[patch 5/4 v2] oom: rename serialization helper functions

[David Rientjes <rientjes@google.com>]

On Tue, 18 Sep 2007, Christoph Lameter wrote:

> On Tue, 18 Sep 2007, David Rientjes wrote:
> 
> > -		if (oom_killer_trylock(zonelist)) {
> > +		if (zone_in_oom(zonelist)) {
> 
> The name is confusing. Looks like we are just checking a bit whereas we 
> attempt to set the zone to oom. try_set_zone_oom with the correct trylock 
> semantics?
> 

oom: rename serialization helper functions

Rename oom_killer_trylock() and oom_killer_unlock() to try_set_zone_oom()
and clear_zonelist_oom(), respectively.  Reverses the logic of
try_set_zone_oom() so that it returns zero if the zone is already found
in the OOM killer, similar to trylock semantics.

Cc: Andrea Arcangeli <andrea@suse.de>
Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: David Rientjes <rientjes@google.com>
---
 Replaces original oom-rename-serialization-helper-functions.patch.

 include/linux/oom.h |    4 ++--
 mm/oom_kill.c       |   14 +++++++-------
 mm/page_alloc.c     |    8 ++++----
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/include/linux/oom.h b/include/linux/oom.h
--- a/include/linux/oom.h
+++ b/include/linux/oom.h
@@ -20,8 +20,8 @@ enum oom_constraint {
 	CONSTRAINT_MEMORY_POLICY,
 };
 
-extern int oom_killer_trylock(struct zonelist *zonelist);
-extern void oom_killer_unlock(const struct zonelist *zonelist);
+extern int try_set_zone_oom(struct zonelist *zonelist);
+extern void clear_zonelist_oom(const struct zonelist *zonelist);
 
 extern void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order);
 extern int register_oom_notifier(struct notifier_block *nb);
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -404,20 +404,20 @@ static int is_zone_locked(const struct zone *zone)
 }
 
 /*
- * Try to acquire the OOM killer lock for the zones in zonelist.  Returns
- * non-zero if a parallel OOM killing is already taking place that includes a
- * zone in the zonelist.
+ * Try to acquire the OOM killer lock for the zones in zonelist.  Returns zero
+ * if a parallel OOM killing is already taking place that includes a zone in
+ * the zonelist.
  */
-int oom_killer_trylock(struct zonelist *zonelist)
+int try_set_zone_oom(struct zonelist *zonelist)
 {
 	struct oom_zonelist *oom_zl;
-	int ret = 0;
+	int ret = 1;
 	int i;
 
 	mutex_lock(&oom_zonelist_mutex);
 	for (i = 0; zonelist->zones[i]; i++)
 		if (is_zone_locked(zonelist->zones[i])) {
-			ret = 1;
+			ret = 0;
 			goto out;
 		}
 
@@ -436,7 +436,7 @@ out:
  * Removes the zonelist from the list so that future allocations that include
  * its zones can successfully call the OOM killer.
  */
-void oom_killer_unlock(const struct zonelist *zonelist)
+void clear_zonelist_oom(const struct zonelist *zonelist)
 {
 	struct oom_zonelist *oom_zl;
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1353,7 +1353,7 @@ nofail_alloc:
 		if (page)
 			goto got_pg;
 	} else if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
-		if (oom_killer_trylock(zonelist)) {
+		if (!try_set_zone_oom(zonelist)) {
 			schedule_timeout_uninterruptible(1);
 			goto restart;
 		}
@@ -1367,18 +1367,18 @@ nofail_alloc:
 		page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
 				zonelist, ALLOC_WMARK_HIGH|ALLOC_CPUSET);
 		if (page) {
-			oom_killer_unlock(zonelist);
+			clear_zonelist_oom(zonelist);
 			goto got_pg;
 		}
 
 		/* The OOM killer will not help higher order allocs so fail */
 		if (order > PAGE_ALLOC_COSTLY_ORDER) {
-			oom_killer_unlock(zonelist);
+			clear_zonelist_oom(zonelist);
 			goto nopage;
 		}
 
 		out_of_memory(zonelist, gfp_mask, order);
-		oom_killer_unlock(zonelist);
+		clear_zonelist_oom(zonelist);
 		goto restart;
 	}
 

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