aboutsummaryrefslogtreecommitdiff
path: root/kernel/taskstats.c
diff options
context:
space:
mode:
authorOleg Nesterov <oleg@tv-sign.ru>2006-12-06 20:36:50 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-07 08:39:34 -0800
commit128fb95650b3273a8dc9ba5514b6fe7db8ea30bf (patch)
tree82e8070451edbd7421b6176083658f5f2b997b58 /kernel/taskstats.c
parent38da288b8ba2b07b4e07165027e650b61d7c8ffc (diff)
downloadvexpress-lsk-128fb95650b3273a8dc9ba5514b6fe7db8ea30bf.tar.gz
[PATCH] taskstats_exit_alloc: optimize/simplify
If there are no listeners, every task does unneeded kmem_cache alloc/free on exit. We don't need listeners->sem for 'if (!list_empty())' check. Yes, we may have a false positive, but this doesn't differ from the case when the listener is unregistered after we drop the semaphore. So we don't need to do allocation beforehand. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Balbir Singh <balbir@in.ibm.com> Acked-by: Shailabh Nagar <nagar@watson.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/taskstats.c')
-rw-r--r--kernel/taskstats.c17
1 files changed, 4 insertions, 13 deletions
diff --git a/kernel/taskstats.c b/kernel/taskstats.c
index f5f92014ae9..d9d7c357623 100644
--- a/kernel/taskstats.c
+++ b/kernel/taskstats.c
@@ -416,7 +416,6 @@ err:
void taskstats_exit_alloc(struct taskstats **ptidstats, unsigned int *mycpu)
{
struct listener_list *listeners;
- struct taskstats *tmp;
/*
* This is the cpu on which the task is exiting currently and will
* be the one for which the exit event is sent, even if the cpu
@@ -424,19 +423,11 @@ void taskstats_exit_alloc(struct taskstats **ptidstats, unsigned int *mycpu)
*/
*mycpu = raw_smp_processor_id();
- *ptidstats = NULL;
- tmp = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
- if (!tmp)
- return;
-
listeners = &per_cpu(listener_array, *mycpu);
- down_read(&listeners->sem);
- if (!list_empty(&listeners->list)) {
- *ptidstats = tmp;
- tmp = NULL;
- }
- up_read(&listeners->sem);
- kfree(tmp);
+
+ *ptidstats = NULL;
+ if (!list_empty(&listeners->list))
+ *ptidstats = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
}
/* Send pid data out on exit */