From: "Luis R. Rodriguez" <mcgrof@suse.com>
To: Vinson Lee <vlee@twopensource.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Michal Hocko <mhocko@suse.cz>,
Josh Triplett <josh@joshtriplett.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Fabian Frederick <fabf@skynet.be>,
Bertrand Jacquin <beber@meleeweb.net>,
Andy Lutomirski <luto@amacapital.net>,
Pranith Kumar <bobby.prani@gmail.com>,
Peter Foley <pefoley2@pefoley.com>,
Clark Williams <clark.williams@gmail.com>,
Mel Gorman <mgorman@suse.de>,
linux-kernel@vger.kernel.org, Nate Stahl <stahl@twitter.com>,
Vinson Lee <vlee@twitter.com>
Subject: Re: [PATCH] Increase maximum size of dmesg buffer to 16MB.
Date: Fri, 12 Dec 2014 23:45:15 +0100 [thread overview]
Message-ID: <20141212224515.GU25677@wotan.suse.de> (raw)
In-Reply-To: <1418423906-5461-1-git-send-email-vlee@twopensource.com>
On Fri, Dec 12, 2014 at 02:38:26PM -0800, Vinson Lee wrote:
> From: Nate Stahl <stahl@twitter.com>
>
> A full task stack dump of all tasks on a machine can generate more than
> 4MB of output to dmesg. Dumping this data to the serial console causes
> the machine to hang for a number of minutes (an unacceptable impact),
> but dumping the same data to memory is feasible if the dmesg buffer is
> sized large enough to hold the output. Set to 16MB which will hopefully
> be large enough to handle a dump from any of our servers at this time.
>
> Signed-off-by: Nate Stahl <stahl@twitter.com>
> Signed-off-by: Vinson Lee <vlee@twitter.com>
Isn't this the perpetual issue of having large number of CPUs? If so
consider use of LOG_CPU_MAX_BUF_SHIFT instead, otherwise clarifying how
this would be a different issue would be good. LOG_CPU_MAX_BUF_SHIFT
should scale nicely but you can increase it as well, is it being used?
Luis
next prev parent reply other threads:[~2014-12-12 22:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-12 22:38 Vinson Lee
2014-12-12 22:45 ` Luis R. Rodriguez [this message]
2014-12-12 23:07 ` Vinson Lee
2014-12-12 23:29 ` Luis R. Rodriguez
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