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

This adds the new knob max_bytes to specify a dirty memory limit for the
corresponding bdi. The specified bytes value is converted to a ratio.

Link: https://lkml.kernel.org/r/20221119005215.3052436-9-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 16:52:03 -08:00 committed by Andrew Morton
parent 1bf27e98d2
commit c56e049a5e

View File

@ -199,6 +199,34 @@ static ssize_t max_ratio_store(struct device *dev,
}
BDI_SHOW(max_ratio, bdi->max_ratio / BDI_RATIO_SCALE)
static ssize_t max_bytes_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct backing_dev_info *bdi = dev_get_drvdata(dev);
return sysfs_emit(buf, "%llu\n", bdi_get_max_bytes(bdi));
}
static ssize_t max_bytes_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
struct backing_dev_info *bdi = dev_get_drvdata(dev);
u64 bytes;
ssize_t ret;
ret = kstrtoull(buf, 10, &bytes);
if (ret < 0)
return ret;
ret = bdi_set_max_bytes(bdi, bytes);
if (!ret)
ret = count;
return ret;
}
DEVICE_ATTR_RW(max_bytes);
static ssize_t stable_pages_required_show(struct device *dev,
struct device_attribute *attr,
char *buf)
@ -241,6 +269,7 @@ static struct attribute *bdi_dev_attrs[] = {
&dev_attr_read_ahead_kb.attr,
&dev_attr_min_ratio.attr,
&dev_attr_max_ratio.attr,
&dev_attr_max_bytes.attr,
&dev_attr_stable_pages_required.attr,
&dev_attr_strict_limit.attr,
NULL,