Date: Fri, 8 Jun 2007 13:55:55 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Andreas Kleen <ak@suse.de>
Cc: "Keshavamurthy, Anil S" <anil.s.keshavamurthy@intel.com>,
       linux-kernel@vger.kernel.org, gregkh@suse.de, muli@il.ibm.com,
       asit.k.mallick@intel.com, suresh.b.siddha@intel.com,
       arjan@linux.intel.com, ashok.raj@intel.com, shaohua.li@intel.com,
       davem@davemloft.net
Subject: Re: [Intel-IOMMU 02/10] Library routine for pre-allocat pool
 handling
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On Fri, 8 Jun 2007 22:43:10 +0200 (CEST)
Andreas Kleen <ak@suse.de> wrote:

> > That's what kmem_cache_alloc() is for?!?!
> 
> Tradtionally that was not allowed in block layer path. Not sure
> it is fully obsolete with the recent dirty tracking work, probably not.
> 
> Besides it would need to be GFP_ATOMIC and the default
> atomic pools are not that big.

That in itself is a problem.  What do we have to do to be able
to make these allocations use the *much* stronger GFP_NOIO?

We could perhaps talk to Christoph about arranging for each slabcache to
have an optional private reserve page pool.  But fixing the GFP_ATOMIC
would be better.
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