Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753397AbdLNUkk (ORCPT ); Thu, 14 Dec 2017 15:40:40 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:49032 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752805AbdLNUkh (ORCPT ); Thu, 14 Dec 2017 15:40:37 -0500 Date: Thu, 14 Dec 2017 12:40:35 -0800 From: Andrew Morton To: Anshuman Khandual Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, mhocko@suse.com Subject: Re: [PATCH V3] mm/mprotect: Add a cond_resched() inside change_pmd_range() Message-Id: <20171214124035.e77706f0a314f2082a2d1b7c@linux-foundation.org> In-Reply-To: <20171214140551.5794-1-khandual@linux.vnet.ibm.com> References: <20171214140551.5794-1-khandual@linux.vnet.ibm.com> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 427 Lines: 10 On Thu, 14 Dec 2017 19:35:51 +0530 Anshuman Khandual wrote: > While testing on a large CPU system, detected the following RCU > stall many times over the span of the workload. This problem > is solved by adding a cond_resched() in the change_pmd_range() > function. > > [ 850.962530] INFO: rcu_sched detected stalls on CPUs/tasks: That's a bit rude. I think I'll add a cc:stable to this one.