diff options
| author | Mel Gorman <mgorman@techsingularity.net> | 2016-07-28 15:47:37 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-07-28 16:07:41 -0700 |
| commit | d7f05528eedb047efe2288cff777676b028747b6 (patch) | |
| tree | dab403a296f8a7ab6bdf2a6a28cad43fdaaddd5f /mm/vmscan.c | |
| parent | f8d1a31163fcb3bf93f6c78770c3c1915f065bf9 (diff) | |
mm, vmscan: account for skipped pages as a partial scan
Page reclaim determines whether a pgdat is unreclaimable by examining
how many pages have been scanned since a page was freed and comparing
that to the LRU sizes. Skipped pages are not reclaim candidates but
contribute to scanned. This can prematurely mark a pgdat as
unreclaimable and trigger an OOM kill.
This patch accounts for skipped pages as a partial scan so that an
unreclaimable pgdat will still be marked as such but by scaling the cost
of a skip, it'll avoid the pgdat being marked prematurely.
Link: http://lkml.kernel.org/r/1469110261-7365-6-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index f7b958b9aea9..0294ab34f475 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1424,7 +1424,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, LIST_HEAD(pages_skipped); for (scan = 0; scan < nr_to_scan && nr_taken < nr_to_scan && - !list_empty(src); scan++) { + !list_empty(src);) { struct page *page; page = lru_to_page(src); @@ -1438,6 +1438,12 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, continue; } + /* + * Account for scanned and skipped separetly to avoid the pgdat + * being prematurely marked unreclaimable by pgdat_reclaimable. + */ + scan++; + switch (__isolate_lru_page(page, mode)) { case 0: nr_pages = hpage_nr_pages(page); @@ -1465,14 +1471,24 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, */ if (!list_empty(&pages_skipped)) { int zid; + unsigned long total_skipped = 0; - list_splice(&pages_skipped, src); for (zid = 0; zid < MAX_NR_ZONES; zid++) { if (!nr_skipped[zid]) continue; __count_zid_vm_events(PGSCAN_SKIP, zid, nr_skipped[zid]); + total_skipped += nr_skipped[zid]; } + + /* + * Account skipped pages as a partial scan as the pgdat may be + * close to unreclaimable. If the LRU list is empty, account + * skipped pages as a full scan. + */ + scan += list_empty(src) ? total_skipped : total_skipped >> 2; + + list_splice(&pages_skipped, src); } *nr_scanned = scan; trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan, scan, |