From: Andi Kleen <andi@firstfloor.org>
To: David Chinner <dgc@sgi.com>
Cc: Andi Kleen <andi@firstfloor.org>,
Lachlan McIlroy <lachlan@sgi.com>, xfs-dev <xfs-dev@sgi.com>,
xfs-oss <xfs@oss.sgi.com>
Subject: Re: [Patch] Cacheline align xlog_t
Date: Thu, 3 Apr 2008 08:46:08 +0200 [thread overview]
Message-ID: <20080403064608.GS29105@one.firstfloor.org> (raw)
In-Reply-To: <20080402222347.GK103491721@sgi.com>
On Thu, Apr 03, 2008 at 08:23:47AM +1000, David Chinner wrote:
> > For the dynamic allocation you would rather need to make sure it
> > starts at a cache line boundary explicitely because the allocator doesn't
> > know the alignment of the target type, otherwise your careful
> > padding might be useless.
>
> Yup. Is there an allocator function gives us cacheline aligned
> allocation
__get_free_pages() @) [ok not serious]
> (apart from a slab initialised with SLAB_HWCACHE_ALIGN)?
That too yes.
> There isn't one, right?
You can always align yourself with kmalloc (or any other arbitary
size allocator) with the standard technique:
get L1_CACHE_BYTES-1 or possibly better cache_line_size() - 1 bytes
more and then align the pointer manually with ALIGN. Only tricky part
is that you have to undo the alignment before freeing.
-Andi
next prev parent reply other threads:[~2008-04-03 6:42 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-01 23:15 [Patch] Cacheline align xlog_t David Chinner
2008-04-02 6:35 ` Lachlan McIlroy
2008-04-02 5:44 ` David Chinner
2008-04-02 8:28 ` Andi Kleen
2008-04-02 22:23 ` David Chinner
2008-04-03 6:46 ` Andi Kleen [this message]
2008-04-04 1:02 ` Timothy Shimmin
2008-04-04 1:18 ` David Chinner
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