UBUNTU: SAUCE: s390/mm: fix local TLB flushing vs. detach of an mm address space

[mirror_ubuntu-zesty-kernel.git] / mm / vmpressure.c

diff --git a/mm/vmpressure.c b/mm/vmpressure.c
index 149fdf6c5c56f927f3613538c61b3c5831c80af9..6063581f705c48b97a78a087d8c67127af9c8d68 100644 (file)
--- a/mm/vmpressure.c
+++ b/mm/vmpressure.c
@@ -112,8 +112,15 @@ static enum vmpressure_levels vmpressure_calc_level(unsigned long scanned,
                                                    unsigned long reclaimed)
 {
        unsigned long scale = scanned + reclaimed;
-       unsigned long pressure;
+       unsigned long pressure = 0;
 
+       /*
+        * reclaimed can be greater than scanned in cases
+        * like THP, where the scanned is 1 and reclaimed
+        * could be 512
+        */
+       if (reclaimed >= scanned)
+               goto out;
        /*
         * We calculate the ratio (in percents) of how many pages were
         * scanned vs. reclaimed in a given time frame (window). Note that
@@ -124,6 +131,7 @@ static enum vmpressure_levels vmpressure_calc_level(unsigned long scanned,
        pressure = scale - (reclaimed * scale / scanned);
        pressure = pressure * 100 / scale;
 
+out:
        pr_debug("%s: %3lu  (s: %lu  r: %lu)\n", __func__, pressure,
                 scanned, reclaimed);