From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH 1/5] mm: Add __GFP_NO_OOM_KILL flag Date: Thu, 7 May 2009 13:02:02 -0700 Message-ID: <20090507130202.34cbe37a.akpm@linux-foundation.org> References: <200905072009.53406.rjw@sisk.pl> <20090507114807.d7c6d26a.akpm@linux-foundation.org> <200905072133.48917.rjw@sisk.pl> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200905072133.48917.rjw-KKrjLPT3xs0@public.gmane.org> Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: "Rafael J. Wysocki" Cc: rientjes-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, fengguang.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, linux-pm-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, pavel-+ZI9xUNit7I@public.gmane.org, torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, alan-jenkins-cCz0Lq7MMjm9FHfhHBbuYA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-testers-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On Thu, 7 May 2009 21:33:47 +0200 "Rafael J. Wysocki" wrote: > On Thursday 07 May 2009, Andrew Morton wrote: > > On Thu, 7 May 2009 20:09:52 +0200 > > "Rafael J. Wysocki" wrote: > > > > > > > > I'm suspecting that hibernation can allocate its pages with > > > > > > __GFP_FS|__GFP_WAIT|__GFP_NORETRY|__GFP_NOWARN, and the page allocator > > > > > > will dtrt: no oom-killings. > > > > > > > > > > > > In which case, processes_are_frozen() is not needed at all? > > > > > > > > > > __GFP_NORETRY alone causes it to fail relatively quickly, but I'll try with > > > > > the combination. > > > > > > > > OK. __GFP_WAIT is the big hammer. > > > > > > Unfortunately it fails too quickly with the combination as well, so it looks > > > like we can't use __GFP_NORETRY during hibernation. > > > > hm. > > > > So where do we stand now? > > > > I'm not a big fan of the global application-specific state change > > thing. Something like __GFP_NO_OOM_KILL has a better chance of being > > reused by other subsystems in the future, which is a good indicator. > > I'm not against __GFP_NO_OOM_KILL, but there's been some strong resistance to > adding new _GPF _FOO flags recently. We have six or seven left - hardly a crisis. > Is there any likelihood anyone else we'll > really need it any time soon? Dunno - people do all sorts of crazy things. But it's more likely to be reused than a PM-specific global! I have no strong feelings really, but slotting into the existing technique with something which might be reusable is quite a bit tidier.