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From: Matt Mackall <mpm@selenic.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>, Christoph Lameter <clameter@sgi.com>,
	linux-kernel@vger.kernel.org, linux-mm@vger.kernel.org,
	suresh.b.siddha@intel.com, corey.d.gough@intel.com,
	Pekka Enberg <penberg@cs.helsinki.fi>
Subject: Re: [patch 09/10] Remove the SLOB allocator for 2.6.23
Date: Mon, 9 Jul 2007 16:57:24 -0500	[thread overview]
Message-ID: <20070709215724.GV11115@waste.org> (raw)
In-Reply-To: <20070708110224.9cd9df5b.akpm@linux-foundation.org>

On Sun, Jul 08, 2007 at 11:02:24AM -0700, Andrew Morton wrote:
> Guys, look at this the other way.  Suppose we only had slub, and someone
> came along and said "here's a whole new allocator which saves 4.5k of
> text", would we merge it on that basis?  Hell no, it's not worth it.  What
> we might do is to get motivated to see if we can make slub less porky under
> appropriate config settings.

Well I think we would obviously throw out SLAB and SLUB if they
weren't somewhat faster than SLOB. They're much more problematic and
one of the big features that Christoph's pushing is a fix for a
problem that SLOB simply doesn't have: huge numbers of SLAB/SLUB pages
being held down by small numbers of objects. 

> Let's not get sentimental about these things: in general, if there's any
> reasonable way in which we can rid ourselves of any code at all, we should
> do so, no?

I keep suggesting a Voyager Replacement Fund, but James isn't
interested.

But seriously, I don't think it should be at all surprising that the
allocator that's most appropriate for machines with < 32MB of RAM is
different than the one for machines with > 1TB of RAM.

The maintenance overhead of SLOB is fairly minimal. The biggest
outstanding SLOB problem is nommu's rather broken memory size
reporting.

-- 
Mathematics is the supreme nostalgia of our time.

  parent reply	other threads:[~2007-07-09 21:57 UTC|newest]

Thread overview: 86+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-07-08  3:49 [patch 00/10] [RFC] SLUB patches for more functionality, performance and maintenance Christoph Lameter
2007-07-08  3:49 ` [patch 01/10] SLUB: Direct pass through of page size or higher kmalloc requests Christoph Lameter
2007-07-08  3:49 ` [patch 02/10] SLUB: Avoid page struct cacheline bouncing due to remote frees to cpu slab Christoph Lameter
2007-07-08  3:49 ` [patch 03/10] SLUB: Do not use page->mapping Christoph Lameter
2007-07-08  3:49 ` [patch 04/10] SLUB: Move page->offset to kmem_cache_cpu->offset Christoph Lameter
2007-07-08  3:49 ` [patch 05/10] SLUB: Avoid touching page struct when freeing to per cpu slab Christoph Lameter
2007-07-08  3:49 ` [patch 06/10] SLUB: Place kmem_cache_cpu structures in a NUMA aware way Christoph Lameter
2007-07-08  3:49 ` [patch 07/10] SLUB: Optimize cacheline use for zeroing Christoph Lameter
2007-07-08  3:50 ` [patch 08/10] SLUB: Single atomic instruction alloc/free using cmpxchg Christoph Lameter
2007-07-08  3:50 ` [patch 09/10] Remove the SLOB allocator for 2.6.23 Christoph Lameter
2007-07-08  7:51   ` Ingo Molnar
2007-07-08  9:43     ` Nick Piggin
2007-07-08  9:54       ` Ingo Molnar
2007-07-08 10:23         ` Nick Piggin
2007-07-08 10:42           ` Ingo Molnar
2007-07-08 18:02     ` Andrew Morton
2007-07-09  2:57       ` Nick Piggin
2007-07-09 11:04         ` Pekka Enberg
2007-07-09 11:16           ` Nick Piggin
2007-07-09 12:47             ` Pekka Enberg
2007-07-09 13:46             ` Pekka J Enberg
2007-07-09 16:08           ` Christoph Lameter
2007-07-10  8:17             ` Pekka J Enberg
2007-07-10  8:27               ` Nick Piggin
2007-07-10  9:31                 ` Pekka Enberg
2007-07-10 10:09                   ` Nick Piggin
2007-07-10 12:02                   ` Matt Mackall
2007-07-10 12:57                     ` Pekka J Enberg
2007-07-10 22:12                     ` Christoph Lameter
2007-07-10 22:40                       ` Matt Mackall
2007-07-10 22:50                         ` Christoph Lameter
2007-07-09 16:06         ` Christoph Lameter
2007-07-09 16:51           ` Andrew Morton
2007-07-09 17:26             ` Christoph Lameter
2007-07-09 18:00               ` Andrew Morton
2007-07-10  1:43               ` Nick Piggin
2007-07-10  1:56                 ` Christoph Lameter
2007-07-10  2:02                   ` Nick Piggin
2007-07-10  2:11                     ` Christoph Lameter
2007-07-10  7:09                       ` Nick Piggin
2007-07-10 22:09                         ` Christoph Lameter
2007-07-10 23:12                           ` Matt Mackall
2007-07-10  8:32                       ` Matt Mackall
2007-07-10  9:01                         ` Håvard Skinnemoen
2007-07-10  9:11                           ` Nick Piggin
2007-07-10  9:21                             ` Håvard Skinnemoen
2007-07-11  1:37                         ` Christoph Lameter
2007-07-11  2:06                           ` Matt Mackall
2007-07-11 18:06                             ` Christoph Lameter
2007-07-11 18:25                               ` Pekka J Enberg
2007-07-11 18:33                                 ` Christoph Lameter
2007-07-11 18:36                                   ` Pekka J Enberg
2007-07-12  0:33                                 ` Nick Piggin
2007-07-09 23:09             ` Matt Mackall
2007-07-10  1:41           ` Nick Piggin
2007-07-10  1:51             ` Christoph Lameter
2007-07-10  1:58               ` Nick Piggin
2007-07-10  6:22                 ` Matt Mackall
2007-07-10  7:03                   ` Nick Piggin
2007-07-10  2:32               ` Matt Mackall
2007-07-09 21:57       ` Matt Mackall [this message]
2007-07-09 12:31     ` Matthieu CASTET
2007-07-09 16:00     ` Christoph Lameter
2007-07-09 20:52   ` Matt Mackall
2007-07-08  3:50 ` [patch 10/10] Remove slab in 2.6.24 Christoph Lameter
2007-07-08  4:37 ` [patch 00/10] [RFC] SLUB patches for more functionality, performance and maintenance David Miller
2007-07-09 15:45   ` Christoph Lameter
2007-07-09 19:43     ` David Miller
2007-07-09 21:21       ` Christoph Lameter
2007-07-08 11:20 ` Andi Kleen
2007-07-09 15:50   ` Christoph Lameter
2007-07-09 15:59     ` Martin Bligh
2007-07-09 18:11       ` Christoph Lameter
2007-07-09 21:00         ` Martin Bligh
2007-07-09 21:44           ` Mathieu Desnoyers
2007-07-09 21:55             ` Christoph Lameter
2007-07-09 22:58               ` Mathieu Desnoyers
2007-07-09 23:08                 ` Christoph Lameter
2007-07-10  5:16                   ` [PATCH] x86_64 - Use non locked version for local_cmpxchg() Mathieu Desnoyers
2007-07-10 20:46                     ` Christoph Lameter
2007-07-10  0:55                 ` [patch 00/10] [RFC] SLUB patches for more functionality, performance and maintenance Christoph Lameter
2007-07-10  8:27                   ` Mathieu Desnoyers
2007-07-10 18:38                     ` Christoph Lameter
2007-07-10 20:59                     ` Mathieu Desnoyers
2007-08-13 22:18                   ` Mathieu Desnoyers
2007-08-13 22:28                     ` Christoph Lameter

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