[PATCH] taskstats: cleanup ->signal->stats allocation
Allocate ->signal->stats on demand in taskstats_exit(), this allows us to
remove taskstats_tgid_alloc() (the last non-trivial inline) from taskstat's
public interface.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/taskstats.c b/kernel/taskstats.c
index 2654886..7d793d6 100644
--- a/kernel/taskstats.c
+++ b/kernel/taskstats.c
@@ -412,6 +412,30 @@
return rc;
}
+static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk)
+{
+ struct signal_struct *sig = tsk->signal;
+ struct taskstats *stats;
+
+ if (sig->stats || thread_group_empty(tsk))
+ goto ret;
+
+ /* No problem if kmem_cache_zalloc() fails */
+ stats = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
+
+ spin_lock_irq(&tsk->sighand->siglock);
+ if (!sig->stats) {
+ sig->stats = stats;
+ stats = NULL;
+ }
+ spin_unlock_irq(&tsk->sighand->siglock);
+
+ if (stats)
+ kmem_cache_free(taskstats_cache, stats);
+ret:
+ return sig->stats;
+}
+
/* Send pid data out on exit */
void taskstats_exit(struct task_struct *tsk, int group_dead)
{
@@ -433,7 +457,7 @@
size = nla_total_size(sizeof(u32)) +
nla_total_size(sizeof(struct taskstats)) + nla_total_size(0);
- is_thread_group = (tsk->signal->stats != NULL);
+ is_thread_group = !!taskstats_tgid_alloc(tsk);
if (is_thread_group) {
/* PID + STATS + TGID + STATS */
size = 2 * size;
