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From: Matt Mackall <mpm@selenic.com>
To: Christoph Lameter <clameter@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Pekka Enberg <penberg@cs.helsinki.fi>,
	Hugh Dickins <hugh@veritas.com>, Andi Kleen <andi@firstfloor.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] procfs: provide slub's /proc/slabinfo
Date: Fri, 04 Jan 2008 16:30:18 -0600	[thread overview]
Message-ID: <1199485818.3821.46.camel@cinder.waste.org> (raw)
In-Reply-To: <Pine.LNX.4.64.0801041321490.12189@schroedinger.engr.sgi.com>


On Fri, 2008-01-04 at 13:36 -0800, Christoph Lameter wrote:
> Ok. So lets try a worst case scenario. If we do a 128 byte kmalloc
> then we 
> can allocate the following number of object from one 4k slab
> 
> SLUB 32	    (all memory of the 4k page is used for 128 byte objects)
> SLAB 29/30  (management structure occupies first two/three objects)
> SLOB 30(?)  (Alignment results in object being 136 byte of effective size,
> 		we have 16 bytes leftover that could be used for a
> 		very small allocation. Right?)

Don't know how you got to 136, the minimum alignment is 4 on x86. But I
already said in my last email that SLUB would win for the special case
of power of two allocations. But as long as we're looking at worst
cases, let's consider an alloc of 257 bytes..

SLUB  8 (1016 bytes wasted)
SLOB 15 (105 bytes wasted, with 136 bytes still usable)

Can we be done with this now, please?

-- 
Mathematics is the supreme nostalgia of our time.


  reply	other threads:[~2008-01-04 22:31 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-02 18:43 Hugh Dickins
2008-01-02 18:53 ` Christoph Lameter
2008-01-02 19:09 ` Pekka Enberg
2008-01-02 19:35   ` Linus Torvalds
2008-01-02 19:45     ` Linus Torvalds
2008-01-02 19:49     ` Pekka Enberg
2008-01-02 22:50     ` Matt Mackall
2008-01-03  8:52       ` Ingo Molnar
2008-01-03 16:46         ` Matt Mackall
2008-01-04  2:21           ` Christoph Lameter
2008-01-04  2:45             ` Andi Kleen
2008-01-04  4:34               ` Matt Mackall
2008-01-04  9:17               ` Peter Zijlstra
2008-01-04 20:37                 ` Christoph Lameter
2008-01-04  4:11             ` Matt Mackall
2008-01-04 20:34               ` Christoph Lameter
2008-01-04 20:55                 ` Matt Mackall
2008-01-04 21:36                   ` Christoph Lameter
2008-01-04 22:30                     ` Matt Mackall [this message]
2008-01-05 20:16                       ` Christoph Lameter
2008-01-05 16:21               ` Pekka J Enberg
2008-01-05 17:14                 ` Andi Kleen
2008-01-05 20:05                 ` Christoph Lameter
2008-01-07 20:12                   ` Pekka J Enberg
2008-01-06 17:51                 ` Matt Mackall
2008-01-07 18:06                   ` Pekka J Enberg
2008-01-07 19:03                     ` Matt Mackall
2008-01-07 19:53                       ` Pekka J Enberg
2008-01-07 20:44                       ` Pekka J Enberg
2008-01-10 10:04                       ` Pekka J Enberg
2008-01-09 19:15                     ` [RFC PATCH] greatly reduce SLOB external fragmentation Matt Mackall
2008-01-09 22:43                       ` Pekka J Enberg
2008-01-09 22:59                         ` Matt Mackall
2008-01-10 10:02                           ` Pekka J Enberg
2008-01-10 10:54                             ` Pekka J Enberg
2008-01-10 15:44                               ` Matt Mackall
2008-01-10 16:13                               ` Linus Torvalds
2008-01-10 17:49                                 ` Matt Mackall
2008-01-10 18:28                                   ` Linus Torvalds
2008-01-10 18:42                                     ` Matt Mackall
2008-01-10 19:24                                       ` Christoph Lameter
2008-01-10 19:44                                         ` Matt Mackall
2008-01-10 19:51                                           ` Christoph Lameter
2008-01-10 19:41                                       ` Linus Torvalds
2008-01-10 19:46                                         ` Christoph Lameter
2008-01-10 19:53                                         ` Andi Kleen
2008-01-10 19:52                                           ` Christoph Lameter
2008-01-10 19:16                                   ` Christoph Lameter
2008-01-10 19:23                                     ` Matt Mackall
2008-01-10 19:31                                       ` Christoph Lameter
2008-01-10 21:25                                   ` Jörn Engel
2008-01-10 18:13                                 ` Andi Kleen
2008-07-30 21:51                                 ` Pekka J Enberg
2008-07-30 22:00                                   ` Linus Torvalds
2008-07-30 22:22                                     ` Pekka Enberg
2008-07-30 22:35                                       ` Linus Torvalds
2008-07-31  0:42                                         ` malc
2008-07-31  1:03                                         ` Matt Mackall
2008-07-31  1:09                                     ` Matt Mackall
2008-07-31 14:11                                       ` Andi Kleen
2008-07-31 15:25                                         ` Christoph Lameter
2008-07-31 16:03                                           ` Andi Kleen
2008-07-31 16:05                                             ` Christoph Lameter
2008-07-31 14:26                                       ` Christoph Lameter
2008-07-31 15:38                                         ` Matt Mackall
2008-07-31 15:42                                           ` Christoph Lameter
2008-01-10  2:46                         ` Matt Mackall
2008-01-10 10:03                       ` Pekka J Enberg
2008-01-03 20:31         ` [PATCH] procfs: provide slub's /proc/slabinfo Christoph Lameter

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