From: Christoph Lameter <cl@linux.com>
To: Dave Hansen <dave@sr71.net>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kirill.shutemov@linux.intel.com, Andi Kleen <ak@linux.intel.com>
Subject: Re: [RFC][PATCH 1/3] mm: slab: create helpers for slab ->freelist pointer
Date: Thu, 12 Dec 2013 19:32:22 +0000 [thread overview]
Message-ID: <00000142e84bacf0-e6eeb332-e66b-48c6-95d8-d4a7cba0f24d-000000@email.amazonses.com> (raw)
In-Reply-To: <20131211224023.5F39AC88@viggo.jf.intel.com>
On Wed, 11 Dec 2013, Dave Hansen wrote:
>
> We have a need to move the ->freelist data around 'struct page'
> in order to keep a cmpxchg aligned. First step is to add an
> accessor function which we will hook in to in the next patch.
>
> I'm not super-happy with how this looks. It's a bit ugly, but it
> does work. I'm open to some better suggestions for how to do
> this.
I think the mapping field is not used by SLUB and its ok to use since SLAB
uses it for its memory pointer. Maybe you can use that to get the correct
alignment? Do an and of address used for the cmpxchg with 0xffff
.. ff0 to ensure proper aligment (the resulting address may overlap
the mapping field).
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next prev parent reply other threads:[~2013-12-12 19:32 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-11 22:40 [RFC][PATCH 0/3] re-shrink 'struct page' when SLUB is on Dave Hansen
2013-12-11 22:40 ` [RFC][PATCH 1/3] mm: slab: create helpers for slab ->freelist pointer Dave Hansen
2013-12-12 19:32 ` Christoph Lameter [this message]
2013-12-11 22:40 ` [RFC][PATCH 2/3] mm: slab: move around slab ->freelist for cmpxchg Dave Hansen
2013-12-12 17:46 ` Christoph Lameter
2013-12-12 19:39 ` Dave Hansen
2013-12-12 23:40 ` Andi Kleen
2013-12-11 22:40 ` [RFC][PATCH 3/3] mm: slabs: reset page at free Dave Hansen
2013-12-12 17:44 ` Christoph Lameter
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