From mboxrd@z Thu Jan  1 00:00:00 1970
Subject: Re: [git pull] more SLUB updates for 2.6.25
References: <Pine.LNX.4.64.0802071755580.7473@schroedinger.engr.sgi.com>
	<200802081812.22513.nickpiggin@yahoo.com.au>
	<47AC04CD.9090407@cosmosbay.com>
From: Andi Kleen <andi@firstfloor.org>
Date: 08 Feb 2008 15:58:05 +0100
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To: Eric Dumazet <dada1@cosmosbay.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>, Christoph Lameter <clameter@sgi.com>, Linus Torvalds <torvalds@linux-foundation.org>, Andrew Morton <akpm@linux-foundation.org>, LKML <linux-kernel@vger.kernel.org>, linux-mm@kvack.org
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Eric Dumazet <dada1@cosmosbay.com> writes:
> 
> What about IRQ masking then ?
> 
> Many CPU pay high cost for cli/sti pair...

Many? In the x86 world only P4. On the other cores cli/sti (and even
pushf ; cli ; popf) is reasonably fast.

> 
> And SLAB/SLUB allocators, even if only used from process context, want
> to disable/re-enable interrupts...
> 
> I understand kmalloc() want generic pools, but dedicated pools could
> avoid this cli/sti

While there are a lot of P4s around they are obsolete by now and I would
advise against major redesigns for tuning obsolete CPUs.

-Andi

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