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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4591EC433F5 for ; Wed, 5 Oct 2022 06:02:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A3FB06B0072; Wed, 5 Oct 2022 02:02:12 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9C8CE6B0073; Wed, 5 Oct 2022 02:02:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 868F36B0074; Wed, 5 Oct 2022 02:02:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 6FBA96B0072 for ; Wed, 5 Oct 2022 02:02:12 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 18121120636 for ; Wed, 5 Oct 2022 06:02:12 +0000 (UTC) X-FDA: 79985850504.06.2C0EE4A Received: from mail3-164.sinamail.sina.com.cn (mail3-164.sinamail.sina.com.cn [202.108.3.164]) by imf10.hostedemail.com (Postfix) with ESMTP id 20A82C0010 for ; Wed, 5 Oct 2022 06:02:09 +0000 (UTC) Received: from unknown (HELO localhost.localdomain)([114.249.58.228]) by sina.com (172.16.97.35) with ESMTP id 633D1D7C0000606E; Wed, 5 Oct 2022 14:00:30 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com X-SMAIL-MID: 3654215073696 From: Hillf Danton To: John Stultz Cc: LKML , linux-mm@kvack.org, "Connor O'Brien" , Qais Yousef , Peter Zijlstra , Steven Rostedt Subject: Re: [RFC PATCH v4 2/3] sched: Avoid placing RT threads on cores handling long softirqs Date: Wed, 5 Oct 2022 14:01:55 +0800 Message-Id: <20221005060155.1571-1-hdanton@sina.com> In-Reply-To: References: <20221003232033.3404802-3-jstultz@google.com> <20221004013611.1822-1-hdanton@sina.com> <20221005002149.1876-1-hdanton@sina.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1664949731; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=REopfdmG0YqGu2Mj6spxh/TE66SsVS/TIGKUPYd0HWE=; b=RWj5AHmTt/DNXzcCHWz0g9/egdnohT2hetNM3oI6i608sDK5ndaklOliWwm1ngye8v8+vc LCV9xZOkBm+VIFvVXxmhoiX15KUovrqMFHxn4QKECJKuzfIBdE9l6QNEWiEerTGpMmR5SK E1P6ZtRVvs6vAI/kG+GTJJVWKfrRI0U= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=none; spf=pass (imf10.hostedemail.com: domain of hdanton@sina.com designates 202.108.3.164 as permitted sender) smtp.mailfrom=hdanton@sina.com; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1664949731; a=rsa-sha256; cv=none; b=GKpAeKum6ZnIGKlrgxyCgp4K526oROVem8RgnxsqbrbhDW9psOMRsGEOqnrAU07On2PpQx fFOGWwyo6SStCfvWLq5WVc/YuZGZnOmcmDwtBs0DrER4PfzYDoDs1RdsRsvU89pSugcMii nCaL+RsLnmRF7mzGpZtAEl+T0RfKCf4= X-Stat-Signature: 1w6gzfxshr8sedbp747wnh1zqgn1epx7 X-Rspamd-Queue-Id: 20A82C0010 Authentication-Results: imf10.hostedemail.com; dkim=none; spf=pass (imf10.hostedemail.com: domain of hdanton@sina.com designates 202.108.3.164 as permitted sender) smtp.mailfrom=hdanton@sina.com; dmarc=none X-Rspamd-Server: rspam07 X-Rspam-User: X-HE-Tag: 1664949729-633748 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000002, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 4 Oct 2022 18:13:52 -0700 John Stultz > 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. > > Is it the case where > the ksoftirqd thread is configured to run at higher rtprio? > Yes, you are right.