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From: Tejun Heo <tj@kernel.org>
To: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux-foundation.org>,
	Pekka Enberg <penberg@cs.helsinki.fi>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Nick Piggin <npiggin@suse.de>
Subject: Re: [S+Q3 00/23] SLUB: The Unified slab allocator (V3)
Date: Tue, 17 Aug 2010 09:55:56 +0200	[thread overview]
Message-ID: <4C6A408C.6040203@kernel.org> (raw)
In-Reply-To: <alpine.DEB.2.00.1008151627450.27137@chino.kir.corp.google.com>

Hello,

On 08/17/2010 06:56 AM, David Rientjes wrote:
> I'm adding Tejun Heo to the cc because of another thing that may be 
> problematic: alloc_percpu() allocates GFP_KERNEL memory, so when we try to 
> allocate kmem_cache_cpu for a DMA cache we may be returning memory from a 
> node that doesn't include lowmem so there will be no affinity between the 
> struct and the slab.  I'm wondering if it would be better for the percpu 
> allocator to be extended for kzalloc_node(), or vmalloc_node(), when 
> allocating memory after the slab layer is up.

Hmmm... do you mean adding @gfp_mask to percpu allocation function?
I've been thinking about adding it for atomic allocations (Christoph,
do you still want it?).  I've been sort of against it because I
primarily don't really like atomic allocations (it often just pushes
error handling complexities elsewhere where it becomes more complex)
and it would also require making vmalloc code do atomic allocations.

Most of percpu use cases seem pretty happy with GFP_KERNEL allocation,
so I'm still quite reluctant to change that.  We can add a semi
internal interface w/ @gfp_mask but w/o GFP_ATOMIC support, which is a
bit ugly.  How important would this be?

Thanks.

-- 
tejun

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  reply	other threads:[~2010-08-17  7:59 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-04  2:45 [S+Q3 00/23] SLUB: The Unified slab allocator (V3) Christoph Lameter
2010-08-04  2:45 ` [S+Q3 01/23] percpu: make @dyn_size always mean min dyn_size in first chunk init functions Christoph Lameter
2010-08-04  2:45 ` [S+Q3 02/23] percpu: allow limited allocation before slab is online Christoph Lameter
2010-08-04  2:45 ` [S+Q3 03/23] slub: Use a constant for a unspecified node Christoph Lameter
2010-08-04  3:34   ` David Rientjes
2010-08-04 16:15     ` Christoph Lameter
2010-08-05  7:40       ` David Rientjes
2010-08-04  2:45 ` [S+Q3 04/23] SLUB: Constants need UL Christoph Lameter
2010-08-04  2:45 ` [S+Q3 05/23] Subjec Slub: Force no inlining of debug functions Christoph Lameter
2010-08-04  2:45 ` [S+Q3 06/23] slub: Check kasprintf results in kmem_cache_init() Christoph Lameter
2010-08-04  2:45 ` [S+Q3 07/23] slub: Use kmem_cache flags to detect if slab is in debugging mode Christoph Lameter
2010-08-04  2:45 ` [S+Q3 08/23] slub: remove dynamic dma slab allocation Christoph Lameter
2010-08-04  2:45 ` [S+Q3 09/23] slub: Remove static kmem_cache_cpu array for boot Christoph Lameter
2010-08-04  2:45 ` [S+Q3 10/23] slub: Allow removal of slab caches during boot V2 Christoph Lameter
2010-08-04  2:45 ` [S+Q3 11/23] slub: Dynamically size kmalloc cache allocations Christoph Lameter
2010-08-04  2:45 ` [S+Q3 12/23] slub: Extract hooks for memory checkers from hotpaths Christoph Lameter
2010-08-04  2:45 ` [S+Q3 13/23] slub: Move gfpflag masking out of the hotpath Christoph Lameter
2010-08-04  2:45 ` [S+Q3 14/23] slub: Add SLAB style per cpu queueing Christoph Lameter
2010-08-04  2:45 ` [S+Q3 15/23] slub: Allow resizing of per cpu queues Christoph Lameter
2010-08-04  2:45 ` [S+Q3 16/23] slub: Get rid of useless function count_free() Christoph Lameter
2010-08-04  2:45 ` [S+Q3 17/23] slub: Remove MAX_OBJS limitation Christoph Lameter
2010-08-04  2:45 ` [S+Q3 18/23] slub: Drop allocator announcement Christoph Lameter
2010-08-04  2:45 ` [S+Q3 19/23] slub: Object based NUMA policies Christoph Lameter
2010-08-04  2:45 ` [S+Q3 20/23] slub: Shared cache to exploit cross cpu caching abilities Christoph Lameter
2010-08-17  5:52   ` David Rientjes
2010-08-17 17:51     ` Christoph Lameter
2010-08-17 18:42       ` David Rientjes
2010-08-17 18:50         ` Christoph Lameter
2010-08-17 19:02           ` David Rientjes
2010-08-17 19:32             ` Christoph Lameter
2010-08-18 19:32               ` Christoph Lameter
2010-08-04  2:45 ` [S+Q3 21/23] slub: Support Alien Caches Christoph Lameter
2010-08-04  2:45 ` [S+Q3 22/23] slub: Cached object expiration Christoph Lameter
2010-08-04  2:45 ` [S+Q3 23/23] vmscan: Tie slub object expiration into page reclaim Christoph Lameter
2010-08-04  4:39 ` [S+Q3 00/23] SLUB: The Unified slab allocator (V3) David Rientjes
2010-08-04 16:17   ` Christoph Lameter
2010-08-05  8:38     ` David Rientjes
2010-08-05 17:33       ` Christoph Lameter
2010-08-17  4:56         ` David Rientjes
2010-08-17  7:55           ` Tejun Heo [this message]
2010-08-17 13:56             ` Christoph Lameter
2010-08-17 17:23           ` Christoph Lameter
2010-08-17 17:29             ` Christoph Lameter
2010-08-17 18:02             ` David Rientjes
2010-08-17 18:47               ` Christoph Lameter
2010-08-17 18:54                 ` David Rientjes
2010-08-17 19:34                   ` Christoph Lameter

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