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

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.

Link: https://lkml.kernel.org/r/20221119005215.3052436-3-shr@devkernel.io
Signed-off-by: Stefan Roesch <shr@devkernel.io>
Cc: Chris Mason <clm@meta.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Stefan Roesch 2022-11-18 16:51:57 -08:00 committed by Andrew Morton
parent 8e9d5ead86
commit 27bbe9d48d

View File

@ -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);