diff options
| author | Stephen Rothwell <sfr@canb.auug.org.au> | 2013-11-28 12:51:51 +1100 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2013-11-28 12:51:51 +1100 |
| commit | 8849a14cba05ff86ad52c3797717bc29217ecf9c (patch) | |
| tree | 3fbdb35785524af9875c9abb8aa817ecb5fdf8d9 | |
| parent | 517797bdc5a443f05db36939372edf612e017e0f (diff) | |
| parent | bee1070cd449f8a9223c1b2f515f59967186db92 (diff) | |
Merge branch 'akpm/master'
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-bdi | 8 | ||||
| -rw-r--r-- | mm/backing-dev.c | 35 |
2 files changed, 43 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-bdi b/Documentation/ABI/testing/sysfs-class-bdi index d773d5697cf5..3187a18af6da 100644 --- a/Documentation/ABI/testing/sysfs-class-bdi +++ b/Documentation/ABI/testing/sysfs-class-bdi @@ -53,3 +53,11 @@ stable_pages_required (read-only) If set, the backing device requires that all pages comprising a write request must not be changed until writeout is complete. + +strictlimit (read-write) + + Forces per-BDI checks for the share of given device in the write-back + cache even before the global background dirty limit is reached. This + is useful in situations where the global limit is much higher than + affordable for given relatively slow (or untrusted) device. Turning + strictlimit on has no visible effect if max_ratio is equal to 100%. diff --git a/mm/backing-dev.c b/mm/backing-dev.c index ce682f7a4f29..4ee1d64b52a2 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -234,11 +234,46 @@ static ssize_t stable_pages_required_show(struct device *dev, } static DEVICE_ATTR_RO(stable_pages_required); +static ssize_t strictlimit_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 val; + ssize_t ret; + + ret = kstrtouint(buf, 10, &val); + if (ret < 0) + return ret; + + switch (val) { + case 0: + bdi->capabilities &= ~BDI_CAP_STRICTLIMIT; + break; + case 1: + bdi->capabilities |= BDI_CAP_STRICTLIMIT; + break; + default: + return -EINVAL; + } + + return count; +} +static ssize_t strictlimit_show(struct device *dev, + struct device_attribute *attr, char *page) +{ + struct backing_dev_info *bdi = dev_get_drvdata(dev); + + return snprintf(page, PAGE_SIZE-1, "%d\n", + !!(bdi->capabilities & BDI_CAP_STRICTLIMIT)); +} +static DEVICE_ATTR_RW(strictlimit); + 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_strictlimit.attr, NULL, }; ATTRIBUTE_GROUPS(bdi_dev); |