summaryrefslogtreecommitdiffstats
path: root/kernel/mm/page-writeback.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/mm/page-writeback.c')
-rw-r--r--kernel/mm/page-writeback.c27
1 files changed, 16 insertions, 11 deletions
diff --git a/kernel/mm/page-writeback.c b/kernel/mm/page-writeback.c
index d15d88c8e..fd51ebfc4 100644
--- a/kernel/mm/page-writeback.c
+++ b/kernel/mm/page-writeback.c
@@ -359,8 +359,9 @@ 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;
@@ -372,26 +373,28 @@ 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;
@@ -1899,7 +1902,8 @@ bool wb_over_bg_thresh(struct bdi_writeback *wb)
if (gdtc->dirty > gdtc->bg_thresh)
return true;
- if (wb_stat(wb, WB_RECLAIMABLE) > __wb_calc_thresh(gdtc))
+ if (wb_stat(wb, WB_RECLAIMABLE) >
+ wb_calc_thresh(gdtc->wb, gdtc->bg_thresh))
return true;
if (mdtc) {
@@ -1913,7 +1917,8 @@ bool wb_over_bg_thresh(struct bdi_writeback *wb)
if (mdtc->dirty > mdtc->bg_thresh)
return true;
- if (wb_stat(wb, WB_RECLAIMABLE) > __wb_calc_thresh(mdtc))
+ if (wb_stat(wb, WB_RECLAIMABLE) >
+ wb_calc_thresh(mdtc->wb, mdtc->bg_thresh))
return true;
}