From 9e852762e6d7488db5bb4a7c6494fecc438109b1 Mon Sep 17 00:00:00 2001 From: Wei Wang Date: Mon, 13 Mar 2017 12:22:21 -0700 Subject: [PATCH] uid_sys_stats: change to use rt_mutex We see this happens multiple times in heavy workload in systrace and AMS stuck in uid_lock. Running process: Process 953 Running thread: android.ui State: Uninterruptible Sleep Start: 1,025.628 ms Duration: 27,955.949 ms On CPU: Running instead: system_server Args: {kernel callsite when blocked:: "uid_procstat_write+0xb8/0x144"} Changing to rt_mutex can mitigate the priority inversion Bug: 34991231 Bug: 34193533 Test: on marlin Change-Id: I28eb3971331cea60b1075740c792ab87d103262c Signed-off-by: Wei Wang Signed-off-by: Francisco Franco --- drivers/misc/uid_sys_stats.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-) diff --git a/drivers/misc/uid_sys_stats.c b/drivers/misc/uid_sys_stats.c index a6acc3e4646..e16adc556a6 100644 --- a/drivers/misc/uid_sys_stats.c +++ b/drivers/misc/uid_sys_stats.c @@ -25,11 +25,12 @@ #include #include #include +#include #define UID_HASH_BITS 10 DECLARE_HASHTABLE(hash_table, UID_HASH_BITS); -static DEFINE_MUTEX(uid_lock); +static DEFINE_RT_MUTEX(uid_lock); static struct proc_dir_entry *cpu_parent; static struct proc_dir_entry *io_parent; static struct proc_dir_entry *proc_parent; @@ -100,7 +101,7 @@ static int uid_cputime_show(struct seq_file *m, void *v) cputime_t stime; unsigned long bkt; - mutex_lock(&uid_lock); + rt_mutex_lock(&uid_lock); hash_for_each(hash_table, bkt, uid_entry, hash) { uid_entry->active_stime = 0; @@ -114,7 +115,7 @@ static int uid_cputime_show(struct seq_file *m, void *v) current_user_ns(), task_uid(task))); if (!uid_entry) { read_unlock(&tasklist_lock); - mutex_unlock(&uid_lock); + rt_mutex_unlock(&uid_lock); pr_err("%s: failed to find the uid_entry for uid %d\n", __func__, from_kuid_munged(current_user_ns(), task_uid(task))); @@ -143,7 +144,7 @@ static int uid_cputime_show(struct seq_file *m, void *v) total_power); } - mutex_unlock(&uid_lock); + rt_mutex_unlock(&uid_lock); return 0; } @@ -190,7 +191,7 @@ static ssize_t uid_remove_write(struct file *file, kstrtol(end_uid, 10, &uid_end) != 0) { return -EINVAL; } - mutex_lock(&uid_lock); + rt_mutex_lock(&uid_lock); for (; uid_start <= uid_end; uid_start++) { hash_for_each_possible_safe(hash_table, uid_entry, tmp, @@ -202,7 +203,7 @@ static ssize_t uid_remove_write(struct file *file, } } - mutex_unlock(&uid_lock); + rt_mutex_unlock(&uid_lock); return count; } @@ -251,7 +252,7 @@ static void update_io_stats_locked(void) struct io_stats *io_bucket, *io_curr, *io_last; unsigned long bkt; - BUG_ON(!mutex_is_locked(&uid_lock)); + BUG_ON(!rt_mutex_is_locked(&uid_lock)); hash_for_each(hash_table, bkt, uid_entry, hash) memset(&uid_entry->io[UID_STATE_TOTAL_CURR], 0, @@ -293,7 +294,7 @@ static int uid_io_show(struct seq_file *m, void *v) struct uid_entry *uid_entry; unsigned long bkt; - mutex_lock(&uid_lock); + rt_mutex_lock(&uid_lock); update_io_stats_locked(); @@ -312,7 +313,7 @@ static int uid_io_show(struct seq_file *m, void *v) uid_entry->io[UID_STATE_BACKGROUND].fsync); } - mutex_unlock(&uid_lock); + rt_mutex_unlock(&uid_lock); return 0; } @@ -357,16 +358,16 @@ static ssize_t uid_procstat_write(struct file *file, if (state != UID_STATE_BACKGROUND && state != UID_STATE_FOREGROUND) return -EINVAL; - mutex_lock(&uid_lock); + rt_mutex_lock(&uid_lock); uid_entry = find_or_register_uid(uid); if (!uid_entry) { - mutex_unlock(&uid_lock); + rt_mutex_unlock(&uid_lock); return -EINVAL; } if (uid_entry->state == state) { - mutex_unlock(&uid_lock); + rt_mutex_unlock(&uid_lock); return count; } @@ -374,7 +375,7 @@ static ssize_t uid_procstat_write(struct file *file, uid_entry->state = state; - mutex_unlock(&uid_lock); + rt_mutex_unlock(&uid_lock); return count; } @@ -396,7 +397,7 @@ static int process_notifier(struct notifier_block *self, if (!task) return NOTIFY_OK; - mutex_lock(&uid_lock); + rt_mutex_lock(&uid_lock); uid = from_kuid_munged(current_user_ns(), task_uid(task)); uid_entry = find_or_register_uid(uid); if (!uid_entry) { @@ -414,7 +415,7 @@ static int process_notifier(struct notifier_block *self, clean_uid_io_last_stats(uid_entry, task); exit: - mutex_unlock(&uid_lock); + rt_mutex_unlock(&uid_lock); return NOTIFY_OK; } -- 2.20.1