On Mon 26-03-12 17:18:15, Johannes Weiner wrote: > On Mon, Mar 26, 2012 at 05:04:29PM +0200, Michal Hocko wrote: > > [Adding Johannes to CC] > > > > On Fri 23-03-12 01:56:16, Konstantin Khlebnikov wrote: > > > From: Hugh Dickins <hughd@xxxxxxxxxx> > > > > > > Although one has to admire the skill with which it has been concealed, > > > scanning_global_lru(mz) is actually just an interesting way to test > > > mem_cgroup_disabled(). Too many developer hours have been wasted on > > > confusing it with global_reclaim(): just use mem_cgroup_disabled(). > > > > Is this really correct? > > Yes, if the memory controller is enabled, we never have a global LRU > and always scan the per-memcg lists. > > > > Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx> > > > Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx> > > > Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > > > Acked-by: Glauber Costa <glommer@xxxxxxxxxxxxx> > > > --- > > > mm/vmscan.c | 18 ++++-------------- > > > 1 files changed, 4 insertions(+), 14 deletions(-) > > > > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > > index 49f15ef..c684f44 100644 > > > --- a/mm/vmscan.c > > > +++ b/mm/vmscan.c > > [...] > > > @@ -1806,7 +1796,7 @@ static int inactive_anon_is_low(struct mem_cgroup_zone *mz) > > > if (!total_swap_pages) > > > return 0; > > > > > > - if (!scanning_global_lru(mz)) > > > + if (!mem_cgroup_disabled()) > > > return mem_cgroup_inactive_anon_is_low(mz->mem_cgroup, > > > mz->zone); > > > > mem_cgroup_inactive_anon_is_low calculation is slightly different than > > what we have for cgroup_disabled case. calculate_zone_inactive_ratio > > considers _all_ present pages in the zone while memcg variant only > > active+inactive. > > The memcg has nothing to go by but actual number of LRU pages; there > is no 'present pages' equivalent. Yes > I don't think that it matters much in reality given the sqrt scale, > but the difference is still unfortunate. OK you are probably right that the scale is too small to be a problem. I guess that a note about changed ratio calculation should be added to the changelog. > Konstantin was meaning to unify all this, though. > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@xxxxxxxxx. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>