Messages in this thread | | | Date | Fri, 11 Mar 2016 08:55:15 +0100 | From | Michal Hocko <> | Subject | Re: [PATCH] mm: memcontrol: reclaim when shrinking memory.high below usage |
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On Thu 10-03-16 15:50:13, Johannes Weiner wrote: > When setting memory.high below usage, nothing happens until the next > charge comes along, and then it will only reclaim its own charge and > not the now potentially huge excess of the new memory.high. This can > cause groups to stay in excess of their memory.high indefinitely. > > To fix that, when shrinking memory.high, kick off a reclaim cycle that > goes after the delta.
This has been the case since the knob was introduce but I wouldn't bother with the CC: stable # 4.0+ as this was still in experimental mode. I guess we want to have it in 4.5 or put it to 4.5 stable.
> > Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Thanks!
> --- > mm/memcontrol.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 8615b066b642..f7c9b4cbdf01 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -4992,6 +4992,7 @@ static ssize_t memory_high_write(struct kernfs_open_file *of, > char *buf, size_t nbytes, loff_t off) > { > struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); > + unsigned long nr_pages; > unsigned long high; > int err; > > @@ -5002,6 +5003,11 @@ static ssize_t memory_high_write(struct kernfs_open_file *of, > > memcg->high = high; > > + nr_pages = page_counter_read(&memcg->memory); > + if (nr_pages > high) > + try_to_free_mem_cgroup_pages(memcg, nr_pages - high, > + GFP_KERNEL, true); > + > memcg_wb_domain_size_changed(memcg); > return nbytes; > } > -- > 2.7.2
-- Michal Hocko SUSE Labs
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