diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-05-19 18:59:47 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-05-19 18:59:47 -0700 |
| commit | 044aea9b83614948c98564000db07d1d32b2d29b (patch) | |
| tree | b1f13ed2f4bb0bd40f7915a89aafaf449b6145cd | |
| parent | 39ab05c8e0b519ff0a04a869f065746e6e8c3d95 (diff) | |
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 <torvalds@linux-foundation.org>
| -rw-r--r-- | security/selinux/avc.c | 6 |
1 files changed, 1 insertions, 5 deletions
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 |