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Date: Thu, 12 Jun 2014 16:56:38 +0900
From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
To: Minchan Kim <minchan@kernel.org>
Subject: Re: [PATCH v2 10/10] mm, cma: use spinlock instead of mutex
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Cc: kvm-ppc@vger.kernel.org, Russell King - ARM Linux <linux@arm.linux.org.uk>,
 kvm@vger.kernel.org, Gleb Natapov <gleb@kernel.org>,
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 "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
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On Thu, Jun 12, 2014 at 04:40:29PM +0900, Minchan Kim wrote:
> On Thu, Jun 12, 2014 at 12:21:47PM +0900, Joonsoo Kim wrote:
> > Currently, we should take the mutex for manipulating bitmap.
> > This job may be really simple and short so we don't need to sleep
> > if contended. So I change it to spinlock.
> 
> I'm not sure it would be good always.
> Maybe you remember we discussed about similar stuff about bitmap
> searching in vmap friend internally, which was really painful
> when it was fragmented. So, at least we need number if you really want
> and I hope the number from ARM machine most popular platform for CMA
> at the moment.

Good Point!! Agreed. I will drop this one in next spin and re-submit
in separate patchset after some testing.

Thanks.