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-rw-r--r--mm/page-writeback.c27
1 files changed, 26 insertions, 1 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index e5b6b1190a95..4ac077f4269c 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -243,6 +243,29 @@ static void task_dirty_limit(struct task_struct *tsk, long *pdirty)
}
/*
+ *
+ */
+static DEFINE_SPINLOCK(bdi_lock);
+static unsigned int bdi_min_ratio;
+
+int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio)
+{
+ int ret = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&bdi_lock, flags);
+ min_ratio -= bdi->min_ratio;
+ if (bdi_min_ratio + min_ratio < 100) {
+ bdi_min_ratio += min_ratio;
+ bdi->min_ratio += min_ratio;
+ } else
+ ret = -EINVAL;
+ spin_unlock_irqrestore(&bdi_lock, flags);
+
+ return ret;
+}
+
+/*
* Work out the current dirty-memory clamping and background writeout
* thresholds.
*
@@ -330,7 +353,7 @@ get_dirty_limits(long *pbackground, long *pdirty, long *pbdi_dirty,
*pdirty = dirty;
if (bdi) {
- u64 bdi_dirty = dirty;
+ u64 bdi_dirty;
long numerator, denominator;
/*
@@ -338,8 +361,10 @@ get_dirty_limits(long *pbackground, long *pdirty, long *pbdi_dirty,
*/
bdi_writeout_fraction(bdi, &numerator, &denominator);
+ bdi_dirty = (dirty * (100 - bdi_min_ratio)) / 100;
bdi_dirty *= numerator;
do_div(bdi_dirty, denominator);
+ bdi_dirty += (dirty * bdi->min_ratio) / 100;
*pbdi_dirty = bdi_dirty;
clip_bdi_dirty_limit(bdi, dirty, pbdi_dirty);