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authorWonhyuk Yang <vvghjk1234@gmail.com>2021-06-30 18:50:53 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-06-30 20:47:29 -0700
commitb55ca5264b0c0092f238e2f4f33319ba6e9901ab (patch)
treec283b90b3f5f0a4c3fce6e51ed263fd7b0e076c3 /mm/compaction.c
parentd2155fe54ddb6e289b4f7854df5a7d828d6efbb5 (diff)
mm/compaction: fix 'limit' in fast_isolate_freepages
Because of 'min(1, ...)', fast_isolate_freepages set 'limit' to 0 or 1. This takes away the opportunities of find candinate pages. So, by making enough scans available, increases the probability of finding the appropriate freepage. Tested it on the thpscale and the results are as follows. 5.12.0 5.12.0 valnilla patched Amean fault-both-1 598.15 ( 0.00%) 592.56 ( 0.93%) Amean fault-both-3 1494.47 ( 0.00%) 1514.35 ( -1.33%) Amean fault-both-5 2519.48 ( 0.00%) 2471.76 ( 1.89%) Amean fault-both-7 3173.85 ( 0.00%) 3079.19 ( 2.98%) Amean fault-both-12 8063.83 ( 0.00%) 7858.29 ( 2.55%) Amean fault-both-18 8781.20 ( 0.00%) 7827.70 * 10.86%* Amean fault-both-24 12576.44 ( 0.00%) 12250.20 ( 2.59%) Amean fault-both-30 18503.27 ( 0.00%) 17528.11 * 5.27%* Amean fault-both-32 16133.69 ( 0.00%) 13874.24 * 14.00%* 5.12.0 5.12.0 vanilla patched Ops Compaction migrate scanned 6547133.00 5963901.00 Ops Compaction free scanned 32452453.00 26609101.00 5.12 5.12 vanilla patched Duration User 27.99 28.84 Duration System 244.08 236.76 Duration Elapsed 78.27 78.38 Link: https://lkml.kernel.org/r/20210626082443.22547-1-vvghjk1234@gmail.com Fixes: 5a811889de10f ("mm, compaction: use free lists to quickly locate a migration target") Signed-off-by: Wonhyuk Yang <vvghjk1234@gmail.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> 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/compaction.c')
-rw-r--r--mm/compaction.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/compaction.c b/mm/compaction.c
index f27ea22f297a..4796c197295f 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1378,7 +1378,7 @@ static int next_search_order(struct compact_control *cc, int order)
static unsigned long
fast_isolate_freepages(struct compact_control *cc)
{
- unsigned int limit = min(1U, freelist_scan_limit(cc) >> 1);
+ unsigned int limit = max(1U, freelist_scan_limit(cc) >> 1);
unsigned int nr_scanned = 0;
unsigned long low_pfn, min_pfn, highest = 0;
unsigned long nr_isolated = 0;
@@ -1490,11 +1490,11 @@ fast_isolate_freepages(struct compact_control *cc)
spin_unlock_irqrestore(&cc->zone->lock, flags);
/*
- * Smaller scan on next order so the total scan ig related
+ * Smaller scan on next order so the total scan is related
* to freelist_scan_limit.
*/
if (order_scanned >= limit)
- limit = min(1U, limit >> 1);
+ limit = max(1U, limit >> 1);
}
if (!page) {