path: root/security/selinux/ss/ebitmap.h
diff options
authorStephen Smalley <sds@tycho.nsa.gov>2005-09-03 15:55:16 -0700
committerLinus Torvalds <torvalds@evo.osdl.org>2005-09-05 00:05:50 -0700
commit782ebb992ec20b5afdd5786ee8c2f1b58b631f24 (patch)
treeadf0af44fa591d803ec6b9ab7541ff3e5745dd93 /security/selinux/ss/ebitmap.h
parent720d6c29e146e96cca858057469951e91e0e6850 (diff)
[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>
Diffstat (limited to 'security/selinux/ss/ebitmap.h')
1 files changed, 30 insertions, 0 deletions
diff --git a/security/selinux/ss/ebitmap.h b/security/selinux/ss/ebitmap.h
index 471370233fd..8bf41055a6c 100644
--- a/security/selinux/ss/ebitmap.h
+++ b/security/selinux/ss/ebitmap.h
@@ -32,11 +32,41 @@ struct ebitmap {
#define ebitmap_length(e) ((e)->highbit)
#define ebitmap_startbit(e) ((e)->node ? (e)->node->startbit : 0)
+static inline unsigned int ebitmap_start(struct ebitmap *e,
+ struct ebitmap_node **n)
+ *n = e->node;
+ return ebitmap_startbit(e);
static inline void ebitmap_init(struct ebitmap *e)
memset(e, 0, sizeof(*e));
+static inline unsigned int ebitmap_next(struct ebitmap_node **n,
+ unsigned int bit)
+ if ((bit == ((*n)->startbit + MAPSIZE - 1)) &&
+ (*n)->next) {
+ *n = (*n)->next;
+ return (*n)->startbit;
+ }
+ return (bit+1);
+static inline int ebitmap_node_get_bit(struct ebitmap_node * n,
+ unsigned int bit)
+ if (n->map & (MAPBIT << (bit - n->startbit)))
+ return 1;
+ return 0;
+#define ebitmap_for_each_bit(e, n, bit) \
+ for (bit = ebitmap_start(e, &n); bit < ebitmap_length(e); bit = ebitmap_next(&n, bit)) \
int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2);
int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src);
int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2);