From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751405AbZLHIxz (ORCPT ); Tue, 8 Dec 2009 03:53:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751317AbZLHIxy (ORCPT ); Tue, 8 Dec 2009 03:53:54 -0500 Received: from bombadil.infradead.org ([18.85.46.34]:51025 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751041AbZLHIxw (ORCPT ); Tue, 8 Dec 2009 03:53:52 -0500 Subject: Re: [PATCH 7/7] sched: implement try_to_wake_up_local() From: Peter Zijlstra To: Tejun Heo Cc: tglx@linutronix.de, mingo@elte.hu, avi@redhat.com, efault@gmx.de, rusty@rustcorp.com.au, linux-kernel@vger.kernel.org In-Reply-To: <4B1CD89F.9000802@kernel.org> References: <1259726212-30259-1-git-send-email-tj@kernel.org> <1259726212-30259-8-git-send-email-tj@kernel.org> <1259923487.3977.1940.camel@laptop> <4B1C75F3.9080808@kernel.org> <1260175804.8223.1217.camel@laptop> <1260176199.8223.1237.camel@laptop> <4B1CD89F.9000802@kernel.org> Content-Type: text/plain; charset="UTF-8" Date: Tue, 08 Dec 2009 09:53:14 +0100 Message-ID: <1260262394.3935.981.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2009-12-07 at 19:27 +0900, Tejun Heo wrote: > > > What happens when you run out of memory and the workqueue progress is > > needed to get free memory? > > That's when the "rescuer" workers kick in. All workqueues which might > be used during allocation paths are required to have one. When > manager fails to fork a new worker, it summons the rescuers. They > migrate to the distressed cpu and processes only the works from their > specific workqueues thus guaranteeing forward progress. What happens if the rescue worker is tied up on another cpu in a deadlock avoidance game, which requires progress on this cpu in order to resolve it?