Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Thu, 13 Dec 2018 11:27:03 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To:     Daniel Wang <wonderfly@google.com>
Cc:     Sasha Levin <sashal@kernel.org>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Petr Mladek <pmladek@suse.com>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        Steven Rostedt <rostedt@goodmis.org>, stable@vger.kernel.org,
        Alexander.Levin@microsoft.com,
        Andrew Morton <akpm@linux-foundation.org>,
        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 <mathieu.desnoyers@efficios.com>,
        Mel Gorman <mgorman@suse.de>, mhocko@kernel.org, pavel@ucw.cz,
        penguin-kernel@i-love.sakura.ne.jp,
        Peter Zijlstra <peterz@infradead.org>, tj@kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>, vbabka@suse.cz,
        Cong Wang <xiyou.wangcong@gmail.com>,
        Peter Feiner <pfeiner@google.com>
Subject: Re: 4.14 backport request for dbdda842fe96f: "printk: Add console
 owner and waiter logic to load balance console writes"
Message-ID: <20181213022703.GD4860@jagdpanzerIV>
References: <20181212081034.GA32687@jagdpanzerIV>
 <20181212133603.yyu2zvw7g454zdqd@pathway.suse.cz>
 <20181212135939.GA10170@tigerII.localdomain>
 <20181212174333.GC2746@sasha-vm>
 <CAJmjG2_zey77QxMzq997ALkD56d0UtHmGjF4dhq=TbEc2gox5A@mail.gmail.com>
 <20181212214337.GD2746@sasha-vm>
 <CAJmjG2_C0YRtVmNh2sg4JqhJJ11LMmbRHqwADxyO9CGh9ixQbA@mail.gmail.com>
 <20181212215225.GE2746@sasha-vm>
 <CAJmjG28s9bz51k=5i8eoKH2crj8e7-qM_EYWMqtUKZ_nGREQOg@mail.gmail.com>
 <CAJmjG29PnAfkUsU4PuVaFvjW-okO=U-MbHZHg7Sj_bBJ6EO09w@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAJmjG29PnAfkUsU4PuVaFvjW-okO=U-MbHZHg7Sj_bBJ6EO09w@mail.gmail.com>
User-Agent: Mutt/1.11.1 (2018-12-01)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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.

	-ss