linux-kernel - Re: [this_cpu_xx V5 19/19] SLUB: Experimental new fastpath w/o interrupt disable

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Date:	Thu, 8 Oct 2009 08:44:56 -0400
From:	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Christoph Lameter <cl@...ux-foundation.org>,
	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
	Pekka Enberg <penberg@...helsinki.fi>,
	Tejun Heo <tj@...nel.org>, Mel Gorman <mel@....ul.ie>,
	mingo@...e.hu
Subject: Re: [this_cpu_xx V5 19/19] SLUB: Experimental new fastpath w/o
	interrupt disable

* Peter Zijlstra (peterz@...radead.org) wrote:
> On Wed, 2009-10-07 at 11:21 -0400, Christoph Lameter wrote:
> > On Wed, 7 Oct 2009, Mathieu Desnoyers wrote:
> > 
> > > You are already calling the scheduler when ending the _fast_ path. I
> > > don't see the problem with calling it when you end the slow path
> > > execution.
> > 
> > Well yes that gives rise to the thought of using
> > 
> > 	preempt_enable_no_sched()
> 
> NACK, delaying the reschedule is not an option

Even if only done with interrupt off, and check resched is called after
each irq enable following this critical section ? I'd like to understand
the reason behind your rejection for this specific case.

Thanks,

Mathieu

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
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