linux-kernel - Re: [RT LATENCY] 249 microsecond latency caused by slub's unfreeze

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Date:	Wed, 27 Mar 2013 11:59:57 +0900
From:	Joonsoo Kim <iamjoonsoo.kim@....com>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	Christoph Lameter <cl@...ux.com>,
	LKML <linux-kernel@...r.kernel.org>,
	RT <linux-rt-users@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Clark Williams <clark@...hat.com>
Subject: Re: [RT LATENCY] 249 microsecond latency caused by slub's
 unfreeze_partials() code.

On Mon, Mar 25, 2013 at 02:32:35PM -0400, Steven Rostedt wrote:
> On Mon, 2013-03-25 at 18:27 +0000, Christoph Lameter wrote:
> > On Mon, 25 Mar 2013, Steven Rostedt wrote:
> > 
> > > If this makes it more deterministic, and lower worse case latencies,
> > > then it's definitely worth the price.
> > 
> > Yes that would make it more deterministic. Maybe I should add an option
> > to be able to compile the allocator without cpu partial page support?
> 
> I agree that would be useful.

Hello, Steven and Christoph.

How about using spin_try_lock() in unfreeze_partials() and
using spin_lock_contented() in get_partial_node() to reduce latency?
IMHO, this doesn't make code more deterministic, but can maintain
a benefit of cpu partial page with tolerable latency.

Thanks.

> 
> -- Steve
> 
> 
> --
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