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 7BBFEC4332F for ; Wed, 5 Oct 2022 01:14:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229565AbiJEBOK (ORCPT ); Tue, 4 Oct 2022 21:14:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41086 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229507AbiJEBOI (ORCPT ); Tue, 4 Oct 2022 21:14:08 -0400 Received: from mail-lj1-x236.google.com (mail-lj1-x236.google.com [IPv6:2a00:1450:4864:20::236]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8053A6DFA5 for ; Tue, 4 Oct 2022 18:14:06 -0700 (PDT) Received: by mail-lj1-x236.google.com with SMTP id bs18so15552750ljb.1 for ; Tue, 04 Oct 2022 18:14:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date; bh=ugwHEDQcF5VRN+4KCFZX1pbxbkZuWcWFPr79Ra+qDPI=; b=do+K2FKZlQ8TcKuvbRmDV+wUmqtG+O9ZHQ2AQs80qmIOF3Ndf/etuoxrXAtnR88Eky Ft1R3yunWStcGdXxedW6H3WxHi7Y/2LcCbQoKVvy910dO/gFWuk09itNyafbYYHEYC2n hpmlzZ172XZrdr7jpolEGuLd+0r3msrP3beff5UUfYD5WagkVQo3jjYD6tbqOdDp9OUP 3Icyu2nnxdmoT3XRlHybLzEv+A90HjV9D8HnSjYVUyPSQCBJGcl6DvmjsKEtJdo594RP 22ang0YRM72WZA/Yc+gPeJGqoMiOpNxSRfYSJmOyFPN8Bx7/oYERIqIIPKQRWEZ0Cu/K 6BhQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date; bh=ugwHEDQcF5VRN+4KCFZX1pbxbkZuWcWFPr79Ra+qDPI=; b=JdjatSD2TANmokP5axZuRoZ9tbEEEdjwjakQ2t61ub82vnHlkYsyqNYdMyZhnAOFcR 2vRXQB/CtHXrS08DynK/oU1V84lvw4bF2mS7JlD7sWV0jNjRaU38NP57/nzzXjQXLFdY uBMAOcmP3DNZrWllkbOYIS3a83g3vsriGCuDRKvVSfbRDZcoPWDvAdlU5vSpx03IIpsz f10yhsnY58kjyJTETSlWmBoXaJFCVZEwLuBcggKI7AtRw3gkoEitQEf+suNCT+Sa+vuH 0Zfnl7/LksSTJBPegucyLzLQDh5JmIvXJ/O+pXKgLV5syMYws0i1H+FzPPkaR2yWKUuO asKw== X-Gm-Message-State: ACrzQf0VrdYZ21zrZJrwdXTvNRx32je2xFcom/tUt5UVK1AGvlPm8Dx3 Ps8lhrevS56ga43be788C9zKd61sEOtVVwCBJMLV X-Google-Smtp-Source: AMsMyM4uwwNWAHUFkjOS8v4YCZr/nXwvqOlu921focmmgXpukWXHI/nXVpmmvFWPQ6QMi+fqImbpRUlKbxeRCgv7BC8= X-Received: by 2002:a05:651c:1546:b0:26d:9459:1a69 with SMTP id y6-20020a05651c154600b0026d94591a69mr9827913ljp.209.1664932444752; Tue, 04 Oct 2022 18:14:04 -0700 (PDT) MIME-Version: 1.0 References: <20221003232033.3404802-3-jstultz@google.com> <20221004013611.1822-1-hdanton@sina.com> <20221005002149.1876-1-hdanton@sina.com> In-Reply-To: <20221005002149.1876-1-hdanton@sina.com> From: John Stultz Date: Tue, 4 Oct 2022 18:13:52 -0700 Message-ID: Subject: Re: [RFC PATCH v4 2/3] sched: Avoid placing RT threads on cores handling long softirqs To: Hillf Danton Cc: LKML , linux-mm@kvack.org, "Connor O'Brien" , Qais Yousef , Peter Zijlstra , Steven Rostedt Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 4, 2022 at 5:22 PM Hillf Danton wrote: > On 3 Oct 2022 19:29:36 -0700 John Stultz > > > > Why would ksoftirqd preempt the rt task? > > > For example the kthread becomes sensitive to latency. Again, my apologies, I'm still not sure I am following. Could you expand a bit on the case you're concerned about? Is it the case where the ksoftirqd thread is configured to run at higher rtprio? thanks -john