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From: Hyeonggon Yoo <42.hyeyoo@gmail.com>
To: cl@linux.com, penberg@kernel.org, rientjes@google.com,
	iamjoonsoo.kim@lge.com, vbabka@suse.cz
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Hyeonggon Yoo <42.hyeyoo@gmail.com>
Subject: [PATCH] mm: kmalloc_index: remove case when size is more than 32MB
Date: Sun,  9 May 2021 07:13:28 +0900	[thread overview]
Message-ID: <20210508221328.7338-1-42.hyeyoo@gmail.com> (raw)

the return value of kmalloc_index is used as index of kmalloc_caches,
which is defined as:
  struct kmem_cache *
  kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1]

and KMALLOC_SHIFT_HIGH is defined as:
  #define KMALLOC_SHIFT_HIGH    ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
                              (MAX_ORDER + PAGE_SHIFT - 1) : 25)

KMALLOC_SHIFT_HIGH is maximum 25 by its definition. thus index of
kmalloc_caches cannot be 26. so this case should be removed.

Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
---
 include/linux/slab.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 0c97d788762c..4694b1db4cb2 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -382,7 +382,6 @@ static __always_inline unsigned int kmalloc_index(size_t size)
 	if (size <=  8 * 1024 * 1024) return 23;
 	if (size <=  16 * 1024 * 1024) return 24;
 	if (size <=  32 * 1024 * 1024) return 25;
-	if (size <=  64 * 1024 * 1024) return 26;
 	BUG();
 
 	/* Will never be reached. Needed because the compiler may complain */
-- 
2.25.1



             reply	other threads:[~2021-05-08 22:13 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-08 22:13 Hyeonggon Yoo [this message]
2021-05-08 23:19 ` [PATCH] mm: kmalloc_index: remove case when size is more than 32MB Matthew Wilcox
2021-05-09  5:33   ` Hyeonggon Yoo
2021-05-10 10:09     ` Vlastimil Babka
2021-05-10 13:58       ` Hyeonggon Yoo
2021-05-10 14:04         ` Vlastimil Babka
2021-05-10 15:02           ` [PATCH v2] mm: kmalloc_index: make compiler break when size is not supported Hyeonggon Yoo
2021-05-10 15:15             ` Christoph Lameter
2021-05-10 15:21               ` Vlastimil Babka
2021-05-11  3:09               ` Hyeonggon Yoo
2021-05-10 15:19             ` Vlastimil Babka
2021-05-10 15:38               ` Hyeonggon Yoo
2021-05-11  8:36                 ` Vlastimil Babka
2021-05-11  8:37                   ` Vlastimil Babka
2021-05-11  9:14                     ` Hyeonggon Yoo
2021-05-11  2:59               ` [PATCH v3] mm: change run-time assertion in kmalloc_index() to compile-time Hyeonggon Yoo
2021-05-10 15:44             ` [PATCH v2] mm: kmalloc_index: make compiler break when size is not supported Matthew Wilcox
2021-05-11  3:03               ` Hyeonggon Yoo
2021-05-11  8:33                 ` Vlastimil Babka

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