ANDROID: cpufreq: times: track per-uid time in state

Add /proc/uid_time_in_state showing per uid/frequency/cluster
times. Allow uid removal through /proc/uid_cputime/remove_uid_range.

Signed-off-by: Connor O'Brien <connoro@google.com>
Bug: 72339335
Test: Read /proc/uid_time_in_state
Change-Id: I20ba3546a27c25b7e7991e2a86986e158aafa58c

drivers/cpufreq/cpufreq_times.c

@@ -15,14 +15,30 @@
 
 #include <linux/cpufreq.h>
 #include <linux/cpufreq_times.h>
+#include <linux/hashtable.h>
+#include <linux/init.h>
 #include <linux/jiffies.h>
+#include <linux/proc_fs.h>
 #include <linux/sched.h>
 #include <linux/seq_file.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/threads.h>
 
+#define UID_HASH_BITS 10
+
+static DECLARE_HASHTABLE(uid_hash_table, UID_HASH_BITS);
+
 static DEFINE_SPINLOCK(task_time_in_state_lock); /* task->time_in_state */
+static DEFINE_SPINLOCK(uid_lock); /* uid_hash_table */
+
+struct uid_entry {
+	uid_t uid;
+	unsigned int max_state;
+	struct hlist_node hash;
+	struct rcu_head rcu;
+	u64 time_in_state[0];
+};
 
 /**
  * struct cpu_freqs - per-cpu frequency information
@@ -42,6 +58,137 @@ static struct cpu_freqs *all_freqs[NR_CPUS];
 
 static unsigned int next_offset;
 
+/* Caller must hold uid lock */
+static struct uid_entry *find_uid_entry_locked(uid_t uid)
+{
+	struct uid_entry *uid_entry;
+
+	hash_for_each_possible(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_or_register_uid_locked(uid_t uid)
+{
+	struct uid_entry *uid_entry, *temp;
+	unsigned int max_state = READ_ONCE(next_offset);
+	size_t alloc_size = sizeof(*uid_entry) + max_state *
+		sizeof(uid_entry->time_in_state[0]);
+
+	uid_entry = find_uid_entry_locked(uid);
+	if (uid_entry) {
+		if (uid_entry->max_state == max_state)
+			return uid_entry;
+		/* uid_entry->time_in_state is too small to track all freqs, so
+		 * expand it.
+		 */
+		temp = __krealloc(uid_entry, alloc_size, GFP_ATOMIC);
+		if (!temp)
+			return uid_entry;
+		temp->max_state = max_state;
+		memset(temp->time_in_state + uid_entry->max_state, 0,
+		       (max_state - uid_entry->max_state) *
+		       sizeof(uid_entry->time_in_state[0]));
+		if (temp != uid_entry) {
+			hlist_replace_rcu(&uid_entry->hash, &temp->hash);
+			kfree_rcu(uid_entry, rcu);
+		}
+		return temp;
+	}
+
+	uid_entry = kzalloc(alloc_size, GFP_ATOMIC);
+	if (!uid_entry)
+		return NULL;
+
+	uid_entry->uid = uid;
+	uid_entry->max_state = max_state;
+
+	hash_add_rcu(uid_hash_table, &uid_entry->hash, uid);
+
+	return uid_entry;
+}
+
+static bool freq_index_invalid(unsigned int index)
+{
+	unsigned int cpu;
+	struct cpu_freqs *freqs;
+
+	for_each_possible_cpu(cpu) {
+		freqs = all_freqs[cpu];
+		if (!freqs || index < freqs->offset ||
+		    freqs->offset + freqs->max_state <= index)
+			continue;
+		return freqs->freq_table[index - freqs->offset] ==
+			CPUFREQ_ENTRY_INVALID;
+	}
+	return true;
+}
+
+static void *uid_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	if (*pos >= HASH_SIZE(uid_hash_table))
+		return NULL;
+
+	return &uid_hash_table[*pos];
+}
+
+static void *uid_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	(*pos)++;
+
+	if (*pos >= HASH_SIZE(uid_hash_table))
+		return NULL;
+
+	return &uid_hash_table[*pos];
+}
+
+static void uid_seq_stop(struct seq_file *seq, void *v) { }
+
+static int uid_time_in_state_seq_show(struct seq_file *m, void *v)
+{
+	struct uid_entry *uid_entry;
+	struct cpu_freqs *freqs, *last_freqs = NULL;
+	int i, cpu;
+
+	if (v == uid_hash_table) {
+		seq_puts(m, "uid:");
+		for_each_possible_cpu(cpu) {
+			freqs = all_freqs[cpu];
+			if (!freqs || freqs == last_freqs)
+				continue;
+			last_freqs = freqs;
+			for (i = 0; i < freqs->max_state; i++) {
+				if (freqs->freq_table[i] ==
+				    CPUFREQ_ENTRY_INVALID)
+					continue;
+				seq_printf(m, " %d", freqs->freq_table[i]);
+			}
+		}
+		seq_putc(m, '\n');
+	}
+
+	rcu_read_lock();
+
+	hlist_for_each_entry_rcu(uid_entry, (struct hlist_head *)v, hash) {
+		if (uid_entry->max_state)
+			seq_printf(m, "%d:", uid_entry->uid);
+		for (i = 0; i < uid_entry->max_state; ++i) {
+			if (freq_index_invalid(i))
+				continue;
+			seq_printf(m, " %lu", (unsigned long)nsec_to_clock_t(
+					   uid_entry->time_in_state[i]));
+		}
+		if (uid_entry->max_state)
+			seq_putc(m, '\n');
+	}
+
+	rcu_read_unlock();
+	return 0;
+}
+
 void cpufreq_task_times_init(struct task_struct *p)
 {
 	void *temp;
@@ -87,6 +234,9 @@ void cpufreq_task_times_exit(struct task_struct *p)
 	unsigned long flags;
 	void *temp;
 
+	if (!p->time_in_state)
+		return;
+
 	spin_lock_irqsave(&task_time_in_state_lock, flags);
 	temp = p->time_in_state;
 	p->time_in_state = NULL;
@@ -130,7 +280,9 @@ void cpufreq_acct_update_power(struct task_struct *p, u64 cputime)
 {
 	unsigned long flags;
 	unsigned int state;
+	struct uid_entry *uid_entry;
 	struct cpu_freqs *freqs = all_freqs[task_cpu(p)];
+	uid_t uid = from_kuid_munged(current_user_ns(), task_uid(p));
 
 	if (!freqs || p->flags & PF_EXITING)
 		return;
@@ -142,6 +294,12 @@ void cpufreq_acct_update_power(struct task_struct *p, u64 cputime)
 	    p->time_in_state)
 		p->time_in_state[state] += cputime;
 	spin_unlock_irqrestore(&task_time_in_state_lock, flags);
+
+	spin_lock_irqsave(&uid_lock, flags);
+	uid_entry = find_or_register_uid_locked(uid);
+	if (uid_entry && state < uid_entry->max_state)
+		uid_entry->time_in_state[state] += cputime;
+	spin_unlock_irqrestore(&uid_lock, flags);
 }
 
 void cpufreq_times_create_policy(struct cpufreq_policy *policy)
@@ -183,6 +341,27 @@ void cpufreq_times_create_policy(struct cpufreq_policy *policy)
 		all_freqs[cpu] = freqs;
 }
 
+void cpufreq_task_times_remove_uids(uid_t uid_start, uid_t uid_end)
+{
+	struct uid_entry *uid_entry;
+	struct hlist_node *tmp;
+	unsigned long flags;
+
+	spin_lock_irqsave(&uid_lock, flags);
+
+	for (; uid_start <= uid_end; uid_start++) {
+		hash_for_each_possible_safe(uid_hash_table, uid_entry, tmp,
+			hash, uid_start) {
+			if (uid_start == uid_entry->uid) {
+				hash_del_rcu(&uid_entry->hash);
+				kfree_rcu(uid_entry, rcu);
+			}
+		}
+	}
+
+	spin_unlock_irqrestore(&uid_lock, flags);
+}
+
 void cpufreq_times_record_transition(struct cpufreq_freqs *freq)
 {
 	int index;
@@ -202,3 +381,32 @@ void cpufreq_times_record_transition(struct cpufreq_freqs *freq)
 
 	cpufreq_cpu_put(policy);
 }
+
+static const struct seq_operations uid_time_in_state_seq_ops = {
+	.start = uid_seq_start,
+	.next = uid_seq_next,
+	.stop = uid_seq_stop,
+	.show = uid_time_in_state_seq_show,
+};
+
+static int uid_time_in_state_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &uid_time_in_state_seq_ops);
+}
+
+static const struct file_operations uid_time_in_state_fops = {
+	.open		= uid_time_in_state_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static int __init cpufreq_times_init(void)
+{
+	proc_create_data("uid_time_in_state", 0444, NULL,
+			 &uid_time_in_state_fops, NULL);
+
+	return 0;
+}
+
+early_initcall(cpufreq_times_init);

drivers/misc/uid_sys_stats.c

@@ -14,6 +14,7 @@
  */
 
 #include <linux/atomic.h>
+#include <linux/cpufreq_times.h>
 #include <linux/err.h>
 #include <linux/hashtable.h>
 #include <linux/init.h>
@@ -419,6 +420,10 @@ static ssize_t uid_remove_write(struct file *file,
 		kstrtol(end_uid, 10, &uid_end) != 0) {
 		return -EINVAL;
 	}
+
+	/* Also remove uids from /proc/uid_time_in_state */
+	cpufreq_task_times_remove_uids(uid_start, uid_end);
+
 	rt_mutex_lock(&uid_lock);
 
 	for (; uid_start <= uid_end; uid_start++) {

include/linux/cpufreq_times.h

@@ -27,9 +27,12 @@ int proc_time_in_state_show(struct seq_file *m, struct pid_namespace *ns,
 void cpufreq_acct_update_power(struct task_struct *p, u64 cputime);
 void cpufreq_times_create_policy(struct cpufreq_policy *policy);
 void cpufreq_times_record_transition(struct cpufreq_freqs *freq);
+void cpufreq_task_times_remove_uids(uid_t uid_start, uid_t uid_end);
 #else
 static inline void cpufreq_times_create_policy(struct cpufreq_policy *policy) {}
 static inline void cpufreq_times_record_transition(
 	struct cpufreq_freqs *freq) {}
+static inline void cpufreq_task_times_remove_uids(uid_t uid_start,
+						  uid_t uid_end) {}
 #endif /* CONFIG_CPU_FREQ_TIMES */
 #endif /* _LINUX_CPUFREQ_TIMES_H */