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authorVlastimil Babka <vbabka@suse.cz>2014-10-09 15:27:09 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-10-09 22:25:54 -0400
commitedc2ca61249679298c1f343cd9c549964b8df4b4 (patch)
tree4422c9e43dc5929c28c7b72c36247966a169b0d2 /mm/internal.h
parentf8224aa5a0a4627926019bba7511926393fbee3b (diff)
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mm, compaction: move pageblock checks up from isolate_migratepages_range()
isolate_migratepages_range() is the main function of the compaction scanner, called either on a single pageblock by isolate_migratepages() during regular compaction, or on an arbitrary range by CMA's __alloc_contig_migrate_range(). It currently perfoms two pageblock-wide compaction suitability checks, and because of the CMA callpath, it tracks if it crossed a pageblock boundary in order to repeat those checks. However, closer inspection shows that those checks are always true for CMA: - isolation_suitable() is true because CMA sets cc->ignore_skip_hint to true - migrate_async_suitable() check is skipped because CMA uses sync compaction We can therefore move the compaction-specific checks to isolate_migratepages() and simplify isolate_migratepages_range(). Furthermore, we can mimic the freepage scanner family of functions, which has isolate_freepages_block() function called both by compaction from isolate_freepages() and by CMA from isolate_freepages_range(), where each use-case adds own specific glue code. This allows further code simplification. Thus, we rename isolate_migratepages_range() to isolate_migratepages_block() and limit its functionality to a single pageblock (or its subset). For CMA, a new different isolate_migratepages_range() is created as a CMA-specific wrapper for the _block() function. The checks specific to compaction are moved to isolate_migratepages(). As part of the unification of these two families of functions, we remove the redundant zone parameter where applicable, since zone pointer is already passed in cc->zone. Furthermore, going back to compact_zone() and compact_finished() when pageblock is found unsuitable (now by isolate_migratepages()) is wasteful - the checks are meant to skip pageblocks quickly. The patch therefore also introduces a simple loop into isolate_migratepages() so that it does not return immediately on failed pageblock checks, but keeps going until isolate_migratepages_range() gets called once. Similarily to isolate_freepages(), the function periodically checks if it needs to reschedule or abort async compaction. [iamjoonsoo.kim@lge.com: fix isolated page counting bug in compaction] Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Minchan Kim <minchan@kernel.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Christoph Lameter <cl@linux.com> Cc: Rik van Riel <riel@redhat.com> Cc: David Rientjes <rientjes@google.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.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/internal.h b/mm/internal.h
index a1b651b..5a0738f 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -154,8 +154,8 @@ unsigned long
isolate_freepages_range(struct compact_control *cc,
unsigned long start_pfn, unsigned long end_pfn);
unsigned long
-isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
- unsigned long low_pfn, unsigned long end_pfn, bool unevictable);
+isolate_migratepages_range(struct compact_control *cc,
+ unsigned long low_pfn, unsigned long end_pfn);
#endif
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