1 files changed, 18 insertions, 6 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 3d3848fa6324..5e00f1772c20 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -69,6 +69,12 @@ static inline long sync_writeback_pages(void)
 int dirty_background_ratio = 5;
 
 /*
+ * free highmem will not be subtracted from the total free memory
+ * for calculating free ratios if vm_highmem_is_dirtyable is true
+ */
+int vm_highmem_is_dirtyable;
+
+/*
  * The generator of dirty data starts writeback at this percentage
  */
 int vm_dirty_ratio = 10;
@@ -219,7 +225,7 @@ static inline void task_dirties_fraction(struct task_struct *tsk,
  *
  *   dirty -= (dirty/8) * p_{t}
  */
-void task_dirty_limit(struct task_struct *tsk, long *pdirty)
+static void task_dirty_limit(struct task_struct *tsk, long *pdirty)
 {
         long numerator, denominator;
         long dirty = *pdirty;
@@ -287,7 +293,10 @@ static unsigned long determine_dirtyable_memory(void)
         x = global_page_state(NR_FREE_PAGES)
                 + global_page_state(NR_INACTIVE)
                 + global_page_state(NR_ACTIVE);
-        x -= highmem_dirtyable_memory(x);
+
+        if (!vm_highmem_is_dirtyable)
+                x -= highmem_dirtyable_memory(x);
+
         return x + 1;   /* Ensure that we never return 0 */
 }
 
@@ -558,6 +567,7 @@ static void background_writeout(unsigned long _min_pages)
                         global_page_state(NR_UNSTABLE_NFS) < background_thresh
                                 && min_pages <= 0)
                         break;
+                wbc.more_io = 0;
                 wbc.encountered_congestion = 0;
                 wbc.nr_to_write = MAX_WRITEBACK_PAGES;
                 wbc.pages_skipped = 0;
@@ -565,8 +575,9 @@ static void background_writeout(unsigned long _min_pages)
                 min_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write;
                 if (wbc.nr_to_write > 0 || wbc.pages_skipped > 0) {
                         /* Wrote less than expected */
-                        congestion_wait(WRITE, HZ/10);
-                        if (!wbc.encountered_congestion)
+                        if (wbc.encountered_congestion || wbc.more_io)
+                                congestion_wait(WRITE, HZ/10);
+                        else
                                 break;
                 }
         }
@@ -631,11 +642,12 @@ static void wb_kupdate(unsigned long arg)
                         global_page_state(NR_UNSTABLE_NFS) +
                         (inodes_stat.nr_inodes - inodes_stat.nr_unused);
         while (nr_to_write > 0) {
+                wbc.more_io = 0;
                 wbc.encountered_congestion = 0;
                 wbc.nr_to_write = MAX_WRITEBACK_PAGES;
                 writeback_inodes(&wbc);
                 if (wbc.nr_to_write > 0) {
-                        if (wbc.encountered_congestion)
+                        if (wbc.encountered_congestion || wbc.more_io)
                                 congestion_wait(WRITE, HZ/10);
                         else
                                 break;  /* All the old data is written */
@@ -1064,7 +1076,7 @@ static int __set_page_dirty(struct page *page)
         return 0;
 }
 
-int fastcall set_page_dirty(struct page *page)
+int set_page_dirty(struct page *page)
 {
         int ret = __set_page_dirty(page);
         if (ret)