linux-kernel - [PATCH v2 2/5] mm/slub: query dynamic DEBUG

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Date:	Thu, 11 Feb 2016 13:04:58 +0900
From:	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 v2 2/5] mm/slub: query dynamic DEBUG_PAGEALLOC setting

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

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

v2: clean up code, per Christian.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@....com>
---
 mm/slub.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 606488b..a1874c2 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -250,11 +250,10 @@ static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
 {
 	void *p;
 
-#ifdef CONFIG_DEBUG_PAGEALLOC
+	if (!debug_pagealloc_enabled())
+		return get_freepointer(s, object);
+
 	probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
-#else
-	p = get_freepointer(s, object);
-#endif
 	return p;
 }
 
-- 
1.9.1