From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH 1/5] mm: Add __GFP_NO_OOM_KILL flag Date: Thu, 7 May 2009 22:18:49 +0200 Message-ID: <200905072218.50782.rjw__15195.7290982411$1241727750$gmane$org@sisk.pl> References: <200905072133.48917.rjw@sisk.pl> <20090507130202.34cbe37a.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090507130202.34cbe37a.akpm@linux-foundation.org> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: Andrew Morton Cc: kernel-testers@vger.kernel.org, rientjes@google.com, linux-kernel@vger.kernel.org, alan-jenkins@tuffmail.co.uk, jens.axboe@oracle.com, linux-pm@lists.linux-foundation.org, fengguang.wu@intel.com, torvalds@linux-foundation.org List-Id: linux-pm@vger.kernel.org On Thursday 07 May 2009, Andrew Morton wrote: > 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. OK, let's try with __GFP_NO_OOM_KILL first. If there's too much disagreement, I'll use the freezer-based approach instead.