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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 0B0BBC4332D for ; Tue, 26 Jan 2021 18:06:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BDADC22240 for ; Tue, 26 Jan 2021 18:06:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404027AbhAZSFx (ORCPT ); Tue, 26 Jan 2021 13:05:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390980AbhAZJYr (ORCPT ); Tue, 26 Jan 2021 04:24:47 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF78AC061573 for ; Tue, 26 Jan 2021 01:24:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=+OtfEgx/CrQms/KzxhC+8LI0oesZp6YvKvcU/ZJAXaQ=; b=PM/ThATZ3HRwA0ToVGZUIwtiqu JpPVhiFCUsfvHKhkqHld9mxA8onxAtSGanyP4POw/e3rhs2HdtfiuFL6vlkQdwT2CIb9aYBO6uFI/ 8Sp2qciNI2sjIbNYtFDfUL7x/ymvJ4KDyzVnC4qNxj9tJIvFXf9ezbPXLH+Ri9SjCb2BOsq03gnUX BjL42J/HCYfiYSq5uiGmTJ410/hUbV8qS4XiJ0zCwJmnM3BSTxUWiz1m3065qMlrREwEMW+DoT4IW AkH0GBrDBLv+oob5veZ1+sA2vXQT7MaIXrCX6sw4wCxe+YW7vxE8m+wxBy+nNfzCThe1uT9UQFxGc oHk2YQyw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1l4KYj-005M7q-Eq; Tue, 26 Jan 2021 09:23:09 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id AE52D300DB4; Tue, 26 Jan 2021 10:22:48 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 8343420297EDB; Tue, 26 Jan 2021 10:22:48 +0100 (CET) Date: Tue, 26 Jan 2021 10:22:48 +0100 From: Peter Zijlstra To: "Zhang, Qiang" Cc: "tglx@linutronix.de" , "linux-kernel@vger.kernel.org" Subject: Re: Question on migrate_disabe/enable() Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 26, 2021 at 02:12:45AM +0000, Zhang, Qiang wrote: > Hello Peterz, tglx > > I have some questions about migrate_disabe/enable(), in the past > migrate_disabe/enable() is replaced by preempt_disable/enable() in no > RT system. > > And now migrate_disabe/enable() has its own implementation, I want to > know in migrate_disabe/enable() critical area is blocking allowed? Yes, obviously. Otherwise it would've been preempt_disable(). > If allowed, There's a blockage in migrate_disabe/enable() critical > area, and this time if CPU going offline，offline time will be longer. > Is this normal phenomenon？ Ofcourse.