linux-kernel - [PATCH v2 04/17] mm/slab: activate debug_pagealloc in SLAB when it is actually enabled

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Date:	Fri, 26 Feb 2016 15:01:11 +0900
From:	js1304@...il.com
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Christoph Lameter <cl@...ux.com>,
	Pekka Enberg <penberg@...nel.org>,
	David Rientjes <rientjes@...gle.com>,
	Jesper Dangaard Brouer <brouer@...hat.com>,
	Vlastimil Babka <vbabka@...e.cz>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, Joonsoo Kim <iamjoonsoo.kim@....com>
Subject: [PATCH v2 04/17] mm/slab: activate debug_pagealloc in SLAB when it is actually enabled

From: Joonsoo Kim <iamjoonsoo.kim@....com>

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@....com>
Cc: Christoph Lameter <cl@...ux.com>
Cc: Pekka Enberg <penberg@...nel.org>
Cc: David Rientjes <rientjes@...gle.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@....com>
Cc: Jesper Dangaard Brouer <brouer@...hat.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
---
 mm/slab.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 14c3f9c..4807cf4 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1838,7 +1838,8 @@ static void slab_destroy_debugcheck(struct kmem_cache *cachep,
 
 		if (cachep->flags & SLAB_POISON) {
 #ifdef CONFIG_DEBUG_PAGEALLOC
-			if (cachep->size % PAGE_SIZE == 0 &&
+			if (debug_pagealloc_enabled() &&
+				cachep->size % PAGE_SIZE == 0 &&
 					OFF_SLAB(cachep))
 				kernel_map_pages(virt_to_page(objp),
 					cachep->size / PAGE_SIZE, 1);
@@ -2176,7 +2177,8 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
 	 * to check size >= 256. It guarantees that all necessary small
 	 * sized slab is initialized in current slab initialization sequence.
 	 */
-	if (!slab_early_init && size >= kmalloc_size(INDEX_NODE) &&
+	if (debug_pagealloc_enabled() &&
+		!slab_early_init && size >= kmalloc_size(INDEX_NODE) &&
 		size >= 256 && cachep->object_size > cache_line_size() &&
 		ALIGN(size, cachep->align) < PAGE_SIZE) {
 		cachep->obj_offset += PAGE_SIZE - ALIGN(size, cachep->align);
@@ -2232,7 +2234,8 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
 		 * poisoning, then it's going to smash the contents of
 		 * the redzone and userword anyhow, so switch them off.
 		 */
-		if (size % PAGE_SIZE == 0 && flags & SLAB_POISON)
+		if (debug_pagealloc_enabled() &&
+			size % PAGE_SIZE == 0 && flags & SLAB_POISON)
 			flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
 #endif
 	}
@@ -2716,7 +2719,8 @@ static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
 	set_obj_status(page, objnr, OBJECT_FREE);
 	if (cachep->flags & SLAB_POISON) {
 #ifdef CONFIG_DEBUG_PAGEALLOC
-		if ((cachep->size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) {
+		if (debug_pagealloc_enabled() &&
+			(cachep->size % PAGE_SIZE) == 0 && OFF_SLAB(cachep)) {
 			store_stackinfo(cachep, objp, caller);
 			kernel_map_pages(virt_to_page(objp),
 					 cachep->size / PAGE_SIZE, 0);
@@ -2861,7 +2865,8 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
 		return objp;
 	if (cachep->flags & SLAB_POISON) {
 #ifdef CONFIG_DEBUG_PAGEALLOC
-		if ((cachep->size % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
+		if (debug_pagealloc_enabled() &&
+			(cachep->size % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
 			kernel_map_pages(virt_to_page(objp),
 					 cachep->size / PAGE_SIZE, 1);
 		else
-- 
1.9.1