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| author | Mel Gorman <mgorman@suse.de> | 2013-07-08 16:00:25 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-07-09 10:33:23 -0700 |
| commit | 918fc718c5922520c499ad60f61b8df86b998ae9 (patch) | |
| tree | 71c492881b0bcadcdd1a35e63f09cb6df59c86cd /mm/vmscan.c | |
| parent | 5a1c9cbc1550f93335d7c03eb6c271e642deff04 (diff) | |
| download | linux-918fc718c5922520c499ad60f61b8df86b998ae9.tar.gz linux-918fc718c5922520c499ad60f61b8df86b998ae9.tar.bz2 linux-918fc718c5922520c499ad60f61b8df86b998ae9.zip | |
mm: vmscan: do not scale writeback pages when deciding whether to set ZONE_WRITEBACK
After the patch "mm: vmscan: Flatten kswapd priority loop" was merged
the scanning priority of kswapd changed.
The priority now rises until it is scanning enough pages to meet the
high watermark. shrink_inactive_list sets ZONE_WRITEBACK if a number of
pages were encountered under writeback but this value is scaled based on
the priority. As kswapd frequently scans with a higher priority now it
is relatively easy to set ZONE_WRITEBACK. This patch removes the
scaling and treates writeback pages similar to how it treats unqueued
dirty pages and congested pages. The user-visible effect should be that
kswapd will writeback fewer pages from reclaim context.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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 | 16 |
1 files changed, 1 insertions, 15 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 2385663ae5e5..2cff0d491c6d 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1443,25 +1443,11 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, * as there is no guarantee the dirtying process is throttled in the * same way balance_dirty_pages() manages. * - * This scales the number of dirty pages that must be under writeback - * before a zone gets flagged ZONE_WRITEBACK. It is a simple backoff - * function that has the most effect in the range DEF_PRIORITY to - * DEF_PRIORITY-2 which is the priority reclaim is considered to be - * in trouble and reclaim is considered to be in trouble. - * - * DEF_PRIORITY 100% isolated pages must be PageWriteback to throttle - * DEF_PRIORITY-1 50% must be PageWriteback - * DEF_PRIORITY-2 25% must be PageWriteback, kswapd in trouble - * ... - * DEF_PRIORITY-6 For SWAP_CLUSTER_MAX isolated pages, throttle if any - * isolated page is PageWriteback - * * Once a zone is flagged ZONE_WRITEBACK, kswapd will count the number * of pages under pages flagged for immediate reclaim and stall if any * are encountered in the nr_immediate check below. */ - if (nr_writeback && nr_writeback >= - (nr_taken >> (DEF_PRIORITY - sc->priority))) + if (nr_writeback && nr_writeback == nr_taken) zone_set_flag(zone, ZONE_WRITEBACK); /* |