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/compaction.c | 25 +++---------------------- 1 file changed, 3 insertions(+), 22 deletions(-) (limited to 'mm/compaction.c') diff --git a/mm/compaction.c b/mm/compaction.c index 0409a4ad6ea1..70e6bec46dc2 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -634,22 +634,6 @@ isolate_freepages_range(struct compact_control *cc, return pfn; } -/* Update the number of anon and file isolated pages in the zone */ -static void acct_isolated(struct zone *zone, struct compact_control *cc) -{ - struct page *page; - unsigned int count[2] = { 0, }; - - if (list_empty(&cc->migratepages)) - return; - - list_for_each_entry(page, &cc->migratepages, lru) - count[!!page_is_file_cache(page)]++; - - mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_ANON, count[0]); - mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE, count[1]); -} - /* Similar to reclaim, but different enough that they don't share logic */ static bool too_many_isolated(struct zone *zone) { @@ -866,6 +850,8 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, /* Successfully isolated */ del_page_from_lru_list(page, lruvec, page_lru(page)); + inc_node_page_state(page, + NR_ISOLATED_ANON + page_is_file_cache(page)); isolate_success: list_add(&page->lru, &cc->migratepages); @@ -902,7 +888,6 @@ isolate_fail: spin_unlock_irqrestore(zone_lru_lock(zone), flags); locked = false; } - acct_isolated(zone, cc); putback_movable_pages(&cc->migratepages); cc->nr_migratepages = 0; cc->last_migrated_pfn = 0; @@ -988,7 +973,6 @@ isolate_migratepages_range(struct compact_control *cc, unsigned long start_pfn, if (cc->nr_migratepages == COMPACT_CLUSTER_MAX) break; } - acct_isolated(cc->zone, cc); return pfn; } @@ -1258,10 +1242,8 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, low_pfn = isolate_migratepages_block(cc, low_pfn, block_end_pfn, isolate_mode); - if (!low_pfn || cc->contended) { - acct_isolated(zone, cc); + if (!low_pfn || cc->contended) return ISOLATE_ABORT; - } /* * Either we isolated something and proceed with migration. Or @@ -1271,7 +1253,6 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, break; } - acct_isolated(zone, cc); /* Record where migration scanner will be restarted. */ cc->migrate_pfn = low_pfn; -- cgit v1.2.3-59-g8ed1b