Re: [PATCH] Help Resource Counters Scale better (v4.1)

Daisuke Nishimura
2009-08-13T01:06:56Z

> @@ -1855,9 +1883,14 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
> break;
> }
>
> - res_counter_uncharge(&mem->res, PAGE_SIZE, &soft_limit_excess);
> - if (do_swap_account && (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
> - res_counter_uncharge(&mem->memsw, PAGE_SIZE, NULL);
> + if (!mem_cgroup_is_root(mem)) {
> + res_counter_uncharge(&mem->res, PAGE_SIZE, &soft_limit_excess);
> + if (do_swap_account &&
> + (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
> + res_counter_uncharge(&mem->memsw, PAGE_SIZE, NULL);
> + }
> + if (ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT && mem_cgroup_is_root(mem))
> + mem_cgroup_swap_statistics(mem, true);
I think mem_cgroup_is_root(mem) would be unnecessary here.
Otherwise, MEM_CGROUP_STAT_SWAPOUT of groups except root memcgroup wouldn't
be counted properly.

> @@ -2461,10 +2496,26 @@ static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
> name = MEMFILE_ATTR(cft->private);
> switch (type) {
> case _MEM:
> - val = res_counter_read_u64(&mem->res, name);
> + if (name == RES_USAGE && mem_cgroup_is_root(mem)) {
> + val = mem_cgroup_read_stat(&mem->stat,
> + MEM_CGROUP_STAT_CACHE);
> + val += mem_cgroup_read_stat(&mem->stat,
> + MEM_CGROUP_STAT_RSS);
> + val <<= PAGE_SHIFT;
> + } else
> + val = res_counter_read_u64(&mem->res, name);
> break;
> case _MEMSWAP:
> - val = res_counter_read_u64(&mem->memsw, name);
> + if (name == RES_USAGE && mem_cgroup_is_root(mem)) {
> + val = mem_cgroup_read_stat(&mem->stat,
> + MEM_CGROUP_STAT_CACHE);
> + val += mem_cgroup_read_stat(&mem->stat,
> + MEM_CGROUP_STAT_RSS);
> + val += mem_cgroup_read_stat(&mem->stat,
> + MEM_CGROUP_STAT_SWAPOUT);
> + val <<= PAGE_SHIFT;
> + } else
> + val = res_counter_read_u64(&mem->memsw, name);
> break;
> default:
> BUG();
Considering use_hierarchy==1 case in the root memcgroup, shouldn't we use
mem_cgroup_walk_tree() here to sum up all the children's usage ?
*.usage_in_bytes show sum of all the children's usage now if use_hierarchy==1.

Thanks,
Daisuke Nishimura.