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From: Stefan Roscher <ossrosch@linux.vnet.ibm.com>
To: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: fenkes@de.ibm.com, LKML <linux-kernel@vger.kernel.org>,
	LinuxPPC-Dev <linuxppc-dev@ozlabs.org>,
	raisch@de.ibm.com, alexschm@de.ibm.com,
	stefan.roscher@de.ibm.com
Subject: Re: [PATCH 1/3] IB/ehca: Replace vmalloc with kmalloc
Date: Tue, 28 Apr 2009 18:02:47 +0200	[thread overview]
Message-ID: <200904281802.47809.ossrosch@linux.vnet.ibm.com> (raw)
In-Reply-To: <1240931572.29485.77.camel@nimitz>

On Tuesday 28 April 2009 05:12:51 pm Dave Hansen wrote:
> On Tue, 2009-04-21 at 17:16 +0200, Stefan Roscher wrote:
> > From: Anton Blanchard <antonb at au1.ibm.com>
> > 
> > To improve performance of driver ressource allocation,
> > replace the vmalloc() call with kmalloc().
> 
> Just curious, but how big are these allocations?  Why was vmalloc() even
> ever used if we know they'll be small?
> 
> -- Dave
> 
> 

The theoretical maximum size can be 512k, but for common queue pairs 
less than 128k is used.Because of the theoretical maximum we implemented
vmalloc() first, but recognized a huge performance impact.

-- Stefan 

  reply	other threads:[~2009-04-28 16:02 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-21 15:16 [PATCH 1/3] IB/ehca: Replace vmalloc with kmalloc Stefan Roscher
2009-04-21 17:34 ` Roland Dreier
2009-04-22  9:11   ` Stefan Roscher
2009-04-22 14:02   ` Stefan Roscher
2009-04-22 14:10     ` michael
2009-04-22 16:00       ` Stefan Roscher
2009-04-22 16:12         ` michael
2009-04-28 13:07     ` [ewg] " Alexander Schmidt
2009-04-28 14:01       ` Roland Dreier
2009-04-28 14:13         ` Alexander Schmidt
2009-04-28 15:12 ` Dave Hansen
2009-04-28 16:02   ` Stefan Roscher [this message]
2009-04-28 16:45 ` Roland Dreier

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