Received: by 10.223.176.5 with SMTP id f5csp2247772wra; Thu, 8 Feb 2018 10:46:15 -0800 (PST) X-Google-Smtp-Source: AH8x227GVSSMy87S07x1UM6g0sFzVhZfXldSl4iPRICbugmg4gWxB3l8po9iH4bmdRKBeq5408nl X-Received: by 10.98.70.155 with SMTP id o27mr47887pfi.28.1518115575486; Thu, 08 Feb 2018 10:46:15 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1518115575; cv=none; d=google.com; s=arc-20160816; b=JHzrnf44RgfgPk5rzOqo/Hkwkmln/oNEGsTciYny4FLTlhYq/ylc+T43PJ7m2Rkp9o 11E5cBfcwO2UnAO2wawmB9B+aXqvZ4oqRnMhr3TOf3GN/yasjmvK2nDJWUemf+r95agK W5OXNBhCSx099uvbp1FvQAYCbXhcRZs4kLMjyiyL0TXsF4jdfIiB/2QU2gai1p+LGQ3T 5xm2Me+JHdoxBNE6ziIyz0A3duc4y6QNBeZjqhyZRcLgOQDXONpGfCKm50HeZCwZAIFm jPnMECFzXPYfxd7qw/LnGNZ3iSfxSI+qg5/j+eyxH9Mx3U90N3PXsL0mH+83TiDtaQA3 Marg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:from:subject:cc:to:message-id:date :arc-authentication-results; bh=cjmBBglnXYRf9u2TK3GXoGB5G8XyjBw5rZ25fWyCYVM=; b=ReAHPYI1oksgzdFEOuCwFcFotupZdeAsswbmjD/hFbgyEEBf1n3RJXX3Tdq6m8A2iC /2p6DYuppspOMpCHuVrv6VUbwv3nB+i+b3QUy5i5AIywtC+hY3pTVOPdBBJgEzNYuNdq 5WcdQbOv8fIH72uSD2xnoHpIkGjBreWtA1iO7PnRs3aEQyt0iuzBBUXJz3CuzaGDU6+K m3407GASrkhvXDrCd88TJzAPwu6dwlaH42cDQwJ5bqm6bktPPXO2Jh55wEF0HXdsQots F7Tgfp1J5Rr5ECqA425JWlgweqjGDVsZMqgctKqOcz6xZb23HDjv73ud2G40T3hsuOy8 DcAg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id t22-v6si316784plo.256.2018.02.08.10.45.58; Thu, 08 Feb 2018 10:46:15 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752166AbeBHSpM (ORCPT + 99 others); Thu, 8 Feb 2018 13:45:12 -0500 Received: from shards.monkeyblade.net ([184.105.139.130]:47862 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751094AbeBHSpL (ORCPT ); Thu, 8 Feb 2018 13:45:11 -0500 Received: from localhost (67.110.78.66.ptr.us.xo.net [67.110.78.66]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 6315D11D698C4; Thu, 8 Feb 2018 10:45:09 -0800 (PST) Date: Thu, 08 Feb 2018 13:45:06 -0500 (EST) Message-Id: <20180208.134506.1374787894560277876.davem@davemloft.net> To: bigeasy@linutronix.de Cc: frederic@kernel.org, linux-kernel@vger.kernel.org, alexander.levin@verizon.com, peterz@infradead.org, mchehab@s-opensource.com, torvalds@linux-foundation.org, hannes@stressinduktion.org, paulmck@linux.vnet.ibm.com, wanpeng.li@hotmail.com, dima@arista.com, tglx@linutronix.de, akpm@linux-foundation.org, pabeni@redhat.com, rrendec@arista.com, mingo@kernel.org, sgruszka@redhat.com, riel@redhat.com, edumazet@google.com Subject: Re: [RFC PATCH 2/4] softirq: Per vector deferment to workqueue From: David Miller In-Reply-To: <20180208174450.qjvjy752jf4ngt2g@breakpoint.cc> References: <1516376774-24076-1-git-send-email-frederic@kernel.org> <1516376774-24076-3-git-send-email-frederic@kernel.org> <20180208174450.qjvjy752jf4ngt2g@breakpoint.cc> X-Mailer: Mew version 6.7 on Emacs 25.3 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Thu, 08 Feb 2018 10:45:10 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sebastian Andrzej Siewior Date: Thu, 8 Feb 2018 18:44:52 +0100 > May I instead suggest to stick to ksoftirqd? So you run in softirq > context (after return from IRQ) and if takes too long, you offload the > vector to ksoftirqd instead. You may want to play with the metric on > which you decide when you want switch to ksoftirqd / account how long a > vector runs. Having read over this stuff for the past few weeks this is how I feel as well. Just make ksofbitrq do what we want (only execute the overloaded softirq vectors). The more I look at the workqueue stuff, the more complications and weird behavioral artifacts we are getting for questionable gain.