Messages in this thread | | | Date | Wed, 16 Nov 2011 13:44:17 -0800 (PST) | From | David Rientjes <> | Subject | Re: [PATCH] mm: avoid livelock on !__GFP_FS allocations |
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On Wed, 16 Nov 2011, Pekka Enberg wrote:
> > 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;
You're allowing __GFP_NOFAIL allocations to fail.
> > + 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. >
Adding Rafael to the cc.
This has been done since 2.6.34 and presumably has been working quite well. I don't have a specific objection to gfp_allowed_flags to be used outside of boot since it seems plausible that there are system-level contexts that would need different behavior in the page allocator and this does it effectively without major surgery or a slower fastpath. Suspend is using it just like boot does before irqs are enabled, so I don't have an objection to it.
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