linux-kernel - [PATCH 2/5] mm/slub: query dynamic DEBUG

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Date:	Thu,  4 Feb 2016 14:56:23 +0900
From:	Joonsoo Kim <js1304@...il.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	David Rientjes <rientjes@...gle.com>,
	Christian Borntraeger <borntraeger@...ibm.com>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Takashi Iwai <tiwai@...e.com>,
	Chris Metcalf <cmetcalf@...hip.com>,
	Christoph Lameter <cl@...ux.com>, linux-api@...r.kernel.org,
	Joonsoo Kim <iamjoonsoo.kim@....com>
Subject: [PATCH 2/5] mm/slub: query dynamic DEBUG_PAGEALLOC setting

We can disable debug_pagealloc processing even if the code is complied
with CONFIG_DEBUG_PAGEALLOC. This patch changes the code to query
whether it is enabled or not in runtime.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@....com>
---
 mm/slub.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 7d4da68..7b5a965 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -256,11 +256,12 @@ static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
 {
 	void *p;
 
-#ifdef CONFIG_DEBUG_PAGEALLOC
-	probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
-#else
-	p = get_freepointer(s, object);
-#endif
+	if (debug_pagealloc_enabled()) {
+		probe_kernel_read(&p,
+			(void **)(object + s->offset), sizeof(p));
+	} else
+		p = get_freepointer(s, object);
+
 	return p;
 }
 
-- 
1.9.1