diff options
| author |   Mel Gorman <mgorman@techsingularity.net> | 2019-03-05 15:45:31 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2019-03-05 21:07:17 -0800 |
| commit | dbe2d4e4f12e07c6a2215e3603a5f77056323081 (patch) | |
| tree | 03ac02c91b3900b20c999bbc48c064f5c584afd6 /mm/internal.h | |
| parent | mm, compaction: reduce premature advancement of the migration target scanner (diff) | |
| download | linux-dev-dbe2d4e4f12e07c6a2215e3603a5f77056323081.tar.xz linux-dev-dbe2d4e4f12e07c6a2215e3603a5f77056323081.zip | |
mm, compaction: round-robin the order while searching the free lists for a target
As compaction proceeds and creates high-order blocks, the free list
search gets less efficient as the larger blocks are used as compaction
targets. Eventually, the larger blocks will be behind the migration
scanner for partially migrated pageblocks and the search fails. This
patch round-robins what orders are searched so that larger blocks can be
ignored and find smaller blocks that can be used as migration targets.
The overall impact was small on 1-socket but it avoids corner cases
where the migration/free scanners meet prematurely or situations where
many of the pageblocks encountered by the free scanner are almost full
instead of being properly packed. Previous testing had indicated that
without this patch there were occasional large spikes in the free
scanner without this patch.
[dan.carpenter@oracle.com: fix static checker warning]
Link: http://lkml.kernel.org/r/20190118175136.31341-20-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/internal.h')
| -rw-r--r-- | mm/internal.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/internal.h b/mm/internal.h index d5b999e5eb5f..31bb0be6fd52 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -192,7 +192,8 @@ struct compact_control { struct zone *zone; unsigned long total_migrate_scanned; unsigned long total_free_scanned; - unsigned int fast_search_fail; /* failures to use free list searches */ + unsigned short fast_search_fail;/* failures to use free list searches */ + short search_order; /* order to start a fast search at */ const gfp_t gfp_mask; /* gfp mask of a direct compactor */ int order; /* order a direct compactor needs */ int migratetype; /* migratetype of direct compactor */ |