Re: [PATCH v3 02/21] memcg: make mm_match_cgroup() hirarchical
From: Johannes Weiner <hannes@cmpxchg.org>
Date: 2012-02-23 18:04:04
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On Thu, Feb 23, 2012 at 05:51:46PM +0400, Konstantin Khlebnikov wrote:
Check mm-owner cgroup membership hierarchically.
I think this one cat just beat up this other cat in front of my window, yelling something about money and missing product. Anyway, I already forgot why we want this patch. Could you describe that in the changelog, please?
quoted hunk ↗ jump to hunk
@@ -821,6 +821,26 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) struct mem_cgroup, css); } +/** + * mm_match_cgroup - cgroup hierarchy mm membership test + * @mm mm_struct to test + * @cgroup target cgroup + * + * Returns true if mm belong this cgroup or any its child in hierarchy + */ +int mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *cgroup) +{ + struct mem_cgroup *memcg; + + rcu_read_lock(); + memcg = mem_cgroup_from_task(rcu_dereference((mm)->owner)); + while (memcg != cgroup && memcg && memcg->use_hierarchy) + memcg = parent_mem_cgroup(memcg); + rcu_read_unlock(); + + return cgroup == memcg; +}
Please don't duplicate mem_cgroup_same_or_subtree()'s functionality in a worse way. The hierarchy information is kept in a stack such that ancestry can be detected in linear time, check out css_is_ancestor(). If you don't want to nest rcu_read_lock(), you could push the rcu_read_lock() from css_is_ancestor() into its sole user and provide a __mem_cgroup_is_ancestor() that assumes rcu already read-locked. No? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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@kvack.org"> email@kvack.org </a>