From 9fe79ad1e43d236bbbb8edb3cf634356de714c79 Mon Sep 17 00:00:00 2001 From: KaiGai Kohei Date: Sat, 29 Sep 2007 02:20:55 +0900 Subject: SELinux: improve performance when AVC misses. * We add ebitmap_for_each_positive_bit() which enables to walk on any positive bit on the given ebitmap, to improve its performance using common bit-operations defined in linux/bitops.h. In the previous version, this logic was implemented using a combination of ebitmap_for_each_bit() and ebitmap_node_get_bit(), but is was worse in performance aspect. This logic is most frequestly used to compute a new AVC entry, so this patch can improve SELinux performance when AVC misses are happen. * struct ebitmap_node is redefined as an array of "unsigned long", to get suitable for using find_next_bit() which is fasted than iteration of shift and logical operation, and to maximize memory usage allocated from general purpose slab. * Any ebitmap_for_each_bit() are repleced by the new implementation in ss/service.c and ss/mls.c. Some of related implementation are changed, however, there is no incompatibility with the previous version. * The width of any new line are less or equal than 80-chars. The following benchmark shows the effect of this patch, when we access many files which have different security context one after another. The number is more than /selinux/avc/cache_threshold, so any access always causes AVC misses. selinux-2.6 selinux-2.6-ebitmap AVG: 22.763 [s] 8.750 [s] STD: 0.265 0.019 ------------------------------------------ 1st: 22.558 [s] 8.786 [s] 2nd: 22.458 [s] 8.750 [s] 3rd: 22.478 [s] 8.754 [s] 4th: 22.724 [s] 8.745 [s] 5th: 22.918 [s] 8.748 [s] 6th: 22.905 [s] 8.764 [s] 7th: 23.238 [s] 8.726 [s] 8th: 22.822 [s] 8.729 [s] Signed-off-by: KaiGai Kohei Acked-by: Stephen Smalley Signed-off-by: James Morris --- security/selinux/ss/services.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) (limited to 'security/selinux/ss/services.c') diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index 03140edf97a..d572dc908f3 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -353,12 +353,8 @@ static int context_struct_compute_av(struct context *scontext, avkey.specified = AVTAB_AV; sattr = &policydb.type_attr_map[scontext->type - 1]; tattr = &policydb.type_attr_map[tcontext->type - 1]; - ebitmap_for_each_bit(sattr, snode, i) { - if (!ebitmap_node_get_bit(snode, i)) - continue; - ebitmap_for_each_bit(tattr, tnode, j) { - if (!ebitmap_node_get_bit(tnode, j)) - continue; + ebitmap_for_each_positive_bit(sattr, snode, i) { + ebitmap_for_each_positive_bit(tattr, tnode, j) { avkey.source_type = i + 1; avkey.target_type = j + 1; for (node = avtab_search_node(&policydb.te_avtab, &avkey); @@ -1668,14 +1664,10 @@ int security_get_user_sids(u32 fromsid, goto out_unlock; } - ebitmap_for_each_bit(&user->roles, rnode, i) { - if (!ebitmap_node_get_bit(rnode, i)) - continue; + ebitmap_for_each_positive_bit(&user->roles, rnode, i) { role = policydb.role_val_to_struct[i]; usercon.role = i+1; - ebitmap_for_each_bit(&role->types, tnode, j) { - if (!ebitmap_node_get_bit(tnode, j)) - continue; + ebitmap_for_each_positive_bit(&role->types, tnode, j) { usercon.type = j+1; if (mls_setup_user_range(fromcon, user, &usercon)) -- cgit v1.2.3