Re: [PATCH v3] memcg: refactor mem_cgroup_resize_limit()
From: Michal Hocko <hidden>
Date: 2017-06-13 11:35:53
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[Sorry for a late reponse] On Sun 04-06-17 14:18:07, Yu Zhao wrote:
mem_cgroup_resize_limit() and mem_cgroup_resize_memsw_limit() have identical logics. Refactor code so we don't need to keep two pieces of code that does same thing. Signed-off-by: Yu Zhao <redacted> Acked-by: Vladimir Davydov <redacted>
It is nice to see removal of the code duplication. I have one comment though [...]
quoted hunk ↗ jump to hunk
@@ -2498,22 +2449,24 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, } mutex_lock(&memcg_limit_mutex); - if (limit < memcg->memory.limit) { + inverted = memsw ? limit < memcg->memory.limit : + limit > memcg->memsw.limit; + if (inverted) { mutex_unlock(&memcg_limit_mutex); ret = -EINVAL; break; }
This is just too ugly and hard to understand. inverted just doesn't give
you a good clue what is going on. What do you think about something like
/*
* Make sure that the new limit (memsw or hard limit) doesn't
* break our basic invariant that memory.limit <= memsw.limit
*/
limits_invariant = memsw ? limit >= memcg->memory.limit :
limit <= mmecg->memsw.limit;
if (!limits_invariant) {
mutex_unlock(&memcg_limit_mutex);
ret = -EINVAL;
break;
}
with that feel free to add
Acked-by: Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>
--
Michal Hocko
SUSE Labs