mm: add strictlimit knob

[karo-tx-linux.git] / mm / backing-dev.c

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 6dc4580df2af040b10bc10a5f9c423becc3ff47e..a00a2e819a78385c6f3c7335a9428250ba118606 100644 (file)
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -219,11 +219,46 @@ 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);