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| author |   Mel Gorman <mgorman@techsingularity.net> | 2019-03-05 15:45:38 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2019-03-05 21:07:17 -0800 |
| commit | e332f741a8dd1ec9a6dc8aa997296ecbfe64323e (patch) | |
| tree | b336a96e0c0073222608d70f4e029d259bfd8691 /include/linux/mmzone.h | |
| parent | mm, compaction: sample pageblocks for free pages (diff) | |
| download | linux-dev-e332f741a8dd1ec9a6dc8aa997296ecbfe64323e.tar.xz linux-dev-e332f741a8dd1ec9a6dc8aa997296ecbfe64323e.zip | |
mm, compaction: be selective about what pageblocks to clear skip hints
Pageblock hints are cleared when compaction restarts or kswapd makes
enough progress that it can sleep but it's over-eager in that the bit is
cleared for migration sources with no LRU pages and migration targets
with no free pages. As pageblock skip hint flushes are relatively rare
and out-of-band with respect to kswapd, this patch makes a few more
expensive checks to see if it's appropriate to even clear the bit.
Every pageblock that is not cleared will avoid 512 pages being scanned
unnecessarily on x86-64.
The impact is variable with different workloads showing small
differences in latency, success rates and scan rates. This is expected
as clearing the hints is not that common but doing a small amount of
work out-of-band to avoid a large amount of work in-band later is
generally a good thing.
Link: http://lkml.kernel.org/r/20190118175136.31341-22-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Qian Cai <cai@lca.pw>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: YueHaibing <yuehaibing@huawei.com>
[cai@lca.pw: no stuck in __reset_isolation_pfn()]
Link: http://lkml.kernel.org/r/20190206034732.75687-1-cai@lca.pw
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/mmzone.h')
| -rw-r--r-- | include/linux/mmzone.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 842f9189537b..90c13cdeefb5 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -480,6 +480,8 @@ struct zone { unsigned long compact_cached_free_pfn; /* pfn where async and sync compaction migration scanner should start */ unsigned long compact_cached_migrate_pfn[2]; + unsigned long compact_init_migrate_pfn; + unsigned long compact_init_free_pfn; #endif #ifdef CONFIG_COMPACTION |