mm/slab: do not change cache size if debug pagealloc isn't possible

We can fail to setup off slab in some conditions.  Even in this case,
debug pagealloc increases cache size to PAGE_SIZE in advance and it is
waste because debug pagealloc cannot work for it when it isn't the off
slab.  To improve this situation, this patch checks first that this
cache with increased size is suitable for off slab.  It actually
increases cache size when it is suitable for off-slab, so possible waste
is removed.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Joonsoo Kim 2016-03-15 14:54:38 -07:00 committed by Linus Torvalds
parent 158e319bba
commit f3a3c320d5

View File

@ -2206,10 +2206,17 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
*/ */
if (debug_pagealloc_enabled() && (flags & SLAB_POISON) && if (debug_pagealloc_enabled() && (flags & SLAB_POISON) &&
!slab_early_init && size >= kmalloc_size(INDEX_NODE) && !slab_early_init && size >= kmalloc_size(INDEX_NODE) &&
size >= 256 && cachep->object_size > cache_line_size() && size >= 256 && cachep->object_size > cache_line_size()) {
size < PAGE_SIZE) { if (size < PAGE_SIZE || size % PAGE_SIZE == 0) {
cachep->obj_offset += PAGE_SIZE - size; size_t tmp_size = ALIGN(size, PAGE_SIZE);
size = PAGE_SIZE;
if (set_off_slab_cache(cachep, tmp_size, flags)) {
flags |= CFLGS_OFF_SLAB;
cachep->obj_offset += tmp_size - size;
size = tmp_size;
goto done;
}
}
} }
#endif #endif