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authorWaiman Long <Waiman.Long@hp.com>2013-07-23 17:38:41 -0400
committerEric Paris <eparis@redhat.com>2013-07-25 13:02:31 -0400
commita767f680e34bf14a36fefbbb6d85783eef99fd57 (patch)
tree283889d4951dcb42a4de713e144f2d556552c27c /security/selinux/ss
parentfee7114298cf54bbd221cdb2ab49738be8b94f4c (diff)
SELinux: Increase ebitmap_node size for 64-bit configuration
Currently, the ebitmap_node structure has a fixed size of 32 bytes. On a 32-bit system, the overhead is 8 bytes, leaving 24 bytes for being used as bitmaps. The overhead ratio is 1/4. On a 64-bit system, the overhead is 16 bytes. Therefore, only 16 bytes are left for bitmap purpose and the overhead ratio is 1/2. With a 3.8.2 kernel, a boot-up operation will cause the ebitmap_get_bit() function to be called about 9 million times. The average number of ebitmap_node traversal is about 3.7. This patch increases the size of the ebitmap_node structure to 64 bytes for 64-bit system to keep the overhead ratio at 1/4. This may also improve performance a little bit by making node to node traversal less frequent (< 2) as more bits are available in each node. Signed-off-by: Waiman Long <Waiman.Long@hp.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <pmoore@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Diffstat (limited to 'security/selinux/ss')
-rw-r--r--security/selinux/ss/ebitmap.h8
1 files changed, 7 insertions, 1 deletions
diff --git a/security/selinux/ss/ebitmap.h b/security/selinux/ss/ebitmap.h
index e7eb3a9c5ab7..712c8a7b8e8b 100644
--- a/security/selinux/ss/ebitmap.h
+++ b/security/selinux/ss/ebitmap.h
@@ -16,7 +16,13 @@
#include <net/netlabel.h>
-#define EBITMAP_UNIT_NUMS ((32 - sizeof(void *) - sizeof(u32)) \
+#ifdef CONFIG_64BIT
+#define EBITMAP_NODE_SIZE 64
+#else
+#define EBITMAP_NODE_SIZE 32
+#endif
+
+#define EBITMAP_UNIT_NUMS ((EBITMAP_NODE_SIZE-sizeof(void *)-sizeof(u32))\
/ sizeof(unsigned long))
#define EBITMAP_UNIT_SIZE BITS_PER_LONG
#define EBITMAP_SIZE (EBITMAP_UNIT_NUMS * EBITMAP_UNIT_SIZE)