On Sat 17-01-15 10:21:19, Johannes Weiner wrote:
> High limit reclaim can currently overscan in proportion to how many
> charges are happening concurrently. Tone it down such that charges
> don't target the entire high-boundary excess, but instead only the
> pages they charged themselves when excess is detected.
>
> Reported-by: Michal Hocko <mhocko@xxxxxxx>
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
I certainly agree with this approach.
Acked-by: Michal Hocko <mhocko@xxxxxxx>
Is this planned to be folded into the original patch or go on its own. I
am OK with both ways, maybe having it separate would be better from
documentation POV.
> ---
> mm/memcontrol.c | 16 +++++-----------
> 1 file changed, 5 insertions(+), 11 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 323a01fa1833..7adccee9fecb 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2348,19 +2348,13 @@ done_restock:
> refill_stock(memcg, batch - nr_pages);
> /*
> * If the hierarchy is above the normal consumption range,
> - * make the charging task trim the excess.
> + * make the charging task trim their excess contribution.
> */
> do {
> - unsigned long nr_pages = page_counter_read(&memcg->memory);
> - unsigned long high = ACCESS_ONCE(memcg->high);
> -
> - if (nr_pages > high) {
> - mem_cgroup_events(memcg, MEMCG_HIGH, 1);
> -
> - try_to_free_mem_cgroup_pages(memcg, nr_pages - high,
> - gfp_mask, true);
> - }
> -
> + if (page_counter_read(&memcg->memory) <= memcg->high)
> + continue;
> + mem_cgroup_events(memcg, MEMCG_HIGH, 1);
> + try_to_free_mem_cgroup_pages(memcg, nr_pages, gfp_mask, true);
> } while ((memcg = parent_mem_cgroup(memcg)));
> done:
> return ret;
> --
> 2.2.0
>
--
Michal Hocko
SUSE Labs
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