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From: Petr Mladek <pmladek@suse.com>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	Dmitriy Vyukov <dvyukov@google.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Alexander Potapenko <glider@google.com>,
	Fengguang Wu <fengguang.wu@intel.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Will Deacon <will.deacon@arm.com>
Subject: Re: [PATCH v6 1/3] printk: Add line-buffered printk() API.
Date: Wed, 7 Nov 2018 12:45:20 +0100	[thread overview]
Message-ID: <20181107114520.bi3ur2fpn62rlyje@pathway.suse.cz> (raw)
In-Reply-To: <42f33aae-a1d1-197f-a1d5-8c5ec88e88d1@i-love.sakura.ne.jp>

On Wed 2018-11-07 19:52:53, Tetsuo Handa wrote:
> On 2018/11/06 23:35, Sergey Senozhatsky wrote:
> > - Do not allocate seq_buf if we are in printk-safe or in printk-nmi mode.
> >   To avoid "buffering for the sake of buffering". IOW, when in printk-safe
> >   use printk-safe.
> 
> Why? Since printk_safe_flush_buffer() forcibly flushes the partial line,
> calling printk_safe_log_store() after line buffering can reduce possibility of
> flushing partial lines, can't it?

Good point.

Well, printk_safe buffers are flushed via irqwork scheduled on the
same CPU. It might get flushed prematurely from other CPU but
I am not sure if this risk is worth the double buffering.

Best Regards,
Petr

  parent reply	other threads:[~2018-11-07 11:45 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-02 13:31 [PATCH v6 1/3] printk: Add line-buffered printk() API Tetsuo Handa
2018-11-02 13:31 ` [PATCH 2/3] mm: Use line-buffered printk() for show_free_areas() Tetsuo Handa
2018-11-07 14:07   ` Petr Mladek
2018-11-02 13:31 ` [PATCH 3/3] lockdep: Use line-buffered printk() for lockdep messages Tetsuo Handa
2018-11-02 13:36   ` Peter Zijlstra
2018-11-03  2:00     ` Tetsuo Handa
2018-11-06  8:38     ` Petr Mladek
2018-11-06  9:05       ` Sergey Senozhatsky
2018-11-06 12:57         ` Petr Mladek
2018-11-06  9:56       ` Tetsuo Handa
2018-11-07 15:19   ` Petr Mladek
2018-11-08  4:45     ` Sergey Senozhatsky
2018-11-08 11:37       ` Tetsuo Handa
2018-11-09  6:12         ` Sergey Senozhatsky
2018-11-09  9:55           ` Tetsuo Handa
2018-11-09 15:43             ` Petr Mladek
2018-11-10  2:42               ` Tetsuo Handa
2018-11-23 12:46                 ` Petr Mladek
2018-11-23 13:12                   ` Tetsuo Handa
2018-11-23 15:56                   ` Steven Rostedt
2018-11-24  0:24                     ` Tetsuo Handa
2018-11-26  4:34                       ` Sergey Senozhatsky
2018-11-28 13:29                     ` David Laight
2018-11-29 10:09                       ` Tetsuo Handa
2018-11-30 16:01                         ` Petr Mladek
2018-11-10  8:52               ` Tetsuo Handa
2018-11-23 12:52                 ` Petr Mladek
2018-11-09 14:08           ` Linus Torvalds
2018-11-09 14:42             ` Steven Rostedt
2018-11-08 11:53       ` Petr Mladek
2018-11-08 12:44         ` Sergey Senozhatsky
2018-11-08 14:21           ` Sergey Senozhatsky
2018-11-09  9:54     ` Tetsuo Handa
2018-11-02 14:40 ` [PATCH v6 1/3] printk: Add line-buffered printk() API Matthew Wilcox
2018-11-03  1:55   ` Tetsuo Handa
2018-11-02 18:12 ` kbuild test robot
2018-11-02 18:12   ` kbuild test robot
2018-11-06 14:35 ` Sergey Senozhatsky
2018-11-07 10:21   ` Petr Mladek
2018-11-07 12:54     ` Tetsuo Handa
2018-11-08  2:21     ` Sergey Senozhatsky
2018-11-08 11:24       ` Petr Mladek
2018-11-08 11:46         ` Tetsuo Handa
2018-11-08 12:30         ` Sergey Senozhatsky
2018-11-09 14:10           ` Petr Mladek
2018-11-12  7:59             ` Sergey Senozhatsky
2018-11-12 10:42               ` Tetsuo Handa
2018-11-17 10:14               ` Tetsuo Handa
2018-11-07 10:52   ` Tetsuo Handa
2018-11-07 11:01     ` David Laight
2018-11-07 12:00       ` Petr Mladek
2018-11-07 11:45     ` Petr Mladek [this message]
2018-11-08  2:30     ` Sergey Senozhatsky
2018-11-07 13:41 ` Petr Mladek
2018-11-07 14:06 ` Petr Mladek

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