From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) by kanga.kvack.org (Postfix) with ESMTP id 5B7A28E0161 for ; Thu, 13 Dec 2018 04:59:36 -0500 (EST) Received: by mail-ed1-f70.google.com with SMTP id s50so891543edd.11 for ; Thu, 13 Dec 2018 01:59:36 -0800 (PST) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id t17-v6si253791ejg.184.2018.12.13.01.59.34 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 13 Dec 2018 01:59:34 -0800 (PST) Date: Thu, 13 Dec 2018 10:59:31 +0100 From: Petr Mladek Subject: Re: 4.14 backport request for dbdda842fe96f: "printk: Add console owner and waiter logic to load balance console writes" Message-ID: <20181213095931.24qovurhtpa3jxzl@pathway.suse.cz> References: <20181212135939.GA10170@tigerII.localdomain> <20181212174333.GC2746@sasha-vm> <20181212214337.GD2746@sasha-vm> <20181212215225.GE2746@sasha-vm> <20181213022703.GD4860@jagdpanzerIV> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Daniel Wang Cc: Sergey Senozhatsky , Sasha Levin , Sergey Senozhatsky , Steven Rostedt , stable@vger.kernel.org, Alexander.Levin@microsoft.com, Andrew Morton , byungchul.park@lge.com, dave.hansen@intel.com, hannes@cmpxchg.org, jack@suse.cz, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mathieu Desnoyers , Mel Gorman , mhocko@kernel.org, pavel@ucw.cz, penguin-kernel@i-love.sakura.ne.jp, Peter Zijlstra , tj@kernel.org, Linus Torvalds , vbabka@suse.cz, Cong Wang , Peter Feiner On Wed 2018-12-12 18:39:42, Daniel Wang wrote: > > Additionally, for dbdda842fe96f to work as expected we really > need fd5f7cde1b85d4c. Otherwise printk() can schedule under > console_sem and console_owner, which will deactivate the "load > balance" logic. > > It looks like fd5f7cde1b85d4c got into 4.14.82 that was released last month. > > On Wed, Dec 12, 2018 at 6:27 PM Sergey Senozhatsky > wrote: > > > > On (12/12/18 16:40), Daniel Wang wrote: > > > In case this was buried in previous messages, the commit I'd like to > > > get backported to 4.14 is dbdda842fe96f: printk: Add console owner and > > > waiter logic to load balance console writes. But another followup > > > patch that fixes a bug in that patch is also required. That is > > > c14376de3a1b: printk: Wake klogd when passing console_lock owner. > > > > Additionally, for dbdda842fe96f to work as expected we really > > need fd5f7cde1b85d4c. Otherwise printk() can schedule under > > console_sem and console_owner, which will deactivate the "load > > balance" logic. To make it clear. Please, make sure that the following commits are backported together: + dbdda842fe96f8932ba ("printk: Add console owner and waiter logic to load balance console writes") + c162d5b4338d72deed6 ("printk: Hide console waiter logic into helpers") + fd5f7cde1b85d4c8e09 ("printk: Never set console_may_schedule in console_trylock()") + c14376de3a1befa70d9 ("printk: Wake klogd when passing console_lock owner") I generated this list from git log using "Fixes:" tag. It seems to mention all commits dicussed above. Best Regards, Petr