From 5d3984c09f1dbc8021b35765c1fb307f6044642b Mon Sep 17 00:00:00 2001 From: Pavankumar Kondeti Date: Wed, 21 Jun 2017 09:22:45 +0530 Subject: ANDROID: uid_sys_stats: Replace tasklist lock with RCU in uid_cputime_show Tasklist lock is acuquired in uid_cputime_show for updating the stats for all tasks in the system. This can potentially disable preemption for several milli seconds. Replace tasklist_lock with RCU read side primitives. Change-Id: Ife69cb577bfdceaae6eb21b9bda09a0fe687e140 Signed-off-by: Pavankumar Kondeti --- drivers/misc/uid_sys_stats.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers') diff --git a/drivers/misc/uid_sys_stats.c b/drivers/misc/uid_sys_stats.c index 091370f4ea40..8bf72cb10cfa 100644 --- a/drivers/misc/uid_sys_stats.c +++ b/drivers/misc/uid_sys_stats.c @@ -109,12 +109,12 @@ static int uid_cputime_show(struct seq_file *m, void *v) uid_entry->active_utime = 0; } - read_lock(&tasklist_lock); + rcu_read_lock(); do_each_thread(temp, task) { uid = from_kuid_munged(user_ns, task_uid(task)); uid_entry = find_or_register_uid(uid); if (!uid_entry) { - read_unlock(&tasklist_lock); + rcu_read_unlock(); rt_mutex_unlock(&uid_lock); pr_err("%s: failed to find the uid_entry for uid %d\n", __func__, uid); @@ -124,7 +124,7 @@ static int uid_cputime_show(struct seq_file *m, void *v) uid_entry->active_utime += utime; uid_entry->active_stime += stime; } while_each_thread(temp, task); - read_unlock(&tasklist_lock); + rcu_read_unlock(); hash_for_each(hash_table, bkt, uid_entry, hash) { cputime_t total_utime = uid_entry->utime + -- cgit v1.2.3