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
Subject: Re: [S+Q Cleanup 3/6] slub: Remove static kmem_cache_cpu array for boot
Date: Wed, 18 Aug 2010 08:09:19 +0200 [thread overview]
Message-ID: <4C6B790F.5030405@kernel.org> (raw)
In-Reply-To: <alpine.DEB.2.00.1008171638160.31928@chino.kir.corp.google.com>
On 08/18/2010 01:58 AM, David Rientjes wrote:
> On Tue, 17 Aug 2010, Christoph Lameter wrote:
>
>> Index: linux-2.6/mm/slub.c
>> ===================================================================
>> --- linux-2.6.orig/mm/slub.c 2010-08-13 10:32:45.000000000 -0500
>> +++ linux-2.6/mm/slub.c 2010-08-13 10:32:50.000000000 -0500
>> @@ -2062,23 +2062,14 @@ init_kmem_cache_node(struct kmem_cache_n
>> #endif
>> }
>>
>> -static DEFINE_PER_CPU(struct kmem_cache_cpu, kmalloc_percpu[KMALLOC_CACHES]);
>> -
>> static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
>> {
>> - if (s < kmalloc_caches + KMALLOC_CACHES && s >= kmalloc_caches)
>> - /*
>> - * Boot time creation of the kmalloc array. Use static per cpu data
>> - * since the per cpu allocator is not available yet.
>> - */
>> - s->cpu_slab = kmalloc_percpu + (s - kmalloc_caches);
>> - else
>> - s->cpu_slab = alloc_percpu(struct kmem_cache_cpu);
>> + BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
>> + SLUB_PAGE_SHIFT * sizeof(struct kmem_cache));
>
> This fails with CONFIG_NODES_SHIFT=10 on x86_64, which means it will fail
> the ia64 defconfig as well. struct kmem_cache stores nodemask pointers up
> to MAX_NUMNODES, which makes the conditional fail.
>
> struct kmem_cache is 8376 bytes with that config (and CONFIG_SLUB_DEBUG),
> so it looks like PERCPU_DYNAMIC_EARLY_SIZE will need to be at least 117264
> for this not to fail (four orders larger than it currently is, or
> 12 << 14). Tejun?
Heh, if it gets that high, probably the right thing to do is to define
SLUB_PERCPU_EARLY_SIZE and define PERCPU_DYNAMIC_EARLY_SIZE in terms
of it.
Thaks.
--
tejun
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next prev parent reply other threads:[~2010-08-18 6:09 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-17 21:11 [S+Q Cleanup 0/6] SLUB: Cleanups Christoph Lameter
2010-08-17 21:11 ` [S+Q Cleanup 1/6] Slub: Force no inlining of debug functions Christoph Lameter
2010-08-17 23:13 ` David Rientjes
2010-08-17 21:11 ` [S+Q Cleanup 2/6] slub: remove dynamic dma slab allocation Christoph Lameter
2010-08-17 23:35 ` David Rientjes
2010-08-18 14:46 ` Christoph Lameter
2010-08-17 21:11 ` [S+Q Cleanup 3/6] slub: Remove static kmem_cache_cpu array for boot Christoph Lameter
2010-08-17 23:58 ` David Rientjes
2010-08-18 6:09 ` Tejun Heo [this message]
2010-08-18 14:54 ` Christoph Lameter
2010-08-17 21:11 ` [S+Q Cleanup 4/6] slub: Dynamically size kmalloc cache allocations Christoph Lameter
2010-08-17 21:11 ` [S+Q Cleanup 5/6] slub: Extract hooks for memory checkers from hotpaths Christoph Lameter
2010-08-18 0:28 ` David Rientjes
2010-08-18 14:58 ` Christoph Lameter
2010-08-17 21:11 ` [S+Q Cleanup 6/6] slub: Move gfpflag masking out of the hotpath Christoph Lameter
2010-08-18 0:35 ` David Rientjes
2010-08-18 15:46 ` Christoph Lameter
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