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| author | Christoph Lameter <christoph@lameter.com> | 2005-06-23 00:10:05 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-06-23 09:45:30 -0700 |
| commit | 71a2224d7d1cefc23a1ac80bba421cc069cc3257 (patch) | |
| tree | 3b3bc52e592484f008b4f1035a0d2e9e16b029f3 /kernel/exit.c | |
| parent | b030a4dd609e167da7f73c2d1fa5af864a0aea17 (diff) | |
| download | lwn-71a2224d7d1cefc23a1ac80bba421cc069cc3257.tar.gz lwn-71a2224d7d1cefc23a1ac80bba421cc069cc3257.zip | |
[PATCH] Optimize sys_times for a single thread process
Avoid taking the tasklist_lock in sys_times if the process is single
threaded. In a NUMA system taking the tasklist_lock may cause a bouncing
cacheline if multiple independent processes continually call sys_times to
measure their performance.
Signed-off-by: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/exit.c')
| -rw-r--r-- | kernel/exit.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index c2bdf6fb61a5..3ebcd60a19c6 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -72,6 +72,11 @@ repeat: BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children)); __exit_signal(p); __exit_sighand(p); + /* + * Note that the fastpath in sys_times depends on __exit_signal having + * updated the counters before a task is removed from the tasklist of + * the process by __unhash_process. + */ __unhash_process(p); /* |