From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qc0-f181.google.com (mail-qc0-f181.google.com [209.85.216.181]) by kanga.kvack.org (Postfix) with ESMTP id 4A75E6B0069 for ; Mon, 27 Oct 2014 11:18:13 -0400 (EDT) Received: by mail-qc0-f181.google.com with SMTP id w7so1382058qcr.40 for ; Mon, 27 Oct 2014 08:18:13 -0700 (PDT) Received: from mail-qa0-x231.google.com (mail-qa0-x231.google.com. [2607:f8b0:400d:c00::231]) by mx.google.com with ESMTPS id c3si21158525qan.79.2014.10.27.08.18.12 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 27 Oct 2014 08:18:12 -0700 (PDT) Received: by mail-qa0-f49.google.com with SMTP id i13so2003586qae.8 for ; Mon, 27 Oct 2014 08:18:09 -0700 (PDT) Date: Mon, 27 Oct 2014 11:18:06 -0400 From: Tejun Heo Subject: Re: [PATCH RESEND 2/4] cpuset: simplify cpuset_node_allowed API Message-ID: <20141027151806.GR4436@htj.dyndns.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Vladimir Davydov Cc: Andrew Morton , David Rientjes , Christoph Lameter , Zefan Li , Pekka Enberg , Joonsoo Kim , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Mon, Oct 20, 2014 at 03:50:30PM +0400, Vladimir Davydov wrote: > Current cpuset API for checking if a zone/node is allowed to allocate > from looks rather awkward. We have hardwall and softwall versions of > cpuset_node_allowed with the softwall version doing literally the same > as the hardwall version if __GFP_HARDWALL is passed to it in gfp flags. > If it isn't, the softwall version may check the given node against the > enclosing hardwall cpuset, which it needs to take the callback lock to > do. > > Such a distinction was introduced by commit 02a0e53d8227 ("cpuset: > rework cpuset_zone_allowed api"). Before, we had the only version with > the __GFP_HARDWALL flag determining its behavior. The purpose of the > commit was to avoid sleep-in-atomic bugs when someone would mistakenly > call the function without the __GFP_HARDWALL flag for an atomic > allocation. The suffixes introduced were intended to make the callers > think before using the function. > > However, since the callback lock was converted from mutex to spinlock by > the previous patch, the softwall check function cannot sleep, and these > precautions are no longer necessary. > > So let's simplify the API back to the single check. > > Suggested-by: David Rientjes > Signed-off-by: Vladimir Davydov > Acked-by: Christoph Lameter > Acked-by: Zefan Li Applied 1-2 to cgroup/for-3.19-cpuset-api-simplification which contains only these two patches on top of v3.18-rc2 and will stay stable. sl[au]b trees can pull it in or I can take the other two patches too. Please let me know how the other two should be routed. Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org