diff options
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 149 |
1 files changed, 136 insertions, 13 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index a8347b6..154b9b6 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 |