mm/slab.c: only set __GFP_RECLAIMABLE once

SLAB_RECLAIM_ACCOUNT is a permanent attribute of a slab cache.  Set
__GFP_RECLAIMABLE as part of its ->allocflags rather than check the
cachep flag on every page allocation.

Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1710171527560.140898@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/slab.c

@@ -1410,8 +1410,6 @@ static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
 	int nr_pages;
 
 	flags |= cachep->allocflags;
-	if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
-		flags |= __GFP_RECLAIMABLE;
 
 	page = __alloc_pages_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
 	if (!page) {
@@ -2144,6 +2142,8 @@ done:
 	cachep->allocflags = __GFP_COMP;
 	if (flags & SLAB_CACHE_DMA)
 		cachep->allocflags |= GFP_DMA;
+	if (flags & SLAB_RECLAIM_ACCOUNT)
+		cachep->allocflags |= __GFP_RECLAIMABLE;
 	cachep->size = size;
 	cachep->reciprocal_buffer_size = reciprocal_value(size);