From 044aea9b83614948c98564000db07d1d32b2d29b Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 19 May 2011 18:59:47 -0700 Subject: selinux: de-crapify avc cache stat code generation You can turn off the avc cache stats, but distributions seem to not do that (perhaps because several performance tuning how-to's talk about the avc cache statistics). Which is sad, because the code it generates is truly horrendous, with the statistics update being sandwitched between get_cpu/put_cpu which in turn causes preemption disables etc. We're talking ten+ instructions just to increment a per-cpu variable in some pretty hot code. Fix the craziness by just using 'this_cpu_inc()' instead. Suddenly we only need a single 'inc' instruction to increment the statistics. This is quite noticeable in the incredibly hot avc_has_perm_noaudit() function (which triggers all the statistics by virtue of doing an avc_lookup() call). Signed-off-by: Linus Torvalds --- security/selinux/avc.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) (limited to 'security') diff --git a/security/selinux/avc.c b/security/selinux/avc.c index 1d027e29ce8..5971e30e823 100644 --- a/security/selinux/avc.c +++ b/security/selinux/avc.c @@ -38,11 +38,7 @@ #define AVC_CACHE_RECLAIM 16 #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS -#define avc_cache_stats_incr(field) \ -do { \ - per_cpu(avc_cache_stats, get_cpu()).field++; \ - put_cpu(); \ -} while (0) +#define avc_cache_stats_incr(field) this_cpu_inc(avc_cache_stats.field) #else #define avc_cache_stats_incr(field) do {} while (0) #endif -- cgit v1.2.3-18-g5258