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authorMinchan Kim <minchan.kim@gmail.com>2011-10-31 17:06:51 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-08-01 12:27:16 -0700
commit19faec0520b3b16dfd58cde30938a3c4d3dcdd5b (patch)
tree1a32165e3bd19c2b167e23c92f8dede9fe883ed2
parenta15a3971cc49eefbde40b397a446c0fa9c5fed9c (diff)
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mm: compaction: make isolate_lru_page() filter-aware
commit 39deaf8585152f1a35c1676d3d7dc6ae0fb65967 upstream. Stable note: Not tracked in Bugzilla. THP and compaction disrupt the LRU list leading to poor reclaim decisions which has a variable performance impact. In async mode, compaction doesn't migrate dirty or writeback pages. So, it's meaningless to pick the page and re-add it to lru list. Of course, when we isolate the page in compaction, the page might be dirty or writeback but when we try to migrate the page, the page would be not dirty, writeback. So it could be migrated. But it's very unlikely as isolate and migration cycle is much faster than writeout. So, this patch helps cpu overhead and prevent unnecessary LRU churning. Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--include/linux/mmzone.h2
-rw-r--r--mm/compaction.c7
-rw-r--r--mm/vmscan.c3
3 files changed, 10 insertions, 2 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 047ea65..0ed9149 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -162,6 +162,8 @@ static inline int is_unevictable_lru(enum lru_list l)
#define ISOLATE_INACTIVE ((__force isolate_mode_t)0x1)
/* Isolate active pages */
#define ISOLATE_ACTIVE ((__force isolate_mode_t)0x2)
+/* Isolate clean file */
+#define ISOLATE_CLEAN ((__force isolate_mode_t)0x4)
/* LRU Isolation modes. */
typedef unsigned __bitwise__ isolate_mode_t;
diff --git a/mm/compaction.c b/mm/compaction.c
index 26521a1..b30c40f 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -261,6 +261,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
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 = ISOLATE_ACTIVE|ISOLATE_INACTIVE;
/* Do not scan outside zone boundaries */
low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn);
@@ -370,9 +371,11 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
continue;
}
+ if (!cc->sync)
+ mode |= ISOLATE_CLEAN;
+
/* Try isolate the page */
- if (__isolate_lru_page(page,
- ISOLATE_ACTIVE|ISOLATE_INACTIVE, 0) != 0)
+ if (__isolate_lru_page(page, mode, 0) != 0)
continue;
VM_BUG_ON(PageTransCompound(page));
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 9267ba1..6835735 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1045,6 +1045,9 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode, int file)
ret = -EBUSY;
+ if ((mode & ISOLATE_CLEAN) && (PageDirty(page) || PageWriteback(page)))
+ return ret;
+
if (likely(get_page_unless_zero(page))) {
/*
* Be careful not to clear PageLRU until after we're