re: vmscan: shrinker->nr updates race and go wrong

[Dan Carpenter <error27@xxxxxxxxx>]

Hi Dave,

There is a sign error in e5b94d7463e0 "vmscan: shrinker->nr updates
race and go wrong"

mm/vmscan.c +274 shrink_slab(41)
	warn: unsigned 'total_scan' is never less than zero.

   268                  total_scan = nr;
   269                  max_pass = do_shrinker_shrink(shrinker, shrink, 0);
   270                  delta = (4 * nr_pages_scanned) / shrinker->seeks;
   271                  delta *= max_pass;
   272                  do_div(delta, lru_pages + 1);
   273                  total_scan += delta;
   274                  if (total_scan < 0) {
                            ^^^^^^^^^^^^^^
total_scan is unsigned so it's never less than zero here.

   275                          printk(KERN_ERR "shrink_slab: %pF negative objects to "
   276                                 "delete nr=%ld\n",
   277                                 shrinker->shrink, total_scan);
   278                          total_scan = max_pass;
   279                  }

regards,
dan carpenter

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