Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752632AbbH2JWZ (ORCPT ); Sat, 29 Aug 2015 05:22:25 -0400 Received: from mail-wi0-f181.google.com ([209.85.212.181]:37054 "EHLO mail-wi0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752169AbbH2JWY (ORCPT ); Sat, 29 Aug 2015 05:22:24 -0400 Date: Sat, 29 Aug 2015 11:22:19 +0200 From: Ingo Molnar To: Linus Torvalds Cc: Eric Dumazet , Al Viro , "linux-kernel@vger.kernel.org" , Oleg Nesterov , Andrew Morton , Thomas Gleixner , Maciej =?utf-8?Q?=C5=BBenczykowski?= Subject: Re: [PATCH] task_work: remove fifo ordering guarantee Message-ID: <20150829092219.GA8916@gmail.com> References: <1440816150.8932.123.camel@edumazet-glaptop2.roam.corp.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1341 Lines: 33 * Linus Torvalds wrote: > On Fri, Aug 28, 2015 at 7:42 PM, Eric Dumazet wrote: > > > > We could add yet another cond_resched() in the reverse loop, or we can simply > > remove the reversal, as I do not think anything would depend on order of > > task_work_add() submitted works. > > So I think this should be ok, with things like file closing not really caring > about ordering as far as I can tell. > > However, has anybody gone through all the task-work users? I looked quickly at > the task_work_add() cases, and didn't see anything that looked like it would > care, but others should look too. In the vfs, theres' the delayed fput and mnt > freeing, and there's a keyring installation one. > > The threaded irq handlers use it as that exit-time hack, which certainly > shouldn't care, and there's some uprobe thing. > > Can anybody see anything fishy? So I'm wondering, is there any strong reason why we couldn't use a double linked list and still do FIFO and remove that silly linear list walking hack? Thanks, Ingo -- 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/