Re: [PATCH] mm: avoid livelock on !__GFP_FS allocations

From: Pekka Enberg
Date: Wed Nov 16 2011 - 02:10:45 EST


On Wed, 16 Nov 2011, Minchan Kim wrote:
Then, How about this?

[barrios@barrios-laptop linux-2.6]$ git diff
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index fdd4263..01aa9b5 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -297,9 +297,11 @@ int enter_state(suspend_state_t state)
goto Finish;

pr_debug("PM: Entering %s sleep\n", pm_states[state]);
+ oom_killer_disable();
pm_restrict_gfp_mask();
error = suspend_devices_and_enter(state);
pm_restore_gfp_mask();
+ oom_killer_enable();

Finish:
pr_debug("PM: Finishing wakeup.\n");
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6e8ecb6..d8c31b7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2177,9 +2177,9 @@ rebalance:
* running out of options and have to consider going OOM
*/
if (!did_some_progress) {
- if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
- if (oom_killer_disabled)
+ if (oom_killer_disabled)
goto nopage;
+ if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
page = __alloc_pages_may_oom(gfp_mask, order,
zonelist, high_zoneidx,
nodemask, preferred_zone,


I'd prefer something like this. The whole 'gfp_allowed_flags' thing was designed to make GFP_KERNEL work during boot time where it's obviously safe to do that. I really don't think that's going to work suspend cleanly.

Pekka
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