From 6afcf8ef0ca0a69d014f8edb613d94821f0ae700 Mon Sep 17 00:00:00 2001 From: Ming Ling Date: Mon, 12 Dec 2016 16:42:26 -0800 Subject: mm, compaction: fix NR_ISOLATED_* stats for pfn based migration Since commit bda807d44454 ("mm: migrate: support non-lru movable page migration") isolate_migratepages_block) can isolate !PageLRU pages which would acct_isolated account as NR_ISOLATED_*. Accounting these non-lru pages NR_ISOLATED_{ANON,FILE} doesn't make any sense and it can misguide heuristics based on those counters such as pgdat_reclaimable_pages resp. too_many_isolated which would lead to unexpected stalls during the direct reclaim without any good reason. Note that __alloc_contig_migrate_range can isolate a lot of pages at once. On mobile devices such as 512M ram android Phone, it may use a big zram swap. In some cases zram(zsmalloc) uses too many non-lru but migratedable pages, such as: MemTotal: 468148 kB Normal free:5620kB Free swap:4736kB Total swap:409596kB ZRAM: 164616kB(zsmalloc non-lru pages) active_anon:60700kB inactive_anon:60744kB active_file:34420kB inactive_file:37532kB Fix this by only accounting lru pages to NR_ISOLATED_* in isolate_migratepages_block right after they were isolated and we still know they were on LRU. Drop acct_isolated because it is called after the fact and we've lost that information. Batching per-cpu counter doesn't make much improvement anyway. Also make sure that we uncharge only LRU pages when putting them back on the LRU in putback_movable_pages resp. when unmap_and_move migrates the page. [mhocko@suse.com: replace acct_isolated() with direct counting] Fixes: bda807d44454 ("mm: migrate: support non-lru movable page migration") Link: http://lkml.kernel.org/r/20161019080240.9682-1-mhocko@kernel.org Signed-off-by: Ming Ling Signed-off-by: Michal Hocko Acked-by: Minchan Kim Acked-by: Vlastimil Babka Cc: Mel Gorman Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/migrate.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 99250aee1ac1..66ce6b490b13 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -168,8 +168,6 @@ void putback_movable_pages(struct list_head *l) continue; } list_del(&page->lru); - dec_node_page_state(page, NR_ISOLATED_ANON + - page_is_file_cache(page)); /* * We isolated non-lru movable page so here we can use * __PageMovable because LRU page's mapping cannot have @@ -186,6 +184,8 @@ void putback_movable_pages(struct list_head *l) put_page(page); } else { putback_lru_page(page); + dec_node_page_state(page, NR_ISOLATED_ANON + + page_is_file_cache(page)); } } } @@ -1121,8 +1121,15 @@ out: * restored. */ list_del(&page->lru); - dec_node_page_state(page, NR_ISOLATED_ANON + - page_is_file_cache(page)); + + /* + * Compaction can migrate also non-LRU pages which are + * not accounted to NR_ISOLATED_*. They can be recognized + * as __PageMovable + */ + if (likely(!__PageMovable(page))) + dec_node_page_state(page, NR_ISOLATED_ANON + + page_is_file_cache(page)); } /* -- cgit