From: Ingo Molnar <mingo@elte.hu>
To: Christoph Lameter <cl@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
michal.simek@petalogix.com, linux-next@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>,
Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: problems in linux-next (Was: Re: linux-next: Tree for December 1)
Date: Tue, 1 Dec 2009 17:01:19 +0100 [thread overview]
Message-ID: <20091201160119.GA10826@elte.hu> (raw)
In-Reply-To: <alpine.DEB.2.00.0912010946340.8841@router.home>
* Christoph Lameter <cl@linux-foundation.org> wrote:
> On Tue, 1 Dec 2009, Tejun Heo wrote:
>
> > The problem is that on UP configurations. Percpu memory allocator
> > becomes a simple wrapper around kmalloc and there's no way to
> > specify larger alignment when requesting memory from kmalloc.
>
> There is usually no point in aligning in UP. Alignment is typically
> done for smp configurations to limit cache line bouncing and control
> cache line use/
There is a natural minimum alignment for UP and it's smaller than the
cache-line size: machine word size. All our allocators (except bootmem)
align to machine word so there's no need to specify this explicitly.
Larger alignment than that just wastes memory - which waste UP systems
can afford the least.
Ingo
next prev parent reply other threads:[~2009-12-01 16:01 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-01 8:03 linux-next: Tree for December 1 Stephen Rothwell
2009-12-01 8:42 ` Michal Simek
2009-12-01 10:03 ` problems in linux-next (Was: Re: linux-next: Tree for December 1) Stephen Rothwell
2009-12-01 14:50 ` Tejun Heo
2009-12-01 15:48 ` Christoph Lameter
2009-12-01 16:01 ` Ingo Molnar [this message]
2009-12-01 23:24 ` Tejun Heo
2009-12-02 7:55 ` Tejun Heo
2009-12-02 11:19 ` Michal Simek
2009-12-02 12:13 ` Tejun Heo
2009-12-02 14:55 ` Christoph Lameter
2009-12-02 22:16 ` Tejun Heo
2009-12-02 22:24 ` Christoph Lameter
2009-12-02 23:00 ` Tejun Heo
2009-12-02 5:40 ` Tejun Heo
2009-12-02 6:05 ` Stephen Rothwell
2009-12-01 10:29 ` linux-next: Tree for December 1 Mark Brown
2009-12-01 10:43 ` Takashi Iwai
2009-12-01 11:19 ` Stephen Rothwell
2009-12-01 10:57 ` Stephen Rothwell
2009-12-01 18:51 ` [PATCH -next] media/radio/miro: depends on SND Randy Dunlap
2009-12-01 18:52 ` [PATCH -next] kmsg_dump: fix build for CONFIG_PRINTK=n Randy Dunlap
2009-12-02 8:35 ` Simon Kagstrom
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