[PATCH] selinux: Reduce memory use by avtab
This patch improves memory use by SELinux by both reducing the avtab node
size and reducing the number of avtab nodes. The memory savings are
substantial, e.g. on a 64-bit system after boot, James Morris reported the
following data for the targeted and strict policies:
#objs objsize kernmem
Targeted:
Before: 237888 40 9.1MB
After: 19968 24 468KB
Strict:
Before: 571680 40 21.81MB
After: 221052 24 5.06MB
The improvement in memory use comes at a cost in the speed of security
server computations of access vectors, but these computations are only
required on AVC cache misses, and performance measurements by James Morris
using a number of benchmarks have shown that the change does not cause any
significant degradation.
Note that a rebuilt policy via an updated policy toolchain
(libsepol/checkpolicy) is required in order to gain the full benefits of
this patch, although some memory savings benefits are immediately applied
even to older policies (in particular, the reduction in avtab node size).
Sources for the updated toolchain are presently available from the
sourceforge CVS tree (http://sourceforge.net/cvs/?group_id=21266), and
tarballs are available from http://www.flux.utah.edu/~sds.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index 71c0a19..5f016c9 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -23,10 +23,11 @@
#define POLICYDB_VERSION_NLCLASS 18
#define POLICYDB_VERSION_VALIDATETRANS 19
#define POLICYDB_VERSION_MLS 19
+#define POLICYDB_VERSION_AVTAB 20
/* Range of policy versions we understand*/
#define POLICYDB_VERSION_MIN POLICYDB_VERSION_BASE
-#define POLICYDB_VERSION_MAX POLICYDB_VERSION_MLS
+#define POLICYDB_VERSION_MAX POLICYDB_VERSION_AVTAB
#ifdef CONFIG_SECURITY_SELINUX_BOOTPARAM
extern int selinux_enabled;