1 files changed, 47 insertions, 46 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 9ab6de82d8e..433fa990fe8 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -146,6 +146,7 @@ static struct prop_descriptor vm_completions;
  * We make sure that the background writeout level is below the adjusted
  * clamping level.
  */
+
 static unsigned long highmem_dirtyable_memory(unsigned long total)
 {
 #ifdef CONFIG_HIGHMEM
@@ -172,12 +173,12 @@ static unsigned long highmem_dirtyable_memory(unsigned long total)
 }
 
 /**
- * determine_dirtyable_memory - amount of memory that may be used
+ * global_dirtyable_memory - number of globally dirtyable pages
  *
- * Returns the numebr of pages that can currently be freed and used
- * by the kernel for direct mappings.
+ * Returns the global number of pages potentially available for dirty
+ * page cache.  This is the base value for the global dirty limits.
  */
-static unsigned long determine_dirtyable_memory(void)
+unsigned long global_dirtyable_memory(void)
 {
         unsigned long x;
 
@@ -191,6 +192,47 @@ static unsigned long determine_dirtyable_memory(void)
 }
 
 /*
+ * global_dirty_limits - background-writeback and dirty-throttling thresholds
+ *
+ * Calculate the dirty thresholds based on sysctl parameters
+ * - vm.dirty_background_ratio  or  vm.dirty_background_bytes
+ * - vm.dirty_ratio             or  vm.dirty_bytes
+ * The dirty limits will be lifted by 1/4 for PF_LESS_THROTTLE (ie. nfsd) and
+ * real-time tasks.
+ */
+void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty)
+{
+        unsigned long background;
+        unsigned long dirty;
+        unsigned long uninitialized_var(available_memory);
+        struct task_struct *tsk;
+
+        if (!vm_dirty_bytes || !dirty_background_bytes)
+                available_memory = global_dirtyable_memory();
+
+        if (vm_dirty_bytes)
+                dirty = DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE);
+        else
+                dirty = (vm_dirty_ratio * available_memory) / 100;
+
+        if (dirty_background_bytes)
+                background = DIV_ROUND_UP(dirty_background_bytes, PAGE_SIZE);
+        else
+                background = (dirty_background_ratio * available_memory) / 100;
+
+        if (background >= dirty)
+                background = dirty / 2;
+        tsk = current;
+        if (tsk->flags & PF_LESS_THROTTLE || rt_task(tsk)) {
+                background += background / 4;
+                dirty += dirty / 4;
+        }
+        *pbackground = background;
+        *pdirty = dirty;
+        trace_global_dirty_state(background, dirty);
+}
+
+/*
  * couple the period to the dirty_ratio:
  *
  *   period/2 ~ roundup_pow_of_two(dirty limit)
@@ -202,7 +244,7 @@ static int calc_period_shift(void)
         if (vm_dirty_bytes)
                 dirty_total = vm_dirty_bytes / PAGE_SIZE;
         else
-                dirty_total = (vm_dirty_ratio * determine_dirtyable_memory()) /
+                dirty_total = (vm_dirty_ratio * global_dirtyable_memory()) /
                                 100;
         return 2 + ilog2(dirty_total - 1);
 }
@@ -362,47 +404,6 @@ static unsigned long hard_dirty_limit(unsigned long thresh)
         return max(thresh, global_dirty_limit);
 }
 
-/*
- * global_dirty_limits - background-writeback and dirty-throttling thresholds
- *
- * Calculate the dirty thresholds based on sysctl parameters
- * - vm.dirty_background_ratio  or  vm.dirty_background_bytes
- * - vm.dirty_ratio             or  vm.dirty_bytes
- * The dirty limits will be lifted by 1/4 for PF_LESS_THROTTLE (ie. nfsd) and
- * real-time tasks.
- */
-void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty)
-{
-        unsigned long background;
-        unsigned long dirty;
-        unsigned long uninitialized_var(available_memory);
-        struct task_struct *tsk;
-
-        if (!vm_dirty_bytes || !dirty_background_bytes)
-                available_memory = determine_dirtyable_memory();
-
-        if (vm_dirty_bytes)
-                dirty = DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE);
-        else
-                dirty = (vm_dirty_ratio * available_memory) / 100;
-
-        if (dirty_background_bytes)
-                background = DIV_ROUND_UP(dirty_background_bytes, PAGE_SIZE);
-        else
-                background = (dirty_background_ratio * available_memory) / 100;
-
-        if (background >= dirty)
-                background = dirty / 2;
-        tsk = current;
-        if (tsk->flags & PF_LESS_THROTTLE || rt_task(tsk)) {
-                background += background / 4;
-                dirty += dirty / 4;
-        }
-        *pbackground = background;
-        *pdirty = dirty;
-        trace_global_dirty_state(background, dirty);
-}
-
 /**
  * bdi_dirty_limit - @bdi's share of dirty throttling threshold
  * @bdi: the backing_dev_info to query