vmscan: stop kswapd waiting on congestion when the min watermark is not being met
If reclaim fails to make sufficient progress, the priority is raised.
Once the priority is higher, kswapd starts waiting on congestion.
However, if the zone is below the min watermark then kswapd needs to
continue working without delay as there is a danger of an increased rate
of GFP_ATOMIC allocation failure.
This patch changes the conditions under which kswapd waits on congestion
by only going to sleep if the min watermarks are being met.
[[email protected]: add stats to track how relevant the logic is]
[[email protected]: make kswapd only check its own zones and rename the relevant counters]
Signed-off-by: KOSAKI Motohiro <[email protected]>
Signed-off-by: Mel Gorman <[email protected]>
Reviewed-by: Rik van Riel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index fd5be24..ee03bba 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -40,7 +40,8 @@
PGSCAN_ZONE_RECLAIM_FAILED,
#endif
PGINODESTEAL, SLABS_SCANNED, KSWAPD_STEAL, KSWAPD_INODESTEAL,
- KSWAPD_PREMATURE_FAST, KSWAPD_PREMATURE_SLOW,
+ KSWAPD_LOW_WMARK_HIT_QUICKLY, KSWAPD_HIGH_WMARK_HIT_QUICKLY,
+ KSWAPD_SKIP_CONGESTION_WAIT,
PAGEOUTRUN, ALLOCSTALL, PGROTATED,
#ifdef CONFIG_HUGETLB_PAGE
HTLB_BUDDY_PGALLOC, HTLB_BUDDY_PGALLOC_FAIL,
