From: David Rientjes <rientjes@google.com>
To: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>,
Andi Kleen <andi@firstfloor.org>,
tj@kernel.org, Metathronius Galabant <m.galabant@googlemail.com>,
Matt Mackall <mpm@selenic.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
Adrian Drzewiecki <z@drze.net>, Shaohua Li <shaohua.li@intel.com>,
Alex Shi <alex.shi@intel.com>,
linux-mm@kvack.org
Subject: Re: [rfc 01/18] slub: Get rid of the node field
Date: Sun, 20 Nov 2011 15:01:35 -0800 (PST) [thread overview]
Message-ID: <alpine.DEB.2.00.1111201458520.30815@chino.kir.corp.google.com> (raw)
In-Reply-To: <20111111200725.634567005@linux.com>
On Fri, 11 Nov 2011, Christoph Lameter wrote:
> The node field is always page_to_nid(c->page). So its rather easy to
> replace. Note that there will be additional overhead in various hot paths
> due to the need to mask a set of bits in page->flags and shift the
> result.
>
This certainly does add overhead to the fastpath just by checking
node_match() if we're doing kmalloc_node(), and that overhead might be
higher than you expect if NODE_NOT_IN_PAGE_FLAGS. Storing the node in
kmem_cache_cpu was always viewed as an optimization, not sure why you'd
want to get rid of it? The changelog at least doesn't mention any
motivation. Do we need to shrink that struct for something else later or
something?
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next prev parent reply other threads:[~2011-11-20 23:01 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-11 20:07 [rfc 00/18] slub: irqless/lockless slow allocation paths Christoph Lameter
2011-11-11 20:07 ` [rfc 01/18] slub: Get rid of the node field Christoph Lameter
2011-11-14 21:42 ` Pekka Enberg
2011-11-15 16:07 ` Christoph Lameter
2011-11-20 23:01 ` David Rientjes [this message]
2011-11-21 17:17 ` Christoph Lameter
2011-11-11 20:07 ` [rfc 02/18] slub: Separate out kmem_cache_cpu processing from deactivate_slab Christoph Lameter
2011-11-20 23:10 ` David Rientjes
2011-11-11 20:07 ` [rfc 03/18] slub: Extract get_freelist from __slab_alloc Christoph Lameter
2011-11-14 21:43 ` Pekka Enberg
2011-11-15 16:08 ` Christoph Lameter
2011-12-13 20:31 ` Pekka Enberg
2011-11-20 23:18 ` David Rientjes
2011-11-11 20:07 ` [rfc 04/18] slub: Use freelist instead of "object" in __slab_alloc Christoph Lameter
2011-11-14 21:44 ` Pekka Enberg
2011-11-20 23:22 ` David Rientjes
2011-11-11 20:07 ` [rfc 05/18] slub: Simplify control flow in __slab_alloc() Christoph Lameter
2011-11-14 21:45 ` Pekka Enberg
2011-11-20 23:24 ` David Rientjes
2011-11-11 20:07 ` [rfc 06/18] slub: Use page variable instead of c->page Christoph Lameter
2011-11-14 21:46 ` Pekka Enberg
2011-11-20 23:27 ` David Rientjes
2011-11-11 20:07 ` [rfc 07/18] slub: pass page to node_match() instead of kmem_cache_cpu structure Christoph Lameter
2011-11-20 23:28 ` David Rientjes
2011-11-11 20:07 ` [rfc 08/18] slub: enable use of deactivate_slab with interrupts on Christoph Lameter
2011-11-11 20:07 ` [rfc 09/18] slub: Run deactivate_slab with interrupts enabled Christoph Lameter
2011-11-11 20:07 ` [rfc 10/18] slub: Enable use of get_partial " Christoph Lameter
2011-11-11 20:07 ` [rfc 11/18] slub: Acquire_slab() avoid loop Christoph Lameter
2011-11-11 20:07 ` [rfc 12/18] slub: Remove kmem_cache_cpu dependency from acquire slab Christoph Lameter
2011-11-11 20:07 ` [rfc 13/18] slub: Add functions to manage per cpu freelists Christoph Lameter
2011-11-11 20:07 ` [rfc 14/18] slub: Decomplicate the get_pointer_safe call and fixup statistics Christoph Lameter
2011-11-11 20:07 ` [rfc 15/18] slub: new_slab_objects() can also get objects from partial list Christoph Lameter
2011-11-11 20:07 ` [rfc 16/18] slub: Drop page field from kmem_cache_cpu Christoph Lameter
2011-11-11 20:07 ` [rfc 17/18] slub: Move __slab_free() into slab_free() Christoph Lameter
2011-11-11 20:07 ` [rfc 18/18] slub: Move __slab_alloc() into slab_alloc() Christoph Lameter
2011-11-16 17:39 ` [rfc 00/18] slub: irqless/lockless slow allocation paths Eric Dumazet
2011-11-16 17:45 ` Eric Dumazet
2011-11-20 23:32 ` David Rientjes
2011-11-20 23:30 ` David Rientjes
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