diff options
| -rw-r--r-- | mm/oom_kill.c | 86 |
1 files changed, 57 insertions, 29 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index fca886d..dad13fc 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -631,6 +631,44 @@ void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask) } /* + * 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); +} + + +/* * Must be called with tasklist_lock held for read. */ static void __out_of_memory(gfp_t gfp_mask, int order, @@ -665,33 +703,6 @@ retry: goto retry; } -/* - * pagefault handler calls into here because it is out of memory but - * doesn't know exactly how or why. - */ -void pagefault_out_of_memory(void) -{ - unsigned long freed = 0; - - blocking_notifier_call_chain(&oom_notify_list, 0, &freed); - if (freed > 0) - /* Got some memory back in the last second. */ - return; - - check_panic_on_oom(CONSTRAINT_NONE, 0, 0); - read_lock(&tasklist_lock); - /* unknown gfp_mask and order */ - __out_of_memory(0, 0, CONSTRAINT_NONE, NULL); - read_unlock(&tasklist_lock); - - /* - * Give "p" a good chance of killing itself before we - * retry to allocate memory. - */ - if (!test_thread_flag(TIF_MEMDIE)) - schedule_timeout_uninterruptible(1); -} - /** * out_of_memory - kill the "best" process when we run out of memory * @zonelist: zonelist pointer @@ -708,7 +719,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order, nodemask_t *nodemask) { unsigned long freed = 0; - enum oom_constraint constraint; + enum oom_constraint constraint = CONSTRAINT_NONE; blocking_notifier_call_chain(&oom_notify_list, 0, &freed); if (freed > 0) @@ -729,7 +740,8 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, * Check if there were limitations on the allocation (only relevant for * NUMA) that may require different handling. */ - constraint = constrained_alloc(zonelist, gfp_mask, nodemask); + if (zonelist) + constraint = constrained_alloc(zonelist, gfp_mask, nodemask); check_panic_on_oom(constraint, gfp_mask, order); read_lock(&tasklist_lock); __out_of_memory(gfp_mask, order, constraint, nodemask); @@ -742,3 +754,19 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, if (!test_thread_flag(TIF_MEMDIE)) schedule_timeout_uninterruptible(1); } + +/* + * 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. + */ +void pagefault_out_of_memory(void) +{ + if (try_set_system_oom()) { + out_of_memory(NULL, 0, 0, NULL); + clear_system_oom(); + } + if (!test_thread_flag(TIF_MEMDIE)) + schedule_timeout_uninterruptible(1); +} |