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Date: Tue, 3 Feb 2009 20:42:04 +0200
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Subject: Re: [patch] SLQB slab allocator
From: Pekka Enberg <penberg@cs.helsinki.fi>
To: Christoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>, Nick Piggin <npiggin@suse.de>,
       "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>,
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Hi Christoph,

On Tue, Feb 3, 2009 at 7:33 PM, Christoph Lameter
<cl@linux-foundation.org> wrote:
>> > Trimming through water marks and allocating memory from the page allocator
>> > is going to be very frequent if you continually allocate on one processor
>> > and free on another.
>>
>> Um yes, that's the point. But you previously claimed that it would just
>> grow unconstrained. Which is obviously wrong. So I don't understand what
>> your point is.
>
> It will grow unconstrained if you elect to defer queue processing. That
> was what we discussed.

Well, the slab_hiwater() check in __slab_free() of mm/slqb.c will cap
the size of the queue. But we do the same thing in SLAB with
alien->limit in cache_free_alien() and ac->limit in __cache_free(). So
I'm not sure what you mean when you say that the queues will "grow
unconstrained" (in either of the allocators). Hmm?

                               Pekka