Upgrade to 4.4.50-rt62

[kvmfornfv.git] / kernel / mm / page-writeback.c

diff --git a/kernel/mm/page-writeback.c b/kernel/mm/page-writeback.c
index d15d88c..fd51ebf 100644 (file)
--- 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;
        }