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-rw-r--r--mm/page-writeback.c93
1 files changed, 47 insertions, 46 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 9ab6de82d8e6..433fa990fe8b 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