Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1032403AbWLGQuq (ORCPT ); Thu, 7 Dec 2006 11:50:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1032406AbWLGQup (ORCPT ); Thu, 7 Dec 2006 11:50:45 -0500 Received: from smtp.osdl.org ([65.172.181.25]:43103 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1032403AbWLGQuR (ORCPT ); Thu, 7 Dec 2006 11:50:17 -0500 Date: Thu, 7 Dec 2006 08:49:02 -0800 (PST) From: Linus Torvalds To: Andrew Morton cc: David Howells , "Maciej W. Rozycki" , Roland Dreier , Andy Fleming , Ben Collins , Linux Kernel Mailing List , Jeff Garzik Subject: Re: [PATCH] Export current_is_keventd() for libphy In-Reply-To: <20061206224207.8a8335ee.akpm@osdl.org> Message-ID: References: <1165125055.5320.14.camel@gullible> <20061203011625.60268114.akpm@osdl.org> <20061205123958.497a7bd6.akpm@osdl.org> <6FD5FD7A-4CC2-481A-BC87-B869F045B347@freescale.com> <20061205132643.d16db23b.akpm@osdl.org> <20061205135753.9c3844f8.akpm@osdl.org> <20061206075729.b2b6aa52.akpm@osdl.org> <20061206224207.8a8335ee.akpm@osdl.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1079 Lines: 32 On Wed, 6 Dec 2006, Andrew Morton wrote: > > But this will return to the caller if the callback is presently running on > a different CPU. The whole point here is to be able to reliably kill off > the pending work so that the caller can free resources. I mentioned that in one of the emails. We do not _have_ the information to not do that. It simply doesn't exist. We can either wait for _all_ pending entries on the to complete (by waiting for the workqueue counters for added/removed to be the same), or we can have the race. > Also, I worry that this code can run the callback on the caller's CPU. Right. > Users of per-cpu workqueues can legitimately assume that each callback runs > on the right CPU. Not if they use this interface, they can't. They asked for it, they get it. That's the unix philosophy. Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/