X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=mm%2Fvmscan.c;h=840092d46a90244a5a0ad23aedde2bdf030ab928;hb=43bc926fffd92024b46cafaf7350d669ba9ca884;hp=2395eeb6ea0d5d67ac956b1d317e84cd6d44f20e;hpb=cee37fe97739d85991964371c1f3a745c00dd236;p=linux-2.6.git diff --git a/mm/vmscan.c b/mm/vmscan.c index 2395eeb6e..840092d46 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -33,47 +33,29 @@ #include #include #include +#include #include #include #include -/* possible outcome of pageout() */ -typedef enum { - /* failed to write page out, page is locked */ - PAGE_KEEP, - /* move page to the active list, page is locked */ - PAGE_ACTIVATE, - /* page has been sent to the disk successfully, page is unlocked */ - PAGE_SUCCESS, - /* page is clean and locked */ - PAGE_CLEAN, -} pageout_t; +#include "internal.h" struct scan_control { - /* Ask refill_inactive_zone, or shrink_cache to scan this many pages */ - unsigned long nr_to_scan; - /* Incremented by the number of inactive pages that were scanned */ unsigned long nr_scanned; - /* Incremented by the number of pages reclaimed */ - unsigned long nr_reclaimed; - unsigned long nr_mapped; /* From page_state */ - /* How many pages shrink_cache() should reclaim */ - int nr_to_reclaim; - - /* Ask shrink_caches, or shrink_zone to scan at this priority */ - unsigned int priority; - /* This context's GFP mask */ - unsigned int gfp_mask; + gfp_t gfp_mask; int may_writepage; + /* 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 @@ -180,28 +162,43 @@ EXPORT_SYMBOL(remove_shrinker); * `lru_pages' represents the number of on-LRU pages in all the zones which * are eligible for the caller's allocation attempt. It is used for balancing * slab reclaim versus page reclaim. + * + * Returns the number of slab objects which we shrunk. */ -static int shrink_slab(unsigned long scanned, unsigned int gfp_mask, +unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask, unsigned long lru_pages) { struct shrinker *shrinker; + unsigned long ret = 0; if (scanned == 0) scanned = SWAP_CLUSTER_MAX; if (!down_read_trylock(&shrinker_rwsem)) - return 0; + return 1; /* Assume we'll be able to shrink next time */ list_for_each_entry(shrinker, &shrinker_list, list) { unsigned long long delta; unsigned long total_scan; + unsigned long max_pass = (*shrinker->shrinker)(0, gfp_mask); delta = (4 * scanned) / shrinker->seeks; - delta *= (*shrinker->shrinker)(0, gfp_mask); + delta *= max_pass; do_div(delta, lru_pages + 1); shrinker->nr += delta; - if (shrinker->nr < 0) - shrinker->nr = LONG_MAX; /* It wrapped! */ + if (shrinker->nr < 0) { + printk(KERN_ERR "%s: nr=%ld\n", + __FUNCTION__, shrinker->nr); + shrinker->nr = max_pass; + } + + /* + * Avoid risking looping forever due to too large nr value: + * never try to free more than twice the estimate number of + * freeable entries. + */ + if (shrinker->nr > max_pass * 2) + shrinker->nr = max_pass * 2; total_scan = shrinker->nr; shrinker->nr = 0; @@ -209,10 +206,14 @@ static int shrink_slab(unsigned long scanned, unsigned int gfp_mask, while (total_scan >= SHRINK_BATCH) { long this_scan = SHRINK_BATCH; int shrink_ret; + int nr_before; + nr_before = (*shrinker->shrinker)(0, gfp_mask); shrink_ret = (*shrinker->shrinker)(this_scan, gfp_mask); if (shrink_ret == -1) break; + if (shrink_ret < nr_before) + ret += nr_before - shrink_ret; mod_page_state(slabs_scanned, this_scan); total_scan -= this_scan; @@ -222,7 +223,7 @@ static int shrink_slab(unsigned long scanned, unsigned int gfp_mask, shrinker->nr += total_scan; } up_read(&shrinker_rwsem); - return 0; + return ret; } /* Called without lock on whether page is mapped, so answer is unstable */ @@ -253,9 +254,7 @@ static inline int is_page_cache_freeable(struct page *page) static int may_write_to_queue(struct backing_dev_info *bdi) { - if (current_is_kswapd()) - return 1; - if (current_is_pdflush()) /* This is unlikely, but why not... */ + if (current->flags & PF_SWAPWRITE) return 1; if (!bdi_write_congested(bdi)) return 1; @@ -290,9 +289,10 @@ static void handle_write_error(struct address_space *mapping, } /* - * pageout is called by shrink_list() for each dirty page. Calls ->writepage(). + * pageout is called by shrink_page_list() for each dirty page. + * Calls ->writepage(). */ -static pageout_t pageout(struct page *page, struct address_space *mapping) +pageout_t pageout(struct page *page, struct address_space *mapping) { /* * If the page is dirty, only perform writeback if that write @@ -345,7 +345,7 @@ static pageout_t pageout(struct page *page, struct address_space *mapping) res = mapping->a_ops->writepage(page, &wbc); if (res < 0) handle_write_error(mapping, page, res); - if (res == WRITEPAGE_ACTIVATE) { + if (res == AOP_WRITEPAGE_ACTIVATE) { ClearPageReclaim(page); return PAGE_ACTIVATE; } @@ -360,15 +360,53 @@ static pageout_t pageout(struct page *page, struct address_space *mapping) return PAGE_CLEAN; } +int remove_mapping(struct address_space *mapping, struct page *page) +{ + if (!mapping) + return 0; /* truncate got there first */ + + write_lock_irq(&mapping->tree_lock); + + /* + * The non-racy check for busy page. It is critical to check + * PageDirty _after_ making sure that the page is freeable and + * not in use by anybody. (pagecache + us == 2) + */ + if (unlikely(page_count(page) != 2)) + goto cannot_free; + smp_rmb(); + if (unlikely(PageDirty(page))) + goto cannot_free; + + if (PageSwapCache(page)) { + swp_entry_t swap = { .val = page_private(page) }; + __delete_from_swap_cache(page); + write_unlock_irq(&mapping->tree_lock); + swap_free(swap); + __put_page(page); /* The pagecache ref */ + return 1; + } + + __remove_from_page_cache(page); + write_unlock_irq(&mapping->tree_lock); + __put_page(page); + return 1; + +cannot_free: + write_unlock_irq(&mapping->tree_lock); + return 0; +} + /* - * shrink_list adds the number of reclaimed pages to sc->nr_reclaimed + * shrink_page_list() returns the number of reclaimed pages */ -static int shrink_list(struct list_head *page_list, struct scan_control *sc) +static unsigned long shrink_page_list(struct list_head *page_list, + struct scan_control *sc) { LIST_HEAD(ret_pages); struct pagevec freed_pvec; int pgactivate = 0; - int reclaimed = 0; + unsigned long nr_reclaimed = 0; cond_resched(); @@ -390,6 +428,10 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc) BUG_ON(PageActive(page)); sc->nr_scanned++; + + if (!sc->may_swap && page_mapped(page)) + goto keep_locked; + /* Double the slab pressure for mapped and swapcache pages */ if (page_mapped(page) || PageSwapCache(page)) sc->nr_scanned++; @@ -397,7 +439,7 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc) if (PageWriteback(page)) goto keep_locked; - referenced = page_referenced(page, 1, sc->priority <= 0); + referenced = page_referenced(page, 1); /* In active use or really unfreeable? Activate it. */ if (referenced && page_mapping_inuse(page)) goto activate_locked; @@ -407,10 +449,9 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc) * Anonymous process memory has backing store? * Try to allocate it some swap space here. */ - if (PageAnon(page) && !PageSwapCache(page)) { - if (!add_to_swap(page)) + if (PageAnon(page) && !PageSwapCache(page)) + if (!add_to_swap(page, GFP_ATOMIC)) goto activate_locked; - } #endif /* CONFIG_SWAP */ mapping = page_mapping(page); @@ -422,7 +463,7 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc) * processes. Try to unmap it here. */ if (page_mapped(page) && mapping) { - switch (try_to_unmap(page)) { + switch (try_to_unmap(page, 0)) { case SWAP_FAIL: goto activate_locked; case SWAP_AGAIN: @@ -437,7 +478,7 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc) goto keep_locked; if (!may_enter_fs) goto keep_locked; - if (laptop_mode && !sc->may_writepage) + if (!sc->may_writepage) goto keep_locked; /* Page is dirty, try to write it out here */ @@ -491,39 +532,12 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc) goto free_it; } - if (!mapping) - goto keep_locked; /* truncate got there first */ - - write_lock_irq(&mapping->tree_lock); - - /* - * The non-racy check for busy page. It is critical to check - * PageDirty _after_ making sure that the page is freeable and - * not in use by anybody. (pagecache + us == 2) - */ - if (page_count(page) != 2 || PageDirty(page)) { - write_unlock_irq(&mapping->tree_lock); + if (!remove_mapping(mapping, page)) goto keep_locked; - } - -#ifdef CONFIG_SWAP - if (PageSwapCache(page)) { - swp_entry_t swap = { .val = page->private }; - __delete_from_swap_cache(page); - write_unlock_irq(&mapping->tree_lock); - swap_free(swap); - __put_page(page); /* The pagecache ref */ - goto free_it; - } -#endif /* CONFIG_SWAP */ - - __remove_from_page_cache(page); - write_unlock_irq(&mapping->tree_lock); - __put_page(page); free_it: unlock_page(page); - reclaimed++; + nr_reclaimed++; if (!pagevec_add(&freed_pvec, page)) __pagevec_release_nonlru(&freed_pvec); continue; @@ -541,8 +555,7 @@ keep: if (pagevec_count(&freed_pvec)) __pagevec_release_nonlru(&freed_pvec); mod_page_state(pgactivate, pgactivate); - sc->nr_reclaimed += reclaimed; - return reclaimed; + return nr_reclaimed; } /* @@ -562,32 +575,35 @@ keep: * * returns how many pages were moved onto *@dst. */ -static int isolate_lru_pages(int nr_to_scan, struct list_head *src, - struct list_head *dst, int *scanned) +static unsigned long isolate_lru_pages(unsigned long nr_to_scan, + struct list_head *src, struct list_head *dst, + unsigned long *scanned) { - int nr_taken = 0; + unsigned long nr_taken = 0; struct page *page; - int scan = 0; + unsigned long scan; - while (scan++ < nr_to_scan && !list_empty(src)) { + for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) { + struct list_head *target; page = lru_to_page(src); prefetchw_prev_lru_page(page, src, flags); - if (!TestClearPageLRU(page)) - BUG(); + BUG_ON(!PageLRU(page)); + list_del(&page->lru); - if (get_page_testone(page)) { + target = src; + if (likely(get_page_unless_zero(page))) { /* - * It is being freed elsewhere + * Be careful not to clear PageLRU until after we're + * sure the page is not being freed elsewhere -- the + * page release code relies on it. */ - __put_page(page); - SetPageLRU(page); - list_add(&page->lru, src); - continue; - } else { - list_add(&page->lru, dst); + ClearPageLRU(page); + target = dst; nr_taken++; - } + } /* else it is being freed elsewhere */ + + list_add(&page->lru, target); } *scanned = scan; @@ -595,23 +611,26 @@ static int isolate_lru_pages(int nr_to_scan, struct list_head *src, } /* - * shrink_cache() adds the number of pages reclaimed to sc->nr_reclaimed + * shrink_inactive_list() is a helper for shrink_zone(). It returns the number + * of reclaimed pages */ -static void shrink_cache(struct zone *zone, struct scan_control *sc) +static unsigned long shrink_inactive_list(unsigned long max_scan, + struct zone *zone, struct scan_control *sc) { LIST_HEAD(page_list); struct pagevec pvec; - int max_scan = sc->nr_to_scan; + unsigned long nr_scanned = 0; + unsigned long nr_reclaimed = 0; pagevec_init(&pvec, 1); lru_add_drain(); spin_lock_irq(&zone->lru_lock); - while (max_scan > 0) { + do { struct page *page; - int nr_taken; - int nr_scan; - int nr_freed; + unsigned long nr_taken; + unsigned long nr_scan; + unsigned long nr_freed; nr_taken = isolate_lru_pages(sc->swap_cluster_max, &zone->inactive_list, @@ -620,28 +639,28 @@ static void shrink_cache(struct zone *zone, struct scan_control *sc) zone->pages_scanned += nr_scan; spin_unlock_irq(&zone->lru_lock); + nr_scanned += nr_scan; + nr_freed = shrink_page_list(&page_list, sc); + nr_reclaimed += nr_freed; + local_irq_disable(); + if (current_is_kswapd()) { + __mod_page_state_zone(zone, pgscan_kswapd, nr_scan); + __mod_page_state(kswapd_steal, nr_freed); + } else + __mod_page_state_zone(zone, pgscan_direct, nr_scan); + __mod_page_state_zone(zone, pgsteal, nr_freed); + if (nr_taken == 0) goto done; - max_scan -= nr_scan; - if (current_is_kswapd()) - mod_page_state_zone(zone, pgscan_kswapd, nr_scan); - else - mod_page_state_zone(zone, pgscan_direct, nr_scan); - nr_freed = shrink_list(&page_list, sc); - if (current_is_kswapd()) - mod_page_state(kswapd_steal, nr_freed); - mod_page_state_zone(zone, pgsteal, nr_freed); - sc->nr_to_reclaim -= nr_freed; - - spin_lock_irq(&zone->lru_lock); + spin_lock(&zone->lru_lock); /* * Put back any unfreeable pages. */ while (!list_empty(&page_list)) { page = lru_to_page(&page_list); - if (TestSetPageLRU(page)) - BUG(); + BUG_ON(PageLRU(page)); + SetPageLRU(page); list_del(&page->lru); if (PageActive(page)) add_page_to_active_list(zone, page); @@ -653,10 +672,12 @@ static void shrink_cache(struct zone *zone, struct scan_control *sc) spin_lock_irq(&zone->lru_lock); } } - } - spin_unlock_irq(&zone->lru_lock); + } while (nr_scanned < max_scan); + spin_unlock(&zone->lru_lock); done: + local_irq_enable(); pagevec_release(&pvec); + return nr_reclaimed; } /* @@ -676,22 +697,59 @@ done: * The downside is that we have to touch page->_count against each page. * But we had to alter page->flags anyway. */ -static void -refill_inactive_zone(struct zone *zone, struct scan_control *sc) +static void shrink_active_list(unsigned long nr_pages, struct zone *zone, + struct scan_control *sc) { - int pgmoved; + unsigned long pgmoved; int pgdeactivate = 0; - int pgscanned; - int nr_pages = sc->nr_to_scan; + unsigned long pgscanned; LIST_HEAD(l_hold); /* The pages which were snipped off */ LIST_HEAD(l_inactive); /* Pages to go onto the inactive_list */ LIST_HEAD(l_active); /* Pages to go onto the active_list */ struct page *page; struct pagevec pvec; int reclaim_mapped = 0; - long mapped_ratio; - long distress; - long swap_tendency; + + if (sc->may_swap) { + long mapped_ratio; + long distress; + long swap_tendency; + + /* + * `distress' is a measure of how much trouble we're having + * reclaiming pages. 0 -> no problems. 100 -> great trouble. + */ + distress = 100 >> zone->prev_priority; + + /* + * The point of this algorithm is to decide when to start + * reclaiming mapped memory instead of just pagecache. Work out + * how much memory + * is mapped. + */ + mapped_ratio = (sc->nr_mapped * 100) / total_memory; + + /* + * Now decide how much we really want to unmap some pages. The + * mapped ratio is downgraded - just because there's a lot of + * mapped memory doesn't necessarily mean that page reclaim + * isn't succeeding. + * + * The distress ratio is important - we don't want to start + * going oom. + * + * A 100% value of vm_swappiness overrides this algorithm + * altogether. + */ + swap_tendency = mapped_ratio / 2 + distress + vm_swappiness; + + /* + * Now use this metric to decide whether to start moving mapped + * memory onto the inactive list. + */ + if (swap_tendency >= 100) + reclaim_mapped = 1; + } lru_add_drain(); spin_lock_irq(&zone->lru_lock); @@ -701,37 +759,6 @@ refill_inactive_zone(struct zone *zone, struct scan_control *sc) zone->nr_active -= pgmoved; spin_unlock_irq(&zone->lru_lock); - /* - * `distress' is a measure of how much trouble we're having reclaiming - * pages. 0 -> no problems. 100 -> great trouble. - */ - distress = 100 >> zone->prev_priority; - - /* - * The point of this algorithm is to decide when to start reclaiming - * mapped memory instead of just pagecache. Work out how much memory - * is mapped. - */ - mapped_ratio = (sc->nr_mapped * 100) / total_memory; - - /* - * Now decide how much we really want to unmap some pages. The mapped - * ratio is downgraded - just because there's a lot of mapped memory - * doesn't necessarily mean that page reclaim isn't succeeding. - * - * The distress ratio is important - we don't want to start going oom. - * - * A 100% value of vm_swappiness overrides this algorithm altogether. - */ - swap_tendency = mapped_ratio / 2 + distress + vm_swappiness; - - /* - * Now use this metric to decide whether to start moving mapped memory - * onto the inactive list. - */ - if (swap_tendency >= 100) - reclaim_mapped = 1; - while (!list_empty(&l_hold)) { cond_resched(); page = lru_to_page(&l_hold); @@ -739,7 +766,7 @@ refill_inactive_zone(struct zone *zone, struct scan_control *sc) if (page_mapped(page)) { if (!reclaim_mapped || (total_swap_pages == 0 && PageAnon(page)) || - page_referenced(page, 0, sc->priority <= 0)) { + page_referenced(page, 0)) { list_add(&page->lru, &l_active); continue; } @@ -753,10 +780,11 @@ refill_inactive_zone(struct zone *zone, struct scan_control *sc) while (!list_empty(&l_inactive)) { page = lru_to_page(&l_inactive); prefetchw_prev_lru_page(page, &l_inactive, flags); - if (TestSetPageLRU(page)) - BUG(); - if (!TestClearPageActive(page)) - BUG(); + BUG_ON(PageLRU(page)); + SetPageLRU(page); + BUG_ON(!PageActive(page)); + ClearPageActive(page); + list_move(&page->lru, &zone->inactive_list); pgmoved++; if (!pagevec_add(&pvec, page)) { @@ -782,8 +810,8 @@ refill_inactive_zone(struct zone *zone, struct scan_control *sc) while (!list_empty(&l_active)) { page = lru_to_page(&l_active); prefetchw_prev_lru_page(page, &l_active, flags); - if (TestSetPageLRU(page)) - BUG(); + BUG_ON(PageLRU(page)); + SetPageLRU(page); BUG_ON(!PageActive(page)); list_move(&page->lru, &zone->active_list); pgmoved++; @@ -796,61 +824,67 @@ refill_inactive_zone(struct zone *zone, struct scan_control *sc) } } zone->nr_active += pgmoved; - spin_unlock_irq(&zone->lru_lock); - pagevec_release(&pvec); + spin_unlock(&zone->lru_lock); - mod_page_state_zone(zone, pgrefill, pgscanned); - mod_page_state(pgdeactivate, pgdeactivate); + __mod_page_state_zone(zone, pgrefill, pgscanned); + __mod_page_state(pgdeactivate, pgdeactivate); + local_irq_enable(); + + pagevec_release(&pvec); } /* * This is a basic per-zone page freer. Used by both kswapd and direct reclaim. */ -static void -shrink_zone(struct zone *zone, struct scan_control *sc) +static unsigned long shrink_zone(int priority, struct zone *zone, + struct scan_control *sc) { unsigned long nr_active; unsigned long nr_inactive; + unsigned long nr_to_scan; + unsigned long nr_reclaimed = 0; + + atomic_inc(&zone->reclaim_in_progress); /* * Add one to `nr_to_scan' just to make sure that the kernel will * slowly sift through the active list. */ - zone->nr_scan_active += (zone->nr_active >> sc->priority) + 1; + zone->nr_scan_active += (zone->nr_active >> priority) + 1; nr_active = zone->nr_scan_active; if (nr_active >= sc->swap_cluster_max) zone->nr_scan_active = 0; else nr_active = 0; - zone->nr_scan_inactive += (zone->nr_inactive >> sc->priority) + 1; + zone->nr_scan_inactive += (zone->nr_inactive >> priority) + 1; nr_inactive = zone->nr_scan_inactive; if (nr_inactive >= sc->swap_cluster_max) zone->nr_scan_inactive = 0; else nr_inactive = 0; - sc->nr_to_reclaim = sc->swap_cluster_max; - while (nr_active || nr_inactive) { if (nr_active) { - sc->nr_to_scan = min(nr_active, + nr_to_scan = min(nr_active, (unsigned long)sc->swap_cluster_max); - nr_active -= sc->nr_to_scan; - refill_inactive_zone(zone, sc); + nr_active -= nr_to_scan; + shrink_active_list(nr_to_scan, zone, sc); } if (nr_inactive) { - sc->nr_to_scan = min(nr_inactive, + nr_to_scan = min(nr_inactive, (unsigned long)sc->swap_cluster_max); - nr_inactive -= sc->nr_to_scan; - shrink_cache(zone, sc); - if (sc->nr_to_reclaim <= 0) - break; + nr_inactive -= nr_to_scan; + nr_reclaimed += shrink_inactive_list(nr_to_scan, zone, + sc); } } throttle_vm_writeout(); + + atomic_dec(&zone->reclaim_in_progress); + return nr_reclaimed; } /* @@ -869,29 +903,31 @@ shrink_zone(struct zone *zone, struct scan_control *sc) * If a zone is deemed to be full of pinned pages then just give it a light * scan then give up on it. */ -static void -shrink_caches(struct zone **zones, struct scan_control *sc) +static unsigned long shrink_zones(int priority, struct zone **zones, + struct scan_control *sc) { + unsigned long nr_reclaimed = 0; int i; for (i = 0; zones[i] != NULL; i++) { struct zone *zone = zones[i]; - if (zone->present_pages == 0) + if (!populated_zone(zone)) continue; - if (!cpuset_zone_allowed(zone)) + if (!cpuset_zone_allowed(zone, __GFP_HARDWALL)) continue; - zone->temp_priority = sc->priority; - if (zone->prev_priority > sc->priority) - zone->prev_priority = sc->priority; + zone->temp_priority = priority; + if (zone->prev_priority > priority) + zone->prev_priority = priority; - if (zone->all_unreclaimable && sc->priority != DEF_PRIORITY) + if (zone->all_unreclaimable && priority != DEF_PRIORITY) continue; /* Let kswapd poll it */ - shrink_zone(zone, sc); + nr_reclaimed += shrink_zone(priority, zone, sc); } + return nr_reclaimed; } /* @@ -907,26 +943,28 @@ shrink_caches(struct zone **zones, struct scan_control *sc) * holds filesystem locks which prevent writeout this might not work, and the * allocation attempt will fail. */ -int try_to_free_pages(struct zone **zones, - unsigned int gfp_mask, unsigned int order) +unsigned long try_to_free_pages(struct zone **zones, gfp_t gfp_mask) { int priority; int ret = 0; - int total_scanned = 0, total_reclaimed = 0; + unsigned long total_scanned = 0; + unsigned long nr_reclaimed = 0; struct reclaim_state *reclaim_state = current->reclaim_state; - struct scan_control sc; unsigned long lru_pages = 0; int i; - - sc.gfp_mask = gfp_mask; - sc.may_writepage = 0; + struct scan_control sc = { + .gfp_mask = gfp_mask, + .may_writepage = !laptop_mode, + .swap_cluster_max = SWAP_CLUSTER_MAX, + .may_swap = 1, + }; inc_page_state(allocstall); for (i = 0; zones[i] != NULL; i++) { struct zone *zone = zones[i]; - if (!cpuset_zone_allowed(zone)) + if (!cpuset_zone_allowed(zone, __GFP_HARDWALL)) continue; zone->temp_priority = DEF_PRIORITY; @@ -936,18 +974,16 @@ int try_to_free_pages(struct zone **zones, for (priority = DEF_PRIORITY; priority >= 0; priority--) { sc.nr_mapped = read_page_state(nr_mapped); sc.nr_scanned = 0; - sc.nr_reclaimed = 0; - sc.priority = priority; - sc.swap_cluster_max = SWAP_CLUSTER_MAX; - shrink_caches(zones, &sc); + if (!priority) + disable_swap_token(); + nr_reclaimed += shrink_zones(priority, zones, &sc); shrink_slab(sc.nr_scanned, gfp_mask, lru_pages); if (reclaim_state) { - sc.nr_reclaimed += reclaim_state->reclaimed_slab; + nr_reclaimed += reclaim_state->reclaimed_slab; reclaim_state->reclaimed_slab = 0; } total_scanned += sc.nr_scanned; - total_reclaimed += sc.nr_reclaimed; - if (total_reclaimed >= sc.swap_cluster_max) { + if (nr_reclaimed >= sc.swap_cluster_max) { ret = 1; goto out; } @@ -959,8 +995,9 @@ int try_to_free_pages(struct zone **zones, * 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_bdflush(laptop_mode ? 0 : total_scanned); + if (total_scanned > sc.swap_cluster_max + + sc.swap_cluster_max / 2) { + wakeup_pdflush(laptop_mode ? 0 : total_scanned); sc.may_writepage = 1; } @@ -972,7 +1009,7 @@ out: for (i = 0; zones[i] != 0; i++) { struct zone *zone = zones[i]; - if (!cpuset_zone_allowed(zone)) + if (!cpuset_zone_allowed(zone, __GFP_HARDWALL)) continue; zone->prev_priority = zone->temp_priority; @@ -1005,21 +1042,26 @@ out: * the page allocator fallback scheme to ensure that aging of pages is balanced * across the zones. */ -static int balance_pgdat(pg_data_t *pgdat, int nr_pages, int order) +static unsigned long balance_pgdat(pg_data_t *pgdat, unsigned long nr_pages, + int order) { - int to_free = nr_pages; + unsigned long to_free = nr_pages; int all_zones_ok; int priority; int i; - int total_scanned, total_reclaimed; + unsigned long total_scanned; + unsigned long nr_reclaimed; struct reclaim_state *reclaim_state = current->reclaim_state; - struct scan_control sc; + struct scan_control sc = { + .gfp_mask = GFP_KERNEL, + .may_swap = 1, + .swap_cluster_max = nr_pages ? nr_pages : SWAP_CLUSTER_MAX, + }; loop_again: total_scanned = 0; - total_reclaimed = 0; - sc.gfp_mask = GFP_KERNEL; - sc.may_writepage = 0; + nr_reclaimed = 0; + sc.may_writepage = !laptop_mode; sc.nr_mapped = read_page_state(nr_mapped); inc_page_state(pageoutrun); @@ -1034,6 +1076,10 @@ loop_again: int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */ unsigned long lru_pages = 0; + /* The swap token gets in the way of swapout... */ + if (!priority) + disable_swap_token(); + all_zones_ok = 1; if (nr_pages == 0) { @@ -1044,7 +1090,7 @@ loop_again: for (i = pgdat->nr_zones - 1; i >= 0; i--) { struct zone *zone = pgdat->node_zones + i; - if (zone->present_pages == 0) + if (!populated_zone(zone)) continue; if (zone->all_unreclaimable && @@ -1052,7 +1098,7 @@ loop_again: continue; if (!zone_watermark_ok(zone, order, - zone->pages_high, 0, 0, 0)) { + zone->pages_high, 0, 0)) { end_zone = i; goto scan; } @@ -1079,8 +1125,9 @@ scan: */ for (i = 0; i <= end_zone; i++) { struct zone *zone = pgdat->node_zones + i; + int nr_slab; - if (zone->present_pages == 0) + if (!populated_zone(zone)) continue; if (zone->all_unreclaimable && priority != DEF_PRIORITY) @@ -1088,26 +1135,23 @@ scan: if (nr_pages == 0) { /* Not software suspend */ if (!zone_watermark_ok(zone, order, - zone->pages_high, end_zone, 0, 0)) + zone->pages_high, end_zone, 0)) all_zones_ok = 0; } zone->temp_priority = priority; if (zone->prev_priority > priority) zone->prev_priority = priority; sc.nr_scanned = 0; - sc.nr_reclaimed = 0; - sc.priority = priority; - sc.swap_cluster_max = nr_pages? nr_pages : SWAP_CLUSTER_MAX; - shrink_zone(zone, &sc); + nr_reclaimed += shrink_zone(priority, zone, &sc); reclaim_state->reclaimed_slab = 0; - shrink_slab(sc.nr_scanned, GFP_KERNEL, lru_pages); - sc.nr_reclaimed += reclaim_state->reclaimed_slab; - total_reclaimed += sc.nr_reclaimed; + nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL, + lru_pages); + nr_reclaimed += reclaim_state->reclaimed_slab; total_scanned += sc.nr_scanned; if (zone->all_unreclaimable) continue; - if (zone->pages_scanned >= (zone->nr_active + - zone->nr_inactive) * 4) + if (nr_slab == 0 && zone->pages_scanned >= + (zone->nr_active + zone->nr_inactive) * 4) zone->all_unreclaimable = 1; /* * If we've done a decent amount of scanning and @@ -1115,10 +1159,10 @@ scan: * even in laptop mode */ if (total_scanned > SWAP_CLUSTER_MAX * 2 && - total_scanned > total_reclaimed+total_reclaimed/2) + total_scanned > nr_reclaimed + nr_reclaimed / 2) sc.may_writepage = 1; } - if (nr_pages && to_free > total_reclaimed) + if (nr_pages && to_free > nr_reclaimed) continue; /* swsusp: need to do more work */ if (all_zones_ok) break; /* kswapd: all done */ @@ -1135,7 +1179,7 @@ scan: * matches the direct reclaim path behaviour in terms of impact * on zone->*_priority. */ - if ((total_reclaimed >= SWAP_CLUSTER_MAX) && (!nr_pages)) + if ((nr_reclaimed >= SWAP_CLUSTER_MAX) && !nr_pages) break; } out: @@ -1149,7 +1193,7 @@ out: goto loop_again; } - return total_reclaimed; + return nr_reclaimed; } /* @@ -1194,13 +1238,13 @@ static int kswapd(void *p) * us from recursively trying to free more memory as we're * trying to free the first piece of memory in the first place). */ - tsk->flags |= PF_MEMALLOC|PF_KSWAPD; + tsk->flags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD; order = 0; for ( ; ; ) { unsigned long new_order; - if (current->flags & PF_FREEZE) - refrigerator(PF_FREEZE); + + try_to_freeze(); prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); new_order = pgdat->kswapd_max_order; @@ -1229,19 +1273,19 @@ void wakeup_kswapd(struct zone *zone, int order) { pg_data_t *pgdat; - if (zone->present_pages == 0) + if (!populated_zone(zone)) return; pgdat = zone->zone_pgdat; - if (zone_watermark_ok(zone, order, zone->pages_low, 0, 0, 0)) + if (zone_watermark_ok(zone, order, zone->pages_low, 0, 0)) return; if (pgdat->kswapd_max_order < order) pgdat->kswapd_max_order = order; - if (!cpuset_zone_allowed(zone)) + if (!cpuset_zone_allowed(zone, __GFP_HARDWALL)) return; - if (!waitqueue_active(&zone->zone_pgdat->kswapd_wait)) + if (!waitqueue_active(&pgdat->kswapd_wait)) return; - wake_up_interruptible(&zone->zone_pgdat->kswapd_wait); + wake_up_interruptible(&pgdat->kswapd_wait); } #ifdef CONFIG_PM @@ -1249,24 +1293,31 @@ void wakeup_kswapd(struct zone *zone, int order) * Try to free `nr_pages' of memory, system-wide. Returns the number of freed * pages. */ -int shrink_all_memory(int nr_pages) +unsigned long shrink_all_memory(unsigned long nr_pages) { pg_data_t *pgdat; - int nr_to_free = nr_pages; - int ret = 0; + unsigned long nr_to_free = nr_pages; + unsigned long ret = 0; + unsigned retry = 2; struct reclaim_state reclaim_state = { .reclaimed_slab = 0, }; current->reclaim_state = &reclaim_state; - for_each_pgdat(pgdat) { - int freed; +repeat: + for_each_online_pgdat(pgdat) { + unsigned long freed; + freed = balance_pgdat(pgdat, nr_to_free, 0); ret += freed; nr_to_free -= freed; - if (nr_to_free <= 0) + if ((long)nr_to_free <= 0) break; } + if (retry-- && ret < nr_pages) { + blk_congestion_wait(WRITE, HZ/5); + goto repeat; + } current->reclaim_state = NULL; return ret; } @@ -1277,15 +1328,14 @@ int shrink_all_memory(int nr_pages) not required for correctness. So if the last cpu in a node goes away, we get changed to run anywhere: as the first one comes back, restore their cpu bindings. */ -static int __devinit cpu_callback(struct notifier_block *nfb, - unsigned long action, - void *hcpu) +static int cpu_callback(struct notifier_block *nfb, + unsigned long action, void *hcpu) { pg_data_t *pgdat; cpumask_t mask; if (action == CPU_ONLINE) { - for_each_pgdat(pgdat) { + for_each_online_pgdat(pgdat) { mask = node_to_cpumask(pgdat->node_id); if (any_online_cpu(mask) != NR_CPUS) /* One of our CPUs online: restore mask */ @@ -1299,13 +1349,162 @@ static int __devinit cpu_callback(struct notifier_block *nfb, static int __init kswapd_init(void) { pg_data_t *pgdat; + swap_setup(); - for_each_pgdat(pgdat) - pgdat->kswapd - = find_task_by_real_pid(kernel_thread(kswapd, pgdat, CLONE_KERNEL)); + for_each_online_pgdat(pgdat) { + pid_t pid; + + pid = kernel_thread(kswapd, pgdat, CLONE_KERNEL); + BUG_ON(pid < 0); + read_lock(&tasklist_lock); + pgdat->kswapd = find_task_by_real_pid(pid); + read_unlock(&tasklist_lock); + } total_memory = nr_free_pagecache_pages(); hotcpu_notifier(cpu_callback, 0); return 0; } module_init(kswapd_init) + +#ifdef CONFIG_NUMA +/* + * Zone reclaim mode + * + * If non-zero call zone_reclaim when the number of free pages falls below + * the watermarks. + * + * In the future we may add flags to the mode. However, the page allocator + * should only have to check that zone_reclaim_mode != 0 before calling + * zone_reclaim(). + */ +int zone_reclaim_mode __read_mostly; + +#define RECLAIM_OFF 0 +#define RECLAIM_ZONE (1<<0) /* Run shrink_cache on the zone */ +#define RECLAIM_WRITE (1<<1) /* Writeout pages during reclaim */ +#define RECLAIM_SWAP (1<<2) /* Swap pages out during reclaim */ +#define RECLAIM_SLAB (1<<3) /* Do a global slab shrink if the zone is out of memory */ + +/* + * Mininum time between zone reclaim scans + */ +int zone_reclaim_interval __read_mostly = 30*HZ; + +/* + * Priority for ZONE_RECLAIM. This determines the fraction of pages + * of a node considered for each zone_reclaim. 4 scans 1/16th of + * a zone. + */ +#define ZONE_RECLAIM_PRIORITY 4 + +/* + * Try to free up some pages from this zone through reclaim. + */ +static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) +{ + /* Minimum pages needed in order to stay on node */ + const unsigned long nr_pages = 1 << order; + struct task_struct *p = current; + struct reclaim_state reclaim_state; + int priority; + unsigned long nr_reclaimed = 0; + struct scan_control sc = { + .may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE), + .may_swap = !!(zone_reclaim_mode & RECLAIM_SWAP), + .nr_mapped = read_page_state(nr_mapped), + .swap_cluster_max = max_t(unsigned long, nr_pages, + SWAP_CLUSTER_MAX), + .gfp_mask = gfp_mask, + }; + + disable_swap_token(); + cond_resched(); + /* + * We need to be able to allocate from the reserves for RECLAIM_SWAP + * and we also need to be able to write out pages for RECLAIM_WRITE + * and RECLAIM_SWAP. + */ + p->flags |= PF_MEMALLOC | PF_SWAPWRITE; + reclaim_state.reclaimed_slab = 0; + p->reclaim_state = &reclaim_state; + + /* + * Free memory by calling shrink zone with increasing priorities + * until we have enough memory freed. + */ + priority = ZONE_RECLAIM_PRIORITY; + do { + nr_reclaimed += shrink_zone(priority, zone, &sc); + priority--; + } while (priority >= 0 && nr_reclaimed < nr_pages); + + if (nr_reclaimed < nr_pages && (zone_reclaim_mode & RECLAIM_SLAB)) { + /* + * shrink_slab() does not currently allow us to determine how + * many pages were freed in this zone. So we just shake the slab + * a bit and then go off node for this particular allocation + * despite possibly having freed enough memory to allocate in + * this zone. If we freed local memory then the next + * allocations will be local again. + * + * shrink_slab will free memory on all zones and may take + * a long time. + */ + shrink_slab(sc.nr_scanned, gfp_mask, order); + } + + p->reclaim_state = NULL; + current->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE); + + if (nr_reclaimed == 0) { + /* + * We were unable to reclaim enough pages to stay on node. We + * now allow off node accesses for a certain time period before + * trying again to reclaim pages from the local zone. + */ + zone->last_unsuccessful_zone_reclaim = jiffies; + } + + return nr_reclaimed >= nr_pages; +} + +int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) +{ + cpumask_t mask; + int node_id; + + /* + * Do not reclaim if there was a recent unsuccessful attempt at zone + * reclaim. In that case we let allocations go off node for the + * zone_reclaim_interval. Otherwise we would scan for each off-node + * page allocation. + */ + if (time_before(jiffies, + zone->last_unsuccessful_zone_reclaim + zone_reclaim_interval)) + return 0; + + /* + * Avoid concurrent zone reclaims, do not reclaim in a zone that does + * not have reclaimable pages and if we should not delay the allocation + * then do not scan. + */ + if (!(gfp_mask & __GFP_WAIT) || + zone->all_unreclaimable || + atomic_read(&zone->reclaim_in_progress) > 0 || + (current->flags & PF_MEMALLOC)) + return 0; + + /* + * Only run zone reclaim on the local zone or on zones that do not + * have associated processors. This will favor the local processor + * over remote processors and spread off node memory allocations + * as wide as possible. + */ + node_id = zone->zone_pgdat->node_id; + mask = node_to_cpumask(node_id); + if (!cpus_empty(mask) && node_id != numa_node_id()) + return 0; + return __zone_reclaim(zone, gfp_mask, order); +} +#endif