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>
diff --git a/mm/compaction.c b/mm/compaction.c
index 054c28b..37f9762 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -460,12 +460,13 @@
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 @@
continue;
}
- if (!cc->sync)
- mode |= ISOLATE_ASYNC_MIGRATE;
-
- if (unevictable)
- mode |= ISOLATE_UNEVICTABLE;
-
lruvec = mem_cgroup_page_lruvec(page, zone);
/* Try isolate the page */