To lock the entire system from parallel oom killing, it's possible to
pass in a zonelist with all zones rather than using
for_each_populated_zone() for the iteration. This obsoletes
try_set_system_oom() and clear_system_oom() so that they can be removed.
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
---
mm/oom_kill.c | 49 +++++++------------------------------------------
1 files changed, 7 insertions(+), 42 deletions(-)
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -591,43 +591,6 @@ void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask)
spin_unlock(&zone_scan_lock);
}
-/*
- * Try to acquire the oom killer lock for all system zones. Returns zero if a
- * parallel oom killing is taking place, otherwise locks all zones and returns
- * non-zero.
- */
-static int try_set_system_oom(void)
-{
- struct zone *zone;
- int ret = 1;
-
- spin_lock(&zone_scan_lock);
- for_each_populated_zone(zone)
- if (zone_is_oom_locked(zone)) {
- ret = 0;
- goto out;
- }
- for_each_populated_zone(zone)
- zone_set_flag(zone, ZONE_OOM_LOCKED);
-out:
- spin_unlock(&zone_scan_lock);
- return ret;
-}
-
-/*
- * Clears ZONE_OOM_LOCKED for all system zones so that failed allocation
- * attempts or page faults may now recall the oom killer, if necessary.
- */
-static void clear_system_oom(void)
-{
- struct zone *zone;
-
- spin_lock(&zone_scan_lock);
- for_each_populated_zone(zone)
- zone_clear_flag(zone, ZONE_OOM_LOCKED);
- spin_unlock(&zone_scan_lock);
-}
-
/**
* out_of_memory - kill the "best" process when we run out of memory
* @zonelist: zonelist pointer
@@ -708,15 +671,17 @@ out:
/*
* The pagefault handler calls here because it is out of memory, so kill a
- * memory-hogging task. If a populated zone has ZONE_OOM_LOCKED set, a parallel
- * oom killing is already in progress so do nothing. If a task is found with
- * TIF_MEMDIE set, it has been killed so do nothing and allow it to exit.
+ * memory-hogging task. If any populated zone has ZONE_OOM_LOCKED set, a
+ * parallel oom killing is already in progress so do nothing.
*/
void pagefault_out_of_memory(void)
{
- if (try_set_system_oom()) {
+ struct zonelist *zonelist = node_zonelist(first_online_node,
+ GFP_KERNEL);
+
+ if (try_set_zonelist_oom(zonelist, GFP_KERNEL)) {
out_of_memory(NULL, 0, 0, NULL, false);
- clear_system_oom();
+ clear_zonelist_oom(zonelist, GFP_KERNEL);
}
schedule_timeout_killable(1);
}
--
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