Commit 27bbe9d4 authored by Stefan Roesch's avatar Stefan Roesch Committed by Andrew Morton
Browse files

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: default avatarStefan Roesch <shr@devkernel.io>
Cc: Chris Mason <clm@meta.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 8e9d5ead

mm/backing-dev.c

+29 −0
Original line number Diff line number Diff line
@@ -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);