From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta8.messagelabs.com (mail6.bemta8.messagelabs.com [216.82.243.55]) by kanga.kvack.org (Postfix) with ESMTP id 49D346B0074 for ; Wed, 16 Nov 2011 16:55:56 -0500 (EST) From: "Rafael J. Wysocki" Subject: Re: [PATCH] mm: avoid livelock on !__GFP_FS allocations Date: Wed, 16 Nov 2011 22:58:39 +0100 References: <20111114140421.GA27150@suse.de> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201111162258.39346.rjw@sisk.pl> Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: Pekka Enberg , Minchan Kim , Colin Cross , Mel Gorman , Andrew Morton , Pekka Enberg , KAMEZAWA Hiroyuki , Andrea Arcangeli , LKML , Linux-MM On Wednesday, November 16, 2011, David Rientjes wrote: > 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. Yes, it has. > 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. Good. :-) Thanks, Rafael -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org