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Slub: UP bandaid

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Since the percpu allocator does not provide early allocation in UP mode (only
in SMP configurations) use __get_free_page() to improvise a compound page
allocation that can be later freed via kfree().

Compound pages will be released when the cpu caches are resized.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
This commit is contained in:
Christoph Lameter 2010-08-26 09:41:19 -05:00 committed by Pekka Enberg
parent a016471a16
commit db210e70e5
1 changed files with 16 additions and 0 deletions
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16
mm/slub.c
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@ -2103,8 +2103,24 @@ init_kmem_cache_node(struct kmem_cache_node *n, struct kmem_cache *s)
static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
{
#ifdef CONFIG_SMP
/*
* Will use reserve that does not require slab operation during
* early boot.
*/
BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
SLUB_PAGE_SHIFT * sizeof(struct kmem_cache_cpu));
#else
/*
* Special hack for UP mode. allocpercpu() falls back to kmalloc
* operations. So we cannot use that before the slab allocator is up
* Simply get the smallest possible compound page. The page will be
* released via kfree() when the cpu caches are resized later.
*/
if (slab_state < UP)
s->cpu_slab = (__percpu void *)kmalloc_large(PAGE_SIZE << 1, GFP_NOWAIT);
else
#endif
s->cpu_slab = alloc_percpu(struct kmem_cache_cpu);