From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f174.google.com (mail-io0-f174.google.com [209.85.223.174]) by kanga.kvack.org (Postfix) with ESMTP id 4EAF96B0255 for ; Wed, 14 Oct 2015 14:58:32 -0400 (EDT) Received: by iodv82 with SMTP id v82so65820405iod.0 for ; Wed, 14 Oct 2015 11:58:32 -0700 (PDT) Received: from resqmta-ch2-09v.sys.comcast.net (resqmta-ch2-09v.sys.comcast.net. [2001:558:fe21:29:69:252:207:41]) by mx.google.com with ESMTPS id q6si18234593igr.43.2015.10.14.11.58.31 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Wed, 14 Oct 2015 11:58:31 -0700 (PDT) Date: Wed, 14 Oct 2015 13:58:30 -0500 (CDT) From: Christoph Lameter Subject: Re: [GIT PULL] workqueue fixes for v4.3-rc5 In-Reply-To: Message-ID: References: <20151013214952.GB23106@mtj.duckdns.org> <20151014165729.GA12799@mtj.duckdns.org> Content-Type: text/plain; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Linus Torvalds Cc: Tejun Heo , Andrew Morton , Michal Hocko , Linux Kernel Mailing List , Lai Jiangshan , Shaohua Li , linux-mm On Wed, 14 Oct 2015, Linus Torvalds wrote: > On Wed, Oct 14, 2015 at 10:57 AM, Christoph Lameter wrote: > > > > Well yes the schedule_delayed_work_on() call is from another cpu and the > > schedule_delayed_work() from the same. No confusion there. > > So "schedule_delayed_work()" does *not* guarantee that the work will > run on the same CPU. That is news to me. As far as I know: The only workqueue that is not guaranteed to run on the same cpu is an unbound workqueue. > If you want the scheduled work to happen on a particular CPU, then you > should use "schedule_delayed_work_on()" It shouldn't matter which CPU > you call it from. Ok then lets audit the kernel for this if that assumption is no longer true. > At least that's how I think the rules should be. Very simple, very > clear: if you require a specific CPU, say so. Don't silently depend on > "in practice, lots of times we tend to use the local cpu". As far as I can remember this was guaranteed and not just practice. -- 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