cpuquiet: Add Sysfs node for nr_run_thresholds

Added sysfs node that exposes the nr_runnable threshold at which cores
are quiesenced/woken up. To write into this node:

echo 1core# 2core# ... n_core# > nr_run_thresholds

Bug 1427140

Change-Id: I7cabd63692cf92f7fe8d1064437b1d73002d4ba5
Signed-off-by: Sai Gurrappadi <sgurrappadi@nvidia.com>
Reviewed-on: http://git-master/r/369017
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Diwakar Tundlam <dtundlam@nvidia.com>

1 files changed, 51 insertions, 0 deletions

diff --git a/drivers/cpuquiet/governors/runnable_threads.c b/drivers/cpuquiet/governors/runnable_threads.c
index 77ce4b88566b..f670d1a1aec5 100644
--- a/drivers/cpuquiet/governors/runnable_threads.c
+++ b/drivers/cpuquiet/governors/runnable_threads.c
@@ -198,12 +198,63 @@ static void runnables_work_func(struct work_struct *work)
 	}
 }
 
+#define MAX_BYTES 100
+
+static ssize_t show_thresholds(struct cpuquiet_attribute *attr, char *buf)
+{
+	char buffer[MAX_BYTES];
+	unsigned int i;
+	int size = 0;
+	buffer[0] = 0;
+	for_each_possible_cpu(i) {
+		if (i == ARRAY_SIZE(nr_run_thresholds) - 1)
+			break;
+		if (size >= sizeof(buffer))
+			break;
+		size += snprintf(buffer + size, sizeof(buffer) - size,
+			 "%u->%u core threshold: %u\n",
+			  i + 1, i + 2, nr_run_thresholds[i]);
+	}
+	return snprintf(buf, sizeof(buffer), "%s", buffer);
+}
+
+static ssize_t store_thresholds(struct cpuquiet_attribute *attr,
+				const char *buf, size_t count)
+{
+	int ret, i = 0;
+	char *val, *str, input[MAX_BYTES];
+	unsigned int thresholds[NR_CPUS];
+
+	if (!count || count >= MAX_BYTES)
+		return -EINVAL;
+	strncpy(input, buf, count);
+	input[count] = '\0';
+	str = input;
+	memcpy(thresholds, nr_run_thresholds, sizeof(nr_run_thresholds));
+	while ((val = strsep(&str, " ")) != NULL) {
+		if (*val == '\0')
+			continue;
+		if (i == ARRAY_SIZE(nr_run_thresholds) - 1)
+			break;
+		ret = kstrtouint(val, 10, &thresholds[i]);
+		if (ret)
+			return -EINVAL;
+		i++;
+	}
+
+	memcpy(nr_run_thresholds, thresholds, sizeof(thresholds));
+	return count;
+}
+
 CPQ_BASIC_ATTRIBUTE(sample_rate, 0644, uint);
 CPQ_BASIC_ATTRIBUTE(nr_run_hysteresis, 0644, uint);
+CPQ_ATTRIBUTE_CUSTOM(nr_run_thresholds, 0644,
+			show_thresholds, store_thresholds);
 
 static struct attribute *runnables_attributes[] = {
 	&sample_rate_attr.attr,
 	&nr_run_hysteresis_attr.attr,
+	&nr_run_thresholds_attr.attr,
 	NULL,
 };