From: Christoph Lameter <clameter@sgi.com>
To: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Nick Piggin <npiggin@suse.de>,
netdev@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
yanmin_zhang@linux.intel.com, David Miller <davem@davemloft.net>,
Eric Dumazet <dada1@cosmosbay.com>
Subject: Re: [rfc][patch 1/3] slub: fix small HWCACHE_ALIGN alignment
Date: Mon, 3 Mar 2008 13:32:54 -0800 (PST) [thread overview]
Message-ID: <Pine.LNX.4.64.0803031331340.4375@schroedinger.engr.sgi.com> (raw)
In-Reply-To: <84144f020803031330i2c0ea1f6kc5b02c8b26145797@mail.gmail.com>
On Mon, 3 Mar 2008, Pekka Enberg wrote:
> Well, not my definition either but SLAB has guaranteed that for small
> objects in the past, so I think Nick has a point here. However, with
> all this back and forth, I've lost track why this matters. I suppose
> it causes regression on some workload?
Well the guarantee can only be exploited if you would check the cacheline
sizes and the object size from the code that creates the slab cache.
Basically you would have to guestimate what the slab allocator is doing.
So the guarantee is basically meaningless. If the object is larger than a
cacheline then this will never work.
next prev parent reply other threads:[~2008-03-03 21:33 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-03 9:34 Nick Piggin
2008-03-03 9:35 ` [rfc][patch 2/3] slab: introduce SMP alignment Nick Piggin
2008-03-03 19:06 ` Christoph Lameter
2008-03-03 20:03 ` Nick Piggin
2008-03-03 20:09 ` Christoph Lameter
2008-03-03 20:12 ` Nick Piggin
2008-03-03 20:17 ` Christoph Lameter
2008-03-03 20:24 ` Nick Piggin
2008-03-03 20:41 ` Pekka Enberg
2008-03-03 21:23 ` Christoph Lameter
2008-03-03 21:31 ` Christoph Lameter
2008-03-05 0:16 ` Nick Piggin
2008-03-07 4:37 ` Nick Piggin
2008-03-07 5:11 ` Christoph Lameter
2008-03-07 5:19 ` Nick Piggin
2008-03-07 5:26 ` Christoph Lameter
2008-03-07 5:37 ` Nick Piggin
2008-03-11 7:13 ` Nick Piggin
2008-03-12 6:21 ` Christoph Lameter
2008-03-03 9:36 ` [rfc][patch 3/3] use SLAB_ALIGN_SMP Nick Piggin
2008-03-03 9:53 ` Eric Dumazet
2008-03-03 12:41 ` Nick Piggin
2008-03-03 13:00 ` Eric Dumazet
2008-03-03 13:46 ` Nick Piggin
2008-03-03 13:53 ` Pekka Enberg
2008-03-03 14:15 ` Eric Dumazet
2008-03-03 19:10 ` Christoph Lameter
2008-03-03 19:09 ` Christoph Lameter
2008-03-03 20:10 ` Nick Piggin
2008-03-03 20:12 ` Christoph Lameter
2008-03-03 20:18 ` Nick Piggin
2008-03-03 21:14 ` Christoph Lameter
2008-03-03 9:44 ` [rfc][patch 1/3] slub: fix small HWCACHE_ALIGN alignment Pekka Enberg
2008-03-03 12:28 ` Nick Piggin
2008-03-03 19:08 ` Christoph Lameter
2008-03-03 20:06 ` Nick Piggin
2008-03-03 20:10 ` Christoph Lameter
2008-03-03 20:17 ` Nick Piggin
2008-03-03 21:16 ` Christoph Lameter
2008-03-03 21:30 ` Pekka Enberg
2008-03-03 21:32 ` Christoph Lameter [this message]
2008-03-03 21:35 ` Pekka Enberg
2008-03-05 0:28 ` Nick Piggin
2008-03-05 20:56 ` Christoph Lameter
2008-03-06 2:49 ` Nick Piggin
2008-03-06 22:53 ` Christoph Lameter
2008-03-07 2:04 ` Nick Piggin
2008-03-07 2:20 ` Christoph Lameter
2008-03-07 2:25 ` Nick Piggin
2008-03-07 2:27 ` Christoph Lameter
2008-03-07 2:33 ` Nick Piggin
2008-03-07 2:33 ` Christoph Lameter
2008-03-07 5:23 ` Nick Piggin
2008-03-05 0:08 ` Nick Piggin
2008-03-05 0:06 ` Nick Piggin
2008-03-05 0:10 ` David Miller
2008-03-05 21:06 ` Christoph Lameter
2008-03-06 2:57 ` Nick Piggin
2008-03-06 22:56 ` Christoph Lameter
2008-03-07 2:23 ` Nick Piggin
2008-03-07 2:26 ` Christoph Lameter
2008-03-07 2:32 ` Nick Piggin
2008-03-07 2:54 ` Christoph Lameter
2008-03-07 3:10 ` Nick Piggin
2008-03-07 3:18 ` Christoph Lameter
2008-03-07 3:22 ` Nick Piggin
2008-03-07 3:58 ` Christoph Lameter
2008-03-07 4:05 ` Nick Piggin
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