diff options
| -rw-r--r-- | mm/memcontrol.c | 109 |
1 files changed, 16 insertions, 93 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 71bac4d720d7..d58bb5fa4403 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1137,86 +1137,6 @@ struct lruvec *mem_cgroup_lru_move_lists(struct zone *zone, } /* - * At handling SwapCache and other FUSE stuff, pc->mem_cgroup may be changed - * while it's linked to lru because the page may be reused after it's fully - * uncharged. To handle that, unlink page_cgroup from LRU when charge it again. - * It's done under lock_page and expected that zone->lru_lock isnever held. - */ -static void mem_cgroup_lru_del_before_commit(struct page *page) -{ - enum lru_list lru; - unsigned long flags; - struct zone *zone = page_zone(page); - struct page_cgroup *pc = lookup_page_cgroup(page); - - /* - * Doing this check without taking ->lru_lock seems wrong but this - * is safe. Because if page_cgroup's USED bit is unset, the page - * will not be added to any memcg's LRU. If page_cgroup's USED bit is - * set, the commit after this will fail, anyway. - * This all charge/uncharge is done under some mutual execustion. - * So, we don't need to taking care of changes in USED bit. - */ - if (likely(!PageLRU(page))) - return; - - spin_lock_irqsave(&zone->lru_lock, flags); - lru = page_lru(page); - /* - * The uncharged page could still be registered to the LRU of - * the stale pc->mem_cgroup. - * - * As pc->mem_cgroup is about to get overwritten, the old LRU - * accounting needs to be taken care of. Let root_mem_cgroup - * babysit the page until the new memcg is responsible for it. - * - * The PCG_USED bit is guarded by lock_page() as the page is - * swapcache/pagecache. - */ - if (PageLRU(page) && PageCgroupAcctLRU(pc) && !PageCgroupUsed(pc)) { - del_page_from_lru_list(zone, page, lru); - add_page_to_lru_list(zone, page, lru); - } - spin_unlock_irqrestore(&zone->lru_lock, flags); -} - -static void mem_cgroup_lru_add_after_commit(struct page *page) -{ - enum lru_list lru; - unsigned long flags; - struct zone *zone = page_zone(page); - struct page_cgroup *pc = lookup_page_cgroup(page); - /* - * putback: charge: - * SetPageLRU SetPageCgroupUsed - * smp_mb smp_mb - * PageCgroupUsed && add to memcg LRU PageLRU && add to memcg LRU - * - * Ensure that one of the two sides adds the page to the memcg - * LRU during a race. - */ - smp_mb(); - /* taking care of that the page is added to LRU while we commit it */ - if (likely(!PageLRU(page))) - return; - spin_lock_irqsave(&zone->lru_lock, flags); - lru = page_lru(page); - /* - * If the page is not on the LRU, someone will soon put it - * there. If it is, and also already accounted for on the - * memcg-side, it must be on the right lruvec as setting - * pc->mem_cgroup and PageCgroupUsed is properly ordered. - * Otherwise, root_mem_cgroup has been babysitting the page - * during the charge. Move it to the new memcg now. - */ - if (PageLRU(page) && !PageCgroupAcctLRU(pc)) { - del_page_from_lru_list(zone, page, lru); - add_page_to_lru_list(zone, page, lru); - } - spin_unlock_irqrestore(&zone->lru_lock, flags); -} - -/* * Checks whether given mem is same or in the root_mem_cgroup's * hierarchy subtree */ @@ -2775,14 +2695,27 @@ __mem_cgroup_commit_charge_lrucare(struct page *page, struct mem_cgroup *memcg, enum charge_type ctype) { struct page_cgroup *pc = lookup_page_cgroup(page); + struct zone *zone = page_zone(page); + unsigned long flags; + bool removed = false; + /* * In some case, SwapCache, FUSE(splice_buf->radixtree), the page * is already on LRU. It means the page may on some other page_cgroup's * LRU. Take care of it. */ - mem_cgroup_lru_del_before_commit(page); + spin_lock_irqsave(&zone->lru_lock, flags); + if (PageLRU(page)) { + del_page_from_lru_list(zone, page, page_lru(page)); + ClearPageLRU(page); + removed = true; + } __mem_cgroup_commit_charge(memcg, page, 1, pc, ctype); - mem_cgroup_lru_add_after_commit(page); + if (removed) { + add_page_to_lru_list(zone, page, page_lru(page)); + SetPageLRU(page); + } + spin_unlock_irqrestore(&zone->lru_lock, flags); return; } @@ -3383,9 +3316,7 @@ void mem_cgroup_replace_page_cache(struct page *oldpage, { struct mem_cgroup *memcg; struct page_cgroup *pc; - struct zone *zone; enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE; - unsigned long flags; if (mem_cgroup_disabled()) return; @@ -3401,20 +3332,12 @@ void mem_cgroup_replace_page_cache(struct page *oldpage, if (PageSwapBacked(oldpage)) type = MEM_CGROUP_CHARGE_TYPE_SHMEM; - zone = page_zone(newpage); - pc = lookup_page_cgroup(newpage); /* * Even if newpage->mapping was NULL before starting replacement, * the newpage may be on LRU(or pagevec for LRU) already. We lock * LRU while we overwrite pc->mem_cgroup. */ - spin_lock_irqsave(&zone->lru_lock, flags); - if (PageLRU(newpage)) - del_page_from_lru_list(zone, newpage, page_lru(newpage)); - __mem_cgroup_commit_charge(memcg, newpage, 1, pc, type); - if (PageLRU(newpage)) - add_page_to_lru_list(zone, newpage, page_lru(newpage)); - spin_unlock_irqrestore(&zone->lru_lock, flags); + __mem_cgroup_commit_charge_lrucare(newpage, memcg, type); } #ifdef CONFIG_DEBUG_VM |
