ANDROID: cpufreq: Add time_in_state to /proc/uid directories

Add per-uid files that report the data in binary format rather than
text, to allow faster reading & parsing by userspace.

Signed-off-by: Connor O'Brien <connoro@google.com>
Bug: 72339335
Test: compare values to those reported in /proc/uid_time_in_state
Change-Id: I463039ea7f17b842be4c70024fe772539fe2ce02

1 files changed, 49 insertions, 0 deletions

diff --git a/drivers/cpufreq/cpufreq_times.c b/drivers/cpufreq/cpufreq_times.c
index 8e1a97e5728d..b74017f06a8e 100644
--- a/drivers/cpufreq/cpufreq_times.c
+++ b/drivers/cpufreq/cpufreq_times.c
@@ -58,6 +58,19 @@ static struct cpu_freqs *all_freqs[NR_CPUS];
 
 static unsigned int next_offset;
 
+
+/* Caller must hold rcu_read_lock() */
+static struct uid_entry *find_uid_entry_rcu(uid_t uid)
+{
+	struct uid_entry *uid_entry;
+
+	hash_for_each_possible_rcu(uid_hash_table, uid_entry, hash, uid) {
+		if (uid_entry->uid == uid)
+			return uid_entry;
+	}
+	return NULL;
+}
+
 /* Caller must hold uid lock */
 static struct uid_entry *find_uid_entry_locked(uid_t uid)
 {
@@ -125,6 +138,36 @@ static bool freq_index_invalid(unsigned int index)
 	return true;
 }
 
+static int single_uid_time_in_state_show(struct seq_file *m, void *ptr)
+{
+	struct uid_entry *uid_entry;
+	unsigned int i;
+	u64 time;
+	uid_t uid = from_kuid_munged(current_user_ns(), *(kuid_t *)m->private);
+
+	if (uid == overflowuid)
+		return -EINVAL;
+
+	rcu_read_lock();
+
+	uid_entry = find_uid_entry_rcu(uid);
+	if (!uid_entry) {
+		rcu_read_unlock();
+		return 0;
+	}
+
+	for (i = 0; i < uid_entry->max_state; ++i) {
+		if (freq_index_invalid(i))
+			continue;
+		time = cputime_to_clock_t(uid_entry->time_in_state[i]);
+		seq_write(m, &time, sizeof(time));
+	}
+
+	rcu_read_unlock();
+
+	return 0;
+}
+
 static void *uid_seq_start(struct seq_file *seq, loff_t *pos)
 {
 	if (*pos >= HASH_SIZE(uid_hash_table))
@@ -389,6 +432,12 @@ static int uid_time_in_state_open(struct inode *inode, struct file *file)
 	return seq_open(file, &uid_time_in_state_seq_ops);
 }
 
+int single_uid_time_in_state_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, single_uid_time_in_state_show,
+			&(inode->i_uid));
+}
+
 static const struct file_operations uid_time_in_state_fops = {
 	.open		= uid_time_in_state_open,
 	.read		= seq_read,