diff options
Diffstat (limited to 'mm/oom_kill.c')
| -rw-r--r-- | mm/oom_kill.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 1a7a4ef04e27..6e999c88c503 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -27,6 +27,7 @@ #include <linux/notifier.h> int sysctl_panic_on_oom; +static DEFINE_MUTEX(zone_scan_mutex); /* #define DEBUG */ /** @@ -374,6 +375,57 @@ int unregister_oom_notifier(struct notifier_block *nb) } EXPORT_SYMBOL_GPL(unregister_oom_notifier); +/* + * 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. Otherwise, locks all zones in the zonelist and returns 1. + */ +int try_set_zone_oom(struct zonelist *zonelist) +{ + struct zone **z; + int ret = 1; + + z = zonelist->zones; + + mutex_lock(&zone_scan_mutex); + do { + if (zone_is_oom_locked(*z)) { + ret = 0; + goto out; + } + } while (*(++z) != NULL); + + /* + * Lock each zone in the zonelist under zone_scan_mutex so a parallel + * invocation of try_set_zone_oom() doesn't succeed when it shouldn't. + */ + z = zonelist->zones; + do { + zone_set_flag(*z, ZONE_OOM_LOCKED); + } while (*(++z) != NULL); +out: + mutex_unlock(&zone_scan_mutex); + return ret; +} + +/* + * Clears the ZONE_OOM_LOCKED flag for all zones in the zonelist so that failed + * allocation attempts with zonelists containing them may now recall the OOM + * killer, if necessary. + */ +void clear_zonelist_oom(struct zonelist *zonelist) +{ + struct zone **z; + + z = zonelist->zones; + + mutex_lock(&zone_scan_mutex); + do { + zone_clear_flag(*z, ZONE_OOM_LOCKED); + } while (*(++z) != NULL); + mutex_unlock(&zone_scan_mutex); +} + /** * out_of_memory - kill the "best" process when we run out of memory * |