1 files changed, 71 insertions, 6 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 5e00f1772c20..789b6adbef37 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -164,9 +164,20 @@ int dirty_ratio_handler(struct ctl_table *table, int write,
  */
 static inline void __bdi_writeout_inc(struct backing_dev_info *bdi)
 {
-        __prop_inc_percpu(&vm_completions, &bdi->completions);
+        __prop_inc_percpu_max(&vm_completions, &bdi->completions,
+                              bdi->max_prop_frac);
 }
 
+void bdi_writeout_inc(struct backing_dev_info *bdi)
+{
+        unsigned long flags;
+
+        local_irq_save(flags);
+        __bdi_writeout_inc(bdi);
+        local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(bdi_writeout_inc);
+
 static inline void task_dirty_inc(struct task_struct *tsk)
 {
         prop_inc_single(&vm_dirties, &tsk->dirties);
@@ -200,7 +211,8 @@ clip_bdi_dirty_limit(struct backing_dev_info *bdi, long dirty, long *pbdi_dirty)
         avail_dirty = dirty -
                 (global_page_state(NR_FILE_DIRTY) +
                  global_page_state(NR_WRITEBACK) +
-                 global_page_state(NR_UNSTABLE_NFS));
+                 global_page_state(NR_UNSTABLE_NFS) +
+                 global_page_state(NR_WRITEBACK_TEMP));
 
         if (avail_dirty < 0)
                 avail_dirty = 0;
@@ -243,6 +255,55 @@ 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);
+        if (min_ratio > bdi->max_ratio) {
+                ret = -EINVAL;
+        } else {
+                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;
+}
+
+int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned max_ratio)
+{
+        unsigned long flags;
+        int ret = 0;
+
+        if (max_ratio > 100)
+                return -EINVAL;
+
+        spin_lock_irqsave(&bdi_lock, flags);
+        if (bdi->min_ratio > max_ratio) {
+                ret = -EINVAL;
+        } else {
+                bdi->max_ratio = max_ratio;
+                bdi->max_prop_frac = (PROP_FRAC_BASE * max_ratio) / 100;
+        }
+        spin_unlock_irqrestore(&bdi_lock, flags);
+
+        return ret;
+}
+EXPORT_SYMBOL(bdi_set_max_ratio);
+
+/*
  * Work out the current dirty-memory clamping and background writeout
  * thresholds.
  *
@@ -300,7 +361,7 @@ static unsigned long determine_dirtyable_memory(void)
         return x + 1;   /* Ensure that we never return 0 */
 }
 
-static void
+void
 get_dirty_limits(long *pbackground, long *pdirty, long *pbdi_dirty,
                  struct backing_dev_info *bdi)
 {
@@ -330,7 +391,7 @@ 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 +399,12 @@ 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;
+                if (bdi_dirty > (dirty * bdi->max_ratio) / 100)
+                        bdi_dirty = dirty * bdi->max_ratio / 100;
 
                 *pbdi_dirty = bdi_dirty;
                 clip_bdi_dirty_limit(bdi, dirty, pbdi_dirty);
@@ -1192,7 +1257,7 @@ int test_clear_page_writeback(struct page *page)
                         radix_tree_tag_clear(&mapping->page_tree,
                                                 page_index(page),
                                                 PAGECACHE_TAG_WRITEBACK);
-                        if (bdi_cap_writeback_dirty(bdi)) {
+                        if (bdi_cap_account_writeback(bdi)) {
                                 __dec_bdi_stat(bdi, BDI_WRITEBACK);
                                 __bdi_writeout_inc(bdi);
                         }
@@ -1221,7 +1286,7 @@ int test_set_page_writeback(struct page *page)
                         radix_tree_tag_set(&mapping->page_tree,
                                                 page_index(page),
                                                 PAGECACHE_TAG_WRITEBACK);
-                        if (bdi_cap_writeback_dirty(bdi))
+                        if (bdi_cap_account_writeback(bdi))
                                 __inc_bdi_stat(bdi, BDI_WRITEBACK);
                 }
                 if (!PageDirty(page))