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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 455B1C433E0 for ; Mon, 8 Jun 2020 16:42:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 11C51206A4 for ; Mon, 8 Jun 2020 16:42:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="rWAp0eVZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730628AbgFHQm6 (ORCPT ); Mon, 8 Jun 2020 12:42:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730443AbgFHQm5 (ORCPT ); Mon, 8 Jun 2020 12:42:57 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6DA9DC08C5C2; Mon, 8 Jun 2020 09:42:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=DRRAq81V5Jd47SWIu2YH0vKG19isDDXhAsvjOLVV/U8=; b=rWAp0eVZ7yupBOLKGXGZYoxwzY KXi0EbCKQwia/vRYAgT948E/ltRfPuWkZSAy2co+VmkC/IxxaybOKN73/TY3sEBDlmSPet8o19yuP voc5jwmkPnads1yvovxRKf2aQ3sesSyLWguzlAu9J/0O+Hd+rb6KA008tgg9JvZ8LsY4NtfsHSg1+ Uv73WN3EekQqPoVw6s8nB+VtrDcTV87RpquFKSaqrH+G9KE2nj4yJzYh6NIcNgbWmYCIGiWtOnMYU AtFlxB+91pKF2glliIQa+XUahiaF5g+F1Sdx3xHtFnlk5rBGZo9s/OLef/qLgz1mM38noSEVurahF PYnPFALQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jiKrO-0003K1-5A; Mon, 08 Jun 2020 16:42:54 +0000 Date: Mon, 8 Jun 2020 09:42:54 -0700 From: Christoph Hellwig To: Peter Zijlstra Cc: Christoph Hellwig , Jens Axboe , frederic@kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org Subject: Re: blk-softirq vs smp_call_function_single_async() Message-ID: <20200608164254.GA2431@infradead.org> References: <20200608115800.GA2531@hirez.programming.kicks-ass.net> <20200608154557.GA26611@infradead.org> <20200608155833.GC2531@hirez.programming.kicks-ass.net> <20200608163342.GA5155@infradead.org> <20200608164009.GD2531@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200608164009.GD2531@hirez.programming.kicks-ass.net> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 08, 2020 at 06:40:09PM +0200, Peter Zijlstra wrote: > There isn't one, it was meant to be used with static allocations. > > Frederic proposed changing all these to irq_work, and I think I'll go do > that. First dinner though. The irq_work API looks reasonable. What are the tradeoffs for smp_call_single_async vs irq_work?