From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752808AbbFIDBK (ORCPT ); Mon, 8 Jun 2015 23:01:10 -0400 Received: from mail-pa0-f51.google.com ([209.85.220.51]:35297 "EHLO mail-pa0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751511AbbFIDBC (ORCPT ); Mon, 8 Jun 2015 23:01:02 -0400 Date: Tue, 9 Jun 2015 12:00:54 +0900 From: Tejun Heo To: Jeff Moyer Cc: axboe@kernel.dk, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, vgoyal@redhat.com, avanzini.arianna@gmail.com Subject: Re: [PATCH 5/8] cfq-iosched: remove @gfp_mask from cfq_find_alloc_queue() Message-ID: <20150609030054.GJ21465@mtj.duckdns.org> References: <1433753973-23684-1-git-send-email-tj@kernel.org> <1433753973-23684-6-git-send-email-tj@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hey, Jeff. On Mon, Jun 08, 2015 at 04:27:10PM -0400, Jeff Moyer wrote: > >> Remove @gfp_mask from cfq_find_alloc_queue() and propagate the changes > >> to its callers. This simplifies the function quite a bit and will > >> help making async queues per-cfq_group. > > > > Sorry, I disagree with this patch. You've changed it so that all cfqq > > allocations are GFP_ATOMIC, and most, if not all of them simply don't > > need to be. > > It occurs to me that replacing GFP_ATOMIC with GFP_NOWAIT in your patch > would address my concerns, and patches 6-8 would apply almost as-is. > What do you think about that? Oh yeah, it's okay to fail these allocations under memory pressure. GFP_NOWAIT is the better pick here. It's GFP_ATOMIC mostly due to historic copy&paste anyway. I'll change them to GFP_NOWAIT. Thanks. -- tejun