From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B75BCC4707E for ; Thu, 10 Mar 2022 14:41:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245260AbiCJOjV (ORCPT ); Thu, 10 Mar 2022 09:39:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51990 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343855AbiCJObZ (ORCPT ); Thu, 10 Mar 2022 09:31:25 -0500 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C3FAC6261 for ; Thu, 10 Mar 2022 06:27:40 -0800 (PST) Received: by verein.lst.de (Postfix, from userid 2407) id B305468B05; Thu, 10 Mar 2022 15:27:36 +0100 (CET) Date: Thu, 10 Mar 2022 15:27:36 +0100 From: Christoph Hellwig To: Jens Axboe Cc: Christoph Hellwig , linux-kernel@vger.kernel.org Subject: Re: [PATCH] task_work: simplify the task_work_add() interface Message-ID: <20220310142736.GA1103@lst.de> References: <20220223072754.616027-1-hch@lst.de> <58c5f828-df7d-6698-e2d6-2a869e134dd4@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <58c5f828-df7d-6698-e2d6-2a869e134dd4@kernel.dk> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 10, 2022 at 05:43:25AM -0700, Jens Axboe wrote: > On 2/23/22 12:27 AM, Christoph Hellwig wrote: > > Provide a low-level task_work_add_nonotify interface that just adds > > the work to the list and open code the TWA_SIGNAL and TWA_NONE callers > > using it. task_work_add() itself now only handles the common TWA_RESUME > > case and can drop the notify argument. > > Not sure this is much of a cleanup, and a potential fast case of > TWA_NONE will now still still set TIF_NOTIFY_RESUME. Also: No, the old TWA_NONE case is switched to task_work_add_nonotify and does not set TIF_NOTIFY_RESUME. > > > diff --git a/fs/io_uring.c b/fs/io_uring.c > > index 77b9c7e4793bf..94116a102dc61 100644 > > --- a/fs/io_uring.c > > +++ b/fs/io_uring.c > > @@ -9606,7 +9606,7 @@ static __cold void io_ring_exit_work(struct work_struct *work) > > ctx_node); > > /* don't spin on a single task if cancellation failed */ > > list_rotate_left(&ctx->tctx_list); > > - ret = task_work_add(node->task, &exit.task_work, TWA_SIGNAL); > > + ret = task_work_add_nonotify(node->task, &exit.task_work); > > if (WARN_ON_ONCE(ret)) > > continue; > > This one is now no longer setting TIF_NOTIFY_SIGNAL. Yes, this was a rebase bug. > If you want to get rid of the argument, why not just have separate > helpers? task_work_add_signal(), task_work_add_resume(), > task_work_add(). Setting TWA_RESUME unconditionally because it's the > common use case doesn't seem ideal. In this series, task_work_add_nonotify is what you seems to call task_work_add, task_work_add is this series is what you call task_work_add_resume and task_work_add_signal is open coded because there aren't a whole lot of users. But if you want I can add task_work_add_signal and rename task_work_add to task_work_add_resume, but I think keeping the task_work_add_nonotify name for the low-level helper is a lot more descriptive.