From: Joonsoo Kim <[email protected]> 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 <[email protected]> Cc: Christoph Lameter <[email protected]> Cc: Pekka Enberg <[email protected]> Cc: David Rientjes <[email protected]> Cc: Joonsoo Kim <[email protected]> Cc: Jesper Dangaard Brouer <[email protected]> Signed-off-by: Andrew Morton <[email protected]> --- mm/slab.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index 9b56685..21aad9d 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -2206,10 +2206,17 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags) */ if (debug_pagealloc_enabled() && (flags & SLAB_POISON) && !slab_early_init && size >= kmalloc_size(INDEX_NODE) && - size >= 256 && cachep->object_size > cache_line_size() && - size < PAGE_SIZE) { - cachep->obj_offset += PAGE_SIZE - size; - size = PAGE_SIZE; + size >= 256 && cachep->object_size > cache_line_size()) { + if (size < PAGE_SIZE || size % PAGE_SIZE == 0) { + size_t tmp_size = ALIGN(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 -- 1.9.1
