From: Andrew Morton <akpm@linux-foundation.org>
To: Jan Kara <jack@suse.cz>
Cc: LKML <linux-kernel@vger.kernel.org>,
mhocko@suse.cz, hare@suse.de,
Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH 0/4 v6] Avoid softlockups in console_unlock()
Date: Wed, 21 Aug 2013 14:27:23 -0700 [thread overview]
Message-ID: <20130821142723.5fd8c0b0062b35ee83a68dcc@linux-foundation.org> (raw)
In-Reply-To: <1377072512-7986-1-git-send-email-jack@suse.cz>
On Wed, 21 Aug 2013 10:08:28 +0200 Jan Kara <jack@suse.cz> wrote:
> These patches avoid softlockups when a CPU gets caught in console_unlock() for
> a long time during heavy printing from other CPU. As is discussed in patch 3/4
> it isn't enough to just silence the watchdog because if CPU spends too long in
> console_unlock() also RCU will complain, other CPUs can be blocked waiting for
> printing CPU to process IPI, and even disk can be offlined because commands
> couldn't be delivered to it for too long.
>
> This patch series solves the problem by stopping printing in console_unlock()
> after 1000 characters and the printing is postponed to irq work. To avoid
> hogging a single CPU (irq work gets processed on the same CPU where it was
> queued so it doesn't really help to reduce the printing load on that CPU) we
> introduce a new type of lazy irq work - IRQ_WORK_UNBOUND - which can be
> processed by any CPU.
I still hate the patchset :(
Remind us why we need this? Whose kernel is spewing so much logging and why?
next prev parent reply other threads:[~2013-08-21 21:27 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-21 8:08 Jan Kara
2013-08-21 8:08 ` [PATCH 1/4] printk: Remove separate printk_sched buffers and use printk buf instead Jan Kara
2013-08-21 8:08 ` [PATCH 2/4] irq_work: Provide a irq work that can be processed on any cpu Jan Kara
2013-08-21 18:49 ` Steven Rostedt
2013-09-05 15:56 ` Jan Kara
2013-08-21 8:08 ` [PATCH 3/4] printk: Defer printing to irq work when we printed too much Jan Kara
2013-08-21 19:06 ` Steven Rostedt
2013-08-21 8:08 ` [PATCH 4/4] printk: Use unbound irq work for printing and waking Jan Kara
2013-08-21 19:24 ` Steven Rostedt
2013-08-21 21:27 ` Andrew Morton [this message]
2013-08-21 22:59 ` [PATCH 0/4 v6] Avoid softlockups in console_unlock() Jan Kara
2013-08-22 19:49 ` Andrew Morton
2013-08-22 21:57 ` Jan Kara
2013-08-22 22:14 ` Andrew Morton
2013-08-23 19:50 ` Jiri Kosina
2013-08-23 19:48 ` Jiri Kosina
2013-08-23 19:58 ` Andrew Morton
2013-08-26 11:48 ` Jiri Kosina
2013-09-05 15:46 ` Jan Kara
2013-09-19 21:26 ` Andrew Morton
2013-09-20 21:55 ` Jan Kara
2013-11-07 21:48 Jan Kara
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