Messages in this thread | | | Date | Wed, 30 Dec 2009 22:06:46 +0900 (JST) | From | KOSAKI Motohiro <> | Subject | Re: [PATCH 2/4] vmscan: get_scan_ratio cleanup |
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> * KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> [2009-12-28 16:48:06]: > > > The get_scan_ratio() should have all scan-ratio related calculations. > > Thus, this patch move some calculation into get_scan_ratio. > > > > Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> > > --- > > mm/vmscan.c | 23 ++++++++++++++--------- > > 1 files changed, 14 insertions(+), 9 deletions(-) > > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > index 2bbee91..640486b 100644 > > --- a/mm/vmscan.c > > +++ b/mm/vmscan.c > > @@ -1501,6 +1501,13 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc, > > unsigned long ap, fp; > > struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); > > > > + /* If we have no swap space, do not bother scanning anon pages. */ > > + if (!sc->may_swap || (nr_swap_pages <= 0)) { > > + percent[0] = 0; > > + percent[1] = 100; > > + return; > > + } > > + > > > > anon = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_ANON) + > > zone_nr_lru_pages(zone, sc, LRU_INACTIVE_ANON); > > file = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_FILE) + > > @@ -1598,22 +1605,20 @@ static void shrink_zone(int priority, struct zone *zone, > > unsigned long nr_reclaimed = sc->nr_reclaimed; > > unsigned long nr_to_reclaim = sc->nr_to_reclaim; > > struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); > > - int noswap = 0; > > > > - /* If we have no swap space, do not bother scanning anon pages. */ > > - if (!sc->may_swap || (nr_swap_pages <= 0)) { > > - noswap = 1; > > - percent[0] = 0; > > - percent[1] = 100; > > - } else > > - get_scan_ratio(zone, sc, percent); > > + get_scan_ratio(zone, sc, percent); > > Where do we set noswap? Is percent[0] == 0 used to indicate noswap = > 1?
Yes, I intended so. I guess your question can convert next sentence.
following case makes different result, is it intentional? - there are free swap - sc->may_swap == 1 - priority == 0 - percent[0] == 0
My answer is, it isn't happen on practical workload. if priority reach to 0, vmscan always scan and reclaim some anon (please recall, now vmscan automatically enable lumpy_reclaim if priority < 10), then recent_rotated_anon isn't 0 always.. practically.
Do you think this is wrong assumption?
> > for_each_evictable_lru(l) { > > int file = is_file_lru(l); > > unsigned long scan; > > > > + if (percent[file] == 0) { > > + nr[l] = 0; > > + continue; > > + } > > + > > Is this really needed? Won't nr_scan_try_batch handle it correctly?
this two if branch is nicer than "priority || noswap", I think. it clearly explain what do it.
> > > scan = zone_nr_lru_pages(zone, sc, l); > > - if (priority || noswap) { > > + if (priority) { > > scan >>= priority; > > scan = (scan * percent[file]) / 100; > > } > > -- > Balbir
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