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Message-ID: <43FBB292.1000304@yahoo.com.au>
Date: Wed, 22 Feb 2006 11:38:42 +1100
From: Nick Piggin <nickpiggin@yahoo.com.au>
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To: David Gibson <dwg@au1.ibm.com>
CC: William Lee Irwin <wli@holomorphy.com>, linux-kernel@vger.kernel.org
Subject: Re: RFC: Block reservation for hugetlbfs
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David Gibson wrote:
> On Tue, Feb 21, 2006 at 03:18:59PM +1100, Nick Piggin wrote:

>>This introduces
>>tree_lock(r) -> hugetlb_lock
>>
>>And we already have
>>hugetlb_lock -> lru_lock
>>
>>So we now have tree_lock(r) -> lru_lock, which would deadlock
>>against lru_lock -> tree_lock(w), right?
>>
>>From a quick glance it looks safe, but I'd _really_ rather not
>>introduce something like this.
> 
> 
> Urg.. good point.  I hadn't even thought of that consequence - I was
> more worried about whether I need i_lock or i_mutex to protect my
> updates to i_blocks.
> 
> Would hugetlb_lock -> tree_lock(r) be any preferable (I think that's a
> possible alternative).
> 

Yes I think that should avoid the introduction of new lock dependency.

-- 
SUSE Labs, Novell Inc.
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