Messages in this thread | | | Date | Thu, 07 Feb 2008 10:20:39 +0900 | From | KOSAKI Motohiro <> | Subject | Re: [patch 05/19] split LRU lists into anon & file sets |
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Hi Rik
Welcome back :)
> > I found number of scan pages calculation bug. > > My latest version of get_scan_ratio() works differently, with the > percentages always adding up to 100. However, your patch gave me > the inspiration to (hopefully) find the bug in my version of the > code.
OK.
> > 2. wrong fraction omission > > > > nr[l] = zone->nr_scan[l] * percent[file] / 100; > > > > when percent is very small, > > nr[l] become 0. > > This is probably where the problem is. Kind of. > > I believe that the problem is that we scale nr[l] by the percentage, > instead of scaling the amount we add to zone->nr_scan[l] by the > percentage!
Aahh, you are right.
> Index: linux-2.6.24-rc6-mm1/mm/vmscan.c > =================================================================== > --- linux-2.6.24-rc6-mm1.orig/mm/vmscan.c 2008-02-06 19:23:16.000000000 -0500 > +++ linux-2.6.24-rc6-mm1/mm/vmscan.c 2008-02-06 19:22:55.000000000 -0500 > @@ -1275,13 +1275,17 @@ static unsigned long shrink_zone(int pri > for_each_lru(l) { > if (scan_global_lru(sc)) { > int file = is_file_lru(l); > + int scan; > /* > * Add one to nr_to_scan just to make sure that the > - * kernel will slowly sift through the active list. > + * kernel will slowly sift through each list. > */ > - zone->nr_scan[l] += (zone_page_state(zone, > - NR_INACTIVE_ANON + l) >> priority) + 1; > - nr[l] = zone->nr_scan[l] * percent[file] / 100; > + scan = zone_page_state(zone, NR_INACTIVE_ANON + l); > + scan >>= priority; > + scan = (scan * percent[file]) / 100; > + > + zone->nr_scan[l] += scan + 1; > + nr[l] = zone->nr_scan[l]; > if (nr[l] >= sc->swap_cluster_max) > zone->nr_scan[l] = 0; > else
looks good. thank you clean up code.
- kosaki
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