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authorChristoph Lameter <christoph@lameter.com>2005-06-23 00:10:05 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-23 09:45:30 -0700
commit71a2224d7d1cefc23a1ac80bba421cc069cc3257 (patch)
tree3b3bc52e592484f008b4f1035a0d2e9e16b029f3 /kernel/exit.c
parentb030a4dd609e167da7f73c2d1fa5af864a0aea17 (diff)
downloadop-kernel-dev-71a2224d7d1cefc23a1ac80bba421cc069cc3257.zip
op-kernel-dev-71a2224d7d1cefc23a1ac80bba421cc069cc3257.tar.gz
[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.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index c2bdf6f..3ebcd60 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);
/*
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