mm: add /sys/class/bdi/<bdi>/min_ratio_fine knob

This adds the min_ratio_fine knob. The knob specifies the values not based on 1 of 100, but instead 1 per million. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Stefan Roesch <[email protected]> Cc: Chris Mason <[email protected]> Cc: Jens Axboe <[email protected]> Signed-off-by: Andrew Morton <[email protected]>
wafgo · Nov 30, 2022 · ad3e6da · ad3e6da
1 parent 2c44af4
commit ad3e6da
Showing 1 changed file with 20 additions and 0 deletions.
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
@@ -180,6 +180,25 @@ static ssize_t min_ratio_store(struct device *dev,
 }
 BDI_SHOW(min_ratio, bdi->min_ratio / BDI_RATIO_SCALE)
 
+static ssize_t min_ratio_fine_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct backing_dev_info *bdi = dev_get_drvdata(dev);
+	unsigned int ratio;
+	ssize_t ret;
+
+	ret = kstrtouint(buf, 10, &ratio);
+	if (ret < 0)
+		return ret;
+
+	ret = bdi_set_min_ratio_no_scale(bdi, ratio);
+	if (!ret)
+		ret = count;
+
+	return ret;
+}
+BDI_SHOW(min_ratio_fine, bdi->min_ratio)
+
 static ssize_t max_ratio_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t count)
 {
@@ -315,6 +334,7 @@ static DEVICE_ATTR_RW(strict_limit);
 static struct attribute *bdi_dev_attrs[] = {
 	&dev_attr_read_ahead_kb.attr,
 	&dev_attr_min_ratio.attr,
+	&dev_attr_min_ratio_fine.attr,
 	&dev_attr_max_ratio.attr,
 	&dev_attr_max_ratio_fine.attr,
 	&dev_attr_min_bytes.attr,