slub: Determine gfpflags once and not every time a slab is allocated

Currently we determine the gfp flags to pass to the page allocator
each time a slab is being allocated.

Determine the bits to be set at the time the slab is created. Store
in a new allocflags field and add the flags in allocate_slab().

Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Christoph Lameter <clameter@sgi.com>

2 files changed, 12 insertions, 8 deletions

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index a849c472b845..98be113cf935 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -71,6 +71,7 @@ struct kmem_cache {
 
         /* Allocation and freeing of slabs */
         int objects;            /* Number of objects in slab */
+        gfp_t allocflags;       /* gfp flags to use on each alloc */
         int refcount;           /* Refcount for slab cache destroy */
         void (*ctor)(struct kmem_cache *, void *);
         int inuse;              /* Offset to metadata */
diff --git a/mm/slub.c b/mm/slub.c
index 1af7f2f19420..ccfd41141b6b 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1078,14 +1078,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
         struct page *page;
         int pages = 1 << s->order;
 
-        if (s->order)
-                flags |= __GFP_COMP;
-
-        if (s->flags & SLAB_CACHE_DMA)
-                flags |= SLUB_DMA;
-
-        if (s->flags & SLAB_RECLAIM_ACCOUNT)
-                flags |= __GFP_RECLAIMABLE;
+        flags |= s->allocflags;
 
         if (node == -1)
                 page = alloc_pages(flags, s->order);
@@ -2333,6 +2326,16 @@ static int calculate_sizes(struct kmem_cache *s)
         if (s->order < 0)
                 return 0;
 
+        s->allocflags = 0;
+        if (s->order)
+                s->allocflags |= __GFP_COMP;
+
+        if (s->flags & SLAB_CACHE_DMA)
+                s->allocflags |= SLUB_DMA;
+
+        if (s->flags & SLAB_RECLAIM_ACCOUNT)
+                s->allocflags |= __GFP_RECLAIMABLE;
+
         /*
          * Determine the number of objects per slab
          */