mm, compaction: determine isolation mode only once

The conditions that control the isolation mode in
isolate_migratepages_range() do not change during the iteration, so
extract them out and only define the value once.

This actually does have an effect, gcc doesn't optimize it itself because
of cc->sync.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Rientjes 2014-04-07 15:37:34 -07:00 коммит произвёл Linus Torvalds
Родитель 539a13b47e
Коммит da1c67a76f
1 изменённых файлов: 2 добавлений и 7 удалений

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@ -460,12 +460,13 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
unsigned long last_pageblock_nr = 0, pageblock_nr;
unsigned long nr_scanned = 0, nr_isolated = 0;
struct list_head *migratelist = &cc->migratepages;
isolate_mode_t mode = 0;
struct lruvec *lruvec;
unsigned long flags;
bool locked = false;
struct page *page = NULL, *valid_page = NULL;
bool skipped_async_unsuitable = false;
const isolate_mode_t mode = (!cc->sync ? ISOLATE_ASYNC_MIGRATE : 0) |
(unevictable ? ISOLATE_UNEVICTABLE : 0);
/*
* Ensure that there are not too many pages isolated from the LRU
@ -608,12 +609,6 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
continue;
}
if (!cc->sync)
mode |= ISOLATE_ASYNC_MIGRATE;
if (unevictable)
mode |= ISOLATE_UNEVICTABLE;
lruvec = mem_cgroup_page_lruvec(page, zone);
/* Try isolate the page */