if (nr_swap_pages > 0) + nr += zone_page_state(zone, NR_ACTIVE_ANON) + + zone_page_state(zone, NR_INACTIVE_ANON); + + return nr; } +#ifdef CONFIG_HIBERNATION /* - * Try to free `nr_pages' of memory, system-wide, and return the number of + * Try to free `nr_to_reclaim' of memory, system-wide, and return the number of * freed pages. * * Rather than trying to age LRUs the aim is to preserve the overall * LRU order by reclaiming preferentially * inactive > active > active referenced > active mapped */ -unsigned long shrink_all_memory(unsigned long nr_pages) +unsigned long shrink_all_memory(unsigned long nr_to_reclaim) { - unsigned long lru_pages, nr_slab; - int pass; struct reclaim_state reclaim_state; struct scan_control sc = { - .gfp_mask = GFP_KERNEL, - .may_unmap = 0, + .gfp_mask = GFP_HIGHUSER_MOVABLE, + .may_swap = 1, + .may_unmap = 1, .may_writepage = 1, + .nr_to_reclaim = nr_to_reclaim, + .hibernation_mode = 1, + .swappiness = vm_swappiness, + .order = 0, .isolate_pages = isolate_pages_global, - .nr_reclaimed = 0, }; + struct zonelist * zonelist = node_zonelist(numa_node_id(), sc.gfp_mask); + struct task_struct *p = current; + unsigned long nr_reclaimed; - current->reclaim_state = &reclaim_state; - - lru_pages = global_lru_pages(); - nr_slab = global_page_state(NR_SLAB_RECLAIMABLE); - /* If slab caches are huge, it's better to hit them first */ - while (nr_slab >= lru_pages) { - reclaim_state.reclaimed_slab = 0; - shrink_slab(nr_pages, sc.gfp_mask, lru_pages); - if (!reclaim_state.reclaimed_slab) - break; - - sc.nr_reclaimed += reclaim_state.reclaimed_slab; - if (sc.nr_reclaimed >= nr_pages) - goto out; - - nr_slab -= reclaim_state.reclaimed_slab; - } - - /* - * We try to shrink LRUs in 5 passes: - * 0 = Reclaim from inactive_list only - * 1 = Reclaim from active list but don't reclaim mapped - * 2 = 2nd pass of type 1 - * 3 = Reclaim mapped (normal reclaim) - * 4 = 2nd pass of type 3 - */ - for (pass = 0; pass < 5; pass++) { - int prio; - - /* Force reclaiming mapped pages in the passes #3 and #4 */ - if (pass > 2) - sc.may_unmap = 1; - - for (prio = DEF_PRIORITY; prio >= 0; prio--) { - unsigned long nr_to_scan = nr_pages - sc.nr_reclaimed; - - sc.nr_scanned = 0; - sc.swap_cluster_max = nr_to_scan; - shrink_all_zones(nr_to_scan, prio, pass, &sc); - if (sc.nr_reclaimed >= nr_pages) - goto out; - - reclaim_state.reclaimed_slab = 0; - shrink_slab(sc.nr_scanned, sc.gfp_mask, - global_lru_pages()); - sc.nr_reclaimed += reclaim_state.reclaimed_slab; - if (sc.nr_reclaimed >= nr_pages) - goto out; - - if (sc.nr_scanned && prio < DEF_PRIORITY - 2) - congestion_wait(WRITE, HZ / 10); - } - } - - /* - * If sc.nr_reclaimed = 0, we could not shrink LRUs, but there may be - * something in slab caches - */ - if (!sc.nr_reclaimed) { - do { - reclaim_state.reclaimed_slab = 0; - shrink_slab(nr_pages, sc.gfp_mask, global_lru_pages()); - sc.nr_reclaimed += reclaim_state.reclaimed_slab; - } while (sc.nr_reclaimed < nr_pages && - reclaim_state.reclaimed_slab > 0); - } + p->flags |= PF_MEMALLOC; + lockdep_set_current_reclaim_state(sc.gfp_mask); + reclaim_state.reclaimed_slab = 0; + p->reclaim_state = &reclaim_state; + nr_reclaimed = do_try_to_free_pages(zonelist, &sc); -out: - current->reclaim_state = NULL; + p->reclaim_state = NULL; + lockdep_clear_current_reclaim_state(); + p->flags &= ~PF_MEMALLOC; - return sc.nr_reclaimed; + return nr_reclaimed; } #endif /* CONFIG_HIBERNATION */ @@ -2310,6 +2452,17 @@ int kswapd_run(int nid) return ret; } +/* + * Called by memory hotplug when all memory in a node is offlined. + */ +void kswapd_stop(int nid) +{ + struct task_struct *kswapd = NODE_DATA(nid)->kswapd; + + if (kswapd) + kthread_stop(kswapd); +} + static int __init kswapd_init(void) { int nid; @@ -2412,8 +2565,8 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) .may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE), .may_unmap = !!(zone_reclaim_mode & RECLAIM_SWAP), .may_swap = 1, - .swap_cluster_max = max_t(unsigned long, nr_pages, - SWAP_CLUSTER_MAX), + .nr_to_reclaim = max_t(unsigned long, nr_pages, + SWAP_CLUSTER_MAX), .gfp_mask = gfp_mask, .swappiness = vm_swappiness, .order = order, @@ -2429,6 +2582,7 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) * and RECLAIM_SWAP. */ p->flags |= PF_MEMALLOC | PF_SWAPWRITE; + lockdep_set_current_reclaim_state(gfp_mask); reclaim_state.reclaimed_slab = 0; p->reclaim_state = &reclaim_state; @@ -2472,6 +2626,7 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) p->reclaim_state = NULL; current->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE); + lockdep_clear_current_reclaim_state(); return sc.nr_reclaimed >= nr_pages; } @@ -2492,16 +2647,16 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) */ if (zone_pagecache_reclaimable(zone) <= zone->min_unmapped_pages && zone_page_state(zone, NR_SLAB_RECLAIMABLE) <= zone->min_slab_pages) - return 0; + return ZONE_RECLAIM_FULL; - if (zone_is_all_unreclaimable(zone)) - return 0; + if (zone->all_unreclaimable) + return ZONE_RECLAIM_FULL; /* * Do not scan if the allocation should not be delayed. */ if (!(gfp_mask & __GFP_WAIT) || (current->flags & PF_MEMALLOC)) - return 0; + return ZONE_RECLAIM_NOSCAN; /* * Only run zone reclaim on the local zone or on zones that do not @@ -2511,13 +2666,17 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) */ node_id = zone_to_nid(zone); if (node_state(node_id, N_CPU) && node_id != numa_node_id()) - return 0; + return ZONE_RECLAIM_NOSCAN; if (zone_test_and_set_flag(zone, ZONE_RECLAIM_LOCKED)) - return 0; + return ZONE_RECLAIM_NOSCAN; + ret = __zone_reclaim(zone, gfp_mask, order); zone_clear_flag(zone, ZONE_RECLAIM_LOCKED); + if (!ret) + count_vm_event(PGSCAN_ZONE_RECLAIM_FAILED); + return ret; } #endif @@ -2566,7 +2725,7 @@ static void check_move_unevictable_page(struct page *page, struct zone *zone) retry: ClearPageUnevictable(page); if (page_evictable(page, NULL)) { - enum lru_list l = LRU_INACTIVE_ANON + page_is_file_cache(page); + enum lru_list l = page_lru_base_type(page); __dec_zone_state(zone, NR_UNEVICTABLE); list_move(&page->lru, &zone->lru[l].list); @@ -2709,10 +2868,10 @@ static void scan_all_zones_unevictable_pages(void) unsigned long scan_unevictable_pages; int scan_unevictable_handler(struct ctl_table *table, int write, - struct file *file, void __user *buffer, + void __user *buffer, size_t *length, loff_t *ppos) { - proc_doulongvec_minmax(table, write, file, buffer, length, ppos); + proc_doulongvec_minmax(table, write, buffer, length, ppos); if (write && *(unsigned long *)table->data) scan_all_zones_unevictable_pages();