Add a new knob to /sys/class/bdi/<bdi>/strict_limit. This new knob
allows to set/unset the flag BDI_CAP_STRICTLIMIT in the bdi
capabilities.
Signed-off-by: Stefan Roesch <shr@xxxxxxxxxxxx>
---
mm/backing-dev.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index c30419a5e119..a0899cce72ef 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -209,11 +209,40 @@ static ssize_t stable_pages_required_show(struct device *dev,
}
static DEVICE_ATTR_RO(stable_pages_required);
+static ssize_t strict_limit_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 strict_limit;
+ ssize_t ret;
+
+ ret = kstrtouint(buf, 10, &strict_limit);
+ if (ret < 0)
+ return ret;
+
+ ret = bdi_set_strict_limit(bdi, strict_limit);
+ if (!ret)
+ ret = count;
+
+ return ret;
+}
+
+static ssize_t strict_limit_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct backing_dev_info *bdi = dev_get_drvdata(dev);
+
+ return sysfs_emit(buf, "%d\n",
+ !!(bdi->capabilities & BDI_CAP_STRICTLIMIT));
+}
+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_max_ratio.attr,
&dev_attr_stable_pages_required.attr,
+ &dev_attr_strict_limit.attr,
NULL,
};
ATTRIBUTE_GROUPS(bdi_dev);
--
2.30.2
