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 22:38:13 +0200 Message-ID: <200905072238.14558.rjw__19902.5202928626$1241728955$gmane$org@sisk.pl> References: <200905072218.50782.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: 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: David Rientjes , Andrew Morton Cc: kernel-testers@vger.kernel.org, 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, David Rientjes wrote: > On Thu, 7 May 2009, Rafael J. Wysocki wrote: > > > OK, let's try with __GFP_NO_OOM_KILL first. If there's too much disagreement, > > I'll use the freezer-based approach instead. > > > > Third time I'm going to suggest this, and I'd like a response on why it's > not possible instead of being ignored. > > All of your tasks are in D state other than kthreads, right? That means > they won't be in the oom killer (thus no zones are oom locked), so you can > easily do this > > struct zone *z; > for_each_populated_zone(z) > zone_set_flag(z, ZONE_OOM_LOCKED); > > and then > > for_each_populated_zone(z) > zone_clear_flag(z, ZONE_OOM_LOCKED); > > The serialization is done with trylocks so this will never invoke the oom > killer because all zones in the allocator's zonelist will be oom locked. > > Why does this not work for you? Well, it might work too, but why are you insisting? How's it better than __GFP_NO_OOM_KILL, actually? Andrew, what do you think about this?