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Date: Sun, 28 Oct 2007 19:59:27 -0700 (PDT)
From: Christoph Lameter <clameter@sgi.com>
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To: Pekka J Enberg <penberg@cs.helsinki.fi>
cc: Matthew Wilcox <matthew@wil.cx>, akpm@linux-foundation.org,
       linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [patch 08/10] SLUB: Optional fast path using cmpxchg_local
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On Sun, 28 Oct 2007, Pekka J Enberg wrote:

> Can you please write a comment of the locking rules when cmpxchg_local() 
> is used? Looks as if we could push that local_irq_save() to slub_lock() 
> and local_irq_restore() to slub_unlock() and deal with the unused flags 
> variable for the non-CONFIG_FAST_CMPXCHG_LOCAL case with a macro, no?

Hmmmm... Maybe .. The locking rules are not changed at all by this patch. 
The cmpxchg_local is only used for the per cpu object list. The per cpu 
slabs are frozen.