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authorDavid Rientjes <rientjes@google.com>2007-10-16 23:26:01 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-17 08:42:46 -0700
commitd773ed6b856a96bd6d18b6e04455e3ced0876da4 (patch)
treef0235be6843ec323aeedcdadbee34a777b6c2690 /include
parentae74138da609c576b221c765efa8b81b2365f465 (diff)
mm: test and set zone reclaim lock before starting reclaim
Introduces new zone flag interface for testing and setting flags: int zone_test_and_set_flag(struct zone *zone, zone_flags_t flag) Instead of setting and clearing ZONE_RECLAIM_LOCKED each time shrink_zone() is called, this flag is test and set before starting zone reclaim. Zone reclaim starts in __alloc_pages() when a zone's watermark fails and the system is in zone_reclaim_mode. If it's already in reclaim, there's no need to start again so it is simply considered full for that allocation attempt. There is a change of behavior with regard to concurrent zone shrinking. It is now possible for try_to_free_pages() or kswapd to already be shrinking a particular zone when __alloc_pages() starts zone reclaim. In this case, it is possible for two concurrent threads to invoke shrink_zone() for a single zone. This change forbids a zone to be in zone reclaim twice, which was always the behavior, but allows for concurrent try_to_free_pages() or kswapd shrinking when starting zone reclaim. Cc: Andrea Arcangeli <andrea@suse.de> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: 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 'include')
-rw-r--r--include/linux/mmzone.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 9011505e740..4c4522a51a3 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -351,6 +351,12 @@ static inline void zone_set_flag(struct zone *zone, zone_flags_t flag)
{
set_bit(flag, &zone->flags);
}
+
+static inline int zone_test_and_set_flag(struct zone *zone, zone_flags_t flag)
+{
+ return test_and_set_bit(flag, &zone->flags);
+}
+
static inline void zone_clear_flag(struct zone *zone, zone_flags_t flag)
{
clear_bit(flag, &zone->flags);
@@ -360,10 +366,12 @@ static inline int zone_is_all_unreclaimable(const struct zone *zone)
{
return test_bit(ZONE_ALL_UNRECLAIMABLE, &zone->flags);
}
+
static inline int zone_is_reclaim_locked(const struct zone *zone)
{
return test_bit(ZONE_RECLAIM_LOCKED, &zone->flags);
}
+
static inline int zone_is_oom_locked(const struct zone *zone)
{
return test_bit(ZONE_OOM_LOCKED, &zone->flags);