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authorIngo Molnar <mingo@kernel.org>2016-06-14 11:04:13 +0200
committerIngo Molnar <mingo@kernel.org>2016-06-14 11:04:13 +0200
commit07f9f22087a94e8162f77ee997c52a23f158aee8 (patch)
tree04bfe0395c6aa95bae5c6983c3433d9ac8eb7731 /mm/page-writeback.c
parent03c041c5bf6ed584dff36b7cd509e0146a124277 (diff)
parentb7fa30c9cc48c4f55663420472505d3b4f6e1705 (diff)
Merge branch 'sched/urgent' into sched/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'mm/page-writeback.c')
-rw-r--r--mm/page-writeback.c21
1 files changed, 12 insertions, 9 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index b9956fdee8f5..e2481949494c 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -373,8 +373,9 @@ static void domain_dirty_limits(struct dirty_throttle_control *dtc)
struct dirty_throttle_control *gdtc = mdtc_gdtc(dtc);
unsigned long bytes = vm_dirty_bytes;
unsigned long bg_bytes = dirty_background_bytes;
- unsigned long ratio = vm_dirty_ratio;
- unsigned long bg_ratio = dirty_background_ratio;
+ /* convert ratios to per-PAGE_SIZE for higher precision */
+ unsigned long ratio = (vm_dirty_ratio * PAGE_SIZE) / 100;
+ unsigned long bg_ratio = (dirty_background_ratio * PAGE_SIZE) / 100;
unsigned long thresh;
unsigned long bg_thresh;
struct task_struct *tsk;
@@ -386,26 +387,28 @@ static void domain_dirty_limits(struct dirty_throttle_control *dtc)
/*
* The byte settings can't be applied directly to memcg
* domains. Convert them to ratios by scaling against
- * globally available memory.
+ * globally available memory. As the ratios are in
+ * per-PAGE_SIZE, they can be obtained by dividing bytes by
+ * number of pages.
*/
if (bytes)
- ratio = min(DIV_ROUND_UP(bytes, PAGE_SIZE) * 100 /
- global_avail, 100UL);
+ ratio = min(DIV_ROUND_UP(bytes, global_avail),
+ PAGE_SIZE);
if (bg_bytes)
- bg_ratio = min(DIV_ROUND_UP(bg_bytes, PAGE_SIZE) * 100 /
- global_avail, 100UL);
+ bg_ratio = min(DIV_ROUND_UP(bg_bytes, global_avail),
+ PAGE_SIZE);
bytes = bg_bytes = 0;
}
if (bytes)
thresh = DIV_ROUND_UP(bytes, PAGE_SIZE);
else
- thresh = (ratio * available_memory) / 100;
+ thresh = (ratio * available_memory) / PAGE_SIZE;
if (bg_bytes)
bg_thresh = DIV_ROUND_UP(bg_bytes, PAGE_SIZE);
else
- bg_thresh = (bg_ratio * available_memory) / 100;
+ bg_thresh = (bg_ratio * available_memory) / PAGE_SIZE;
if (bg_thresh >= thresh)
bg_thresh = thresh / 2;