linux/security
Waiman Long a767f680e3 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>
2013-07-25 13:02:31 -04:00
..
apparmor new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
integrity ima: eliminate passing d_name.name to process_measurement() 2013-04-17 17:20:57 -07:00
keys aio: don't include aio.h in sched.h 2013-05-07 20:16:25 -07:00
selinux SELinux: Increase ebitmap_node size for 64-bit configuration 2013-07-25 13:02:31 -04:00
smack Smack: include magic.h in smackfs.c 2013-04-03 13:13:51 +11:00
tomoyo Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
yama yama: Better permission check for ptraceme 2013-03-26 13:17:58 -07:00
capability.c lsm: split the xfrm_state_alloc_security() hook implementation 2013-07-25 13:01:25 -04:00
commoncap.c kill f_vfsmnt 2013-02-26 02:46:10 -05:00
device_cgroup.c devcg: remove parent_cgroup. 2013-04-18 11:34:35 -07:00
inode.c securityfs: fix object creation races 2012-01-10 10:20:35 -05:00
Kconfig KEYS: Move the key config into security/keys/Kconfig 2012-05-11 10:56:56 +01:00
lsm_audit.c LSM: BUILD_BUG_ON if the common_audit_data union ever grows 2012-04-09 12:23:03 -04:00
Makefile security: Yama LSM 2012-02-10 09:18:52 +11:00
min_addr.c mmap_min_addr check CAP_SYS_RAWIO only for write 2010-04-23 08:56:31 +10:00
security.c lsm: split the xfrm_state_alloc_security() hook implementation 2013-07-25 13:01:25 -04:00