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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 658CBC433DF for ; Tue, 18 Aug 2020 16:26:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4B52D2067C for ; Tue, 18 Aug 2020 16:26:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728211AbgHRQ0J (ORCPT ); Tue, 18 Aug 2020 12:26:09 -0400 Received: from verein.lst.de ([213.95.11.211]:34191 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728134AbgHRQZp (ORCPT ); Tue, 18 Aug 2020 12:25:45 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 7089568B02; Tue, 18 Aug 2020 18:25:42 +0200 (CEST) Date: Tue, 18 Aug 2020 18:25:42 +0200 From: Christoph Hellwig To: Peter Zijlstra Cc: mingo@kernel.org, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, will@kernel.org, paulmck@kernel.org, hch@lst.de, axboe@kernel.dk, chris@chris-wilson.co.uk, davem@davemloft.net, kuba@kernel.org, fweisbec@gmail.com, oleg@redhat.com, vincent.guittot@linaro.org Subject: Re: [RFC][PATCH v2 08/10] smp,irq_work: Use the new irq_work API Message-ID: <20200818162542.GB27196@lst.de> References: <20200818105102.926463950@infradead.org> <20200818112418.460474861@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200818112418.460474861@infradead.org> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 18, 2020 at 12:51:10PM +0200, Peter Zijlstra wrote: > Convert the performance sensitive users of > smp_call_single_function_async() over to the new > irq_work_queue_remote_static(). > > The new API is marginally less crap but taking these users away allows > fixing up smp_call_single_function_async() without risk of performance > regressions. You probably want a conversion patch per subsystem so that it sticks out. What is so crap about this API? How could we as subsystem maintainers help to make it less crappy?