diff options
| author | Ganesh Mahendran <opensource.ganesh@gmail.com> | 2017-05-25 15:20:29 +0800 |
|---|---|---|
| committer | Amit Pundir <amit.pundir@linaro.org> | 2017-06-21 16:39:42 +0530 |
| commit | 73fdeacc86c22f05dcc44bf8c256e879dcc8e040 (patch) | |
| tree | 1e951e967f379fb64bd520ee09ca6d71c773bdbc | |
| parent | 71efbfbf131d77d61c61ee1766d80d5ff68a72bf (diff) | |
ANDROID: uid_sys_stats: check previous uid_entry before call find_or_register_uid
Theads in a process are stored in list struct task_struct->thread_group,
so it will be visited continiously in below loop:
do_each_thread(temp, task) {
...
} while_each_thread(temp, task);
I add some log in the loop, we can see below information:
[ 65.033561] uid 1000, uid_entry ffffffc0f2761600
[ 65.033567] uid 1000, uid_entry ffffffc0f2761600
[ 65.033574] uid 1000, uid_entry ffffffc0f2761600
[ 65.033581] uid 1000, uid_entry ffffffc0f2761600
[ 65.033588] uid 1000, uid_entry ffffffc0f2761600
[ 65.033595] uid 1000, uid_entry ffffffc0f2761600
[ 65.033602] uid 1000, uid_entry ffffffc0f2761600
[ 65.033609] uid 1000, uid_entry ffffffc0f2761600
[ 65.033615] uid 1000, uid_entry ffffffc0f2761600
[ 65.033622] uid 1000, uid_entry ffffffc0f2761600
[ 65.033629] uid 1000, uid_entry ffffffc0f2761600
[ 65.033637] uid 1000, uid_entry ffffffc0f2761600
[ 65.033644] uid 1000, uid_entry ffffffc0f2761600
[ 65.033651] uid 1000, uid_entry ffffffc0f2761600
[ 65.033658] uid 1000, uid_entry ffffffc0f2761600
[ 65.033665] uid 1000, uid_entry ffffffc0f2761600
[ 65.033672] uid 1000, uid_entry ffffffc0f2761600
[ 65.033680] uid 1000, uid_entry ffffffc0f2761600
[ 65.033687] uid 1000, uid_entry ffffffc0f2761600
[ 65.033694] uid 1000, uid_entry ffffffc0f2761600
[ 65.033701] uid 1000, uid_entry ffffffc0f2761600
[ 65.033708] uid 1000, uid_entry ffffffc0f2761600
[ 65.033715] uid 1000, uid_entry ffffffc0f2761600
[ 65.033722] uid 1000, uid_entry ffffffc0f2761600
[ 65.033729] uid 1000, uid_entry ffffffc0f2761600
[ 65.033736] uid 1000, uid_entry ffffffc0f2761600
[ 65.033743] uid 1000, uid_entry ffffffc0f2761600
[ 65.033750] uid 1000, uid_entry ffffffc0f2761600
[ 65.033757] uid 1000, uid_entry ffffffc0f2761600
[ 65.033763] uid 1000, uid_entry ffffffc0f2761600
[ 65.033770] uid 1000, uid_entry ffffffc0f2761600
[ 65.033777] uid 1000, uid_entry ffffffc0f2761600
[ 65.033784] uid 1000, uid_entry ffffffc0f2761600
[ 65.033791] uid 1000, uid_entry ffffffc0f2761600
[ 65.033798] uid 1000, uid_entry ffffffc0f2761600
So we can check the previous uid_entry before calling find_or_register_uid
to save time.
Change-Id: I05ec1a1405a80c0a620cb4b4b2f6483dbfde7829
Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
| -rw-r--r-- | drivers/misc/uid_sys_stats.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/misc/uid_sys_stats.c b/drivers/misc/uid_sys_stats.c index 091370f4ea40..3c9d311106cd 100644 --- a/drivers/misc/uid_sys_stats.c +++ b/drivers/misc/uid_sys_stats.c @@ -94,7 +94,7 @@ static struct uid_entry *find_or_register_uid(uid_t uid) static int uid_cputime_show(struct seq_file *m, void *v) { - struct uid_entry *uid_entry; + struct uid_entry *uid_entry = NULL; struct task_struct *task, *temp; struct user_namespace *user_ns = current_user_ns(); cputime_t utime; @@ -112,7 +112,8 @@ static int uid_cputime_show(struct seq_file *m, void *v) read_lock(&tasklist_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 || uid_entry->uid != uid) + uid_entry = find_or_register_uid(uid); if (!uid_entry) { read_unlock(&tasklist_lock); rt_mutex_unlock(&uid_lock); @@ -251,7 +252,7 @@ static void compute_uid_io_bucket_stats(struct io_stats *io_bucket, static void update_io_stats_all_locked(void) { - struct uid_entry *uid_entry; + struct uid_entry *uid_entry = NULL; struct task_struct *task, *temp; struct user_namespace *user_ns = current_user_ns(); unsigned long bkt; @@ -264,7 +265,8 @@ static void update_io_stats_all_locked(void) 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 || uid_entry->uid != uid) + uid_entry = find_or_register_uid(uid); if (!uid_entry) continue; add_uid_io_stats(uid_entry, task, UID_STATE_TOTAL_CURR); |