From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Rientjes Subject: Re: [PATCH 1/5] mm: Add __GFP_NO_OOM_KILL flag Date: Thu, 7 May 2009 13:42:39 -0700 (PDT) Message-ID: References: <200905072218.50782.rjw@sisk.pl> <200905072238.14558.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200905072238.14558.rjw@sisk.pl> 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: "Rafael J. Wysocki" Cc: kernel-testers@vger.kernel.org, linux-kernel@vger.kernel.org, alan-jenkins@tuffmail.co.uk, jens.axboe@oracle.com, Andrew Morton , fengguang.wu@intel.com, torvalds@linux-foundation.org, linux-pm@lists.linux-foundation.org List-Id: linux-pm@vger.kernel.org On Thu, 7 May 2009, Rafael J. Wysocki wrote: > > 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? > Because I agree with Christoph's concerns about needlessly adding additional gfp flags; he was responding to the proposed addition of __GFP_PANIC which could be handled in other much simpler ways just like this flag can as I've shown.