From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757432Ab2BWXZG (ORCPT ); Thu, 23 Feb 2012 18:25:06 -0500 Received: from mail-pz0-f46.google.com ([209.85.210.46]:64074 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756566Ab2BWXZD (ORCPT ); Thu, 23 Feb 2012 18:25:03 -0500 Authentication-Results: mr.google.com; spf=pass (google.com: domain of htejun@gmail.com designates 10.68.225.73 as permitted sender) smtp.mail=htejun@gmail.com; dkim=pass header.i=htejun@gmail.com Date: Thu, 23 Feb 2012 15:24:58 -0800 From: Tejun Heo To: Andrew Morton Cc: vgoyal@redhat.com, axboe@kernel.dk, hughd@google.com, avi@redhat.com, nate@cpanel.net, cl@linux-foundation.org, linux-kernel@vger.kernel.org, dpshah@google.com, ctalbott@google.com, rni@google.com Subject: Re: [PATCHSET] mempool, percpu, blkcg: fix percpu stat allocation and remove stats_lock Message-ID: <20120223232458.GN22536@google.com> References: <1330036246-21633-1-git-send-email-tj@kernel.org> <20120223144336.58742e1b.akpm@linux-foundation.org> <20120223230123.GL22536@google.com> <20120223231204.GM22536@google.com> <20120223152223.43c72ccb.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120223152223.43c72ccb.akpm@linux-foundation.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Andrew. On Thu, Feb 23, 2012 at 03:22:23PM -0800, Andrew Morton wrote: > I forget how those patches work, but they might be vulnerable to the > same issue. If the block layer can handle the failed allocation > attempt and retry at the next I/O event then I guess that would be > acceptable; we'd lose a bit of statistical info occasionally, but who > cares. > > But ISTR that we can't handle allocation failures here? It's just gonna skip percpu stats. The problem with percpu mempool is more about what __GFP_WAIT means in the interface. Handling alloc failure isn't difficult at all. Thanks. -- tejun