From: Michal Hocko <mhocko@suse.cz> To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, Johannes Weiner <hannes@cmpxchg.org>, Ying Han <yinghan@google.com>, Tejun Heo <htejun@gmail.com>, Glauber Costa <glommer@parallels.com>, Li Zefan <lizefan@huawei.com> Subject: [PATCH v3 6/7] memcg: further simplify mem_cgroup_iter Date: Thu, 3 Jan 2013 18:54:20 +0100 [thread overview] Message-ID: <1357235661-29564-7-git-send-email-mhocko@suse.cz> (raw) In-Reply-To: <1357235661-29564-1-git-send-email-mhocko@suse.cz> mem_cgroup_iter basically does two things currently. It takes care of the house keeping (reference counting, raclaim cookie) and it iterates through a hierarchy tree (by using cgroup generic tree walk). The code would be much more easier to follow if we move the iteration outside of the function (to __mem_cgrou_iter_next) so the distinction is more clear. This patch doesn't introduce any functional changes. Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> --- mm/memcontrol.c | 79 ++++++++++++++++++++++++++++++++----------------------- 1 file changed, 46 insertions(+), 33 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index d8c6e5e..d80fcff 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1110,6 +1110,51 @@ struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) return memcg; } +/* + * Returns a next (in a pre-order walk) alive memcg (with elevated css + * ref. count) or NULL if the whole root's subtree has been visited. + * + * helper function to be used by mem_cgroup_iter + */ +static struct mem_cgroup *__mem_cgroup_iter_next(struct mem_cgroup *root, + struct mem_cgroup *last_visited) +{ + struct cgroup *prev_cgroup, *next_cgroup; + + /* + * Root is not visited by cgroup iterators so it needs an + * explicit visit. + */ + if (!last_visited) + return root; + + prev_cgroup = (last_visited == root) ? NULL + : last_visited->css.cgroup; +skip_node: + next_cgroup = cgroup_next_descendant_pre( + prev_cgroup, root->css.cgroup); + + /* + * Even if we found a group we have to make sure it is + * alive. css && !memcg means that the groups should be + * skipped and we should continue the tree walk. + * last_visited css is safe to use because it is + * protected by css_get and the tree walk is rcu safe. + */ + if (next_cgroup) { + struct mem_cgroup *mem = mem_cgroup_from_cont( + next_cgroup); + if (css_tryget(&mem->css)) + return mem; + else { + prev_cgroup = next_cgroup; + goto skip_node; + } + } + + return NULL; +} + /** * mem_cgroup_iter - iterate over memory cgroup hierarchy * @root: hierarchy root @@ -1172,39 +1217,7 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, } } - /* - * Root is not visited by cgroup iterators so it needs an - * explicit visit. - */ - if (!last_visited) { - memcg = root; - } else { - struct cgroup *prev_cgroup, *next_cgroup; - - prev_cgroup = (last_visited == root) ? NULL - : last_visited->css.cgroup; -skip_node: - next_cgroup = cgroup_next_descendant_pre( - prev_cgroup, root->css.cgroup); - - /* - * Even if we found a group we have to make sure it is - * alive. css && !memcg means that the groups should be - * skipped and we should continue the tree walk. - * last_visited css is safe to use because it is - * protected by css_get and the tree walk is rcu safe. - */ - if (next_cgroup) { - struct mem_cgroup *mem = mem_cgroup_from_cont( - next_cgroup); - if (css_tryget(&mem->css)) - memcg = mem; - else { - prev_cgroup = next_cgroup; - goto skip_node; - } - } - } + memcg = __mem_cgroup_iter_next(root, last_visited); if (reclaim) { if (last_visited) -- 1.7.10.4
WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@suse.cz> To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, Johannes Weiner <hannes@cmpxchg.org>, Ying Han <yinghan@google.com>, Tejun Heo <htejun@gmail.com>, Glauber Costa <glommer@parallels.com>, Li Zefan <lizefan@huawei.com> Subject: [PATCH v3 6/7] memcg: further simplify mem_cgroup_iter Date: Thu, 3 Jan 2013 18:54:20 +0100 [thread overview] Message-ID: <1357235661-29564-7-git-send-email-mhocko@suse.cz> (raw) In-Reply-To: <1357235661-29564-1-git-send-email-mhocko@suse.cz> mem_cgroup_iter basically does two things currently. It takes care of the house keeping (reference counting, raclaim cookie) and it iterates through a hierarchy tree (by using cgroup generic tree walk). The code would be much more easier to follow if we move the iteration outside of the function (to __mem_cgrou_iter_next) so the distinction is more clear. This patch doesn't introduce any functional changes. Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> --- mm/memcontrol.c | 79 ++++++++++++++++++++++++++++++++----------------------- 1 file changed, 46 insertions(+), 33 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index d8c6e5e..d80fcff 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1110,6 +1110,51 @@ struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) return memcg; } +/* + * Returns a next (in a pre-order walk) alive memcg (with elevated css + * ref. count) or NULL if the whole root's subtree has been visited. + * + * helper function to be used by mem_cgroup_iter + */ +static struct mem_cgroup *__mem_cgroup_iter_next(struct mem_cgroup *root, + struct mem_cgroup *last_visited) +{ + struct cgroup *prev_cgroup, *next_cgroup; + + /* + * Root is not visited by cgroup iterators so it needs an + * explicit visit. + */ + if (!last_visited) + return root; + + prev_cgroup = (last_visited == root) ? NULL + : last_visited->css.cgroup; +skip_node: + next_cgroup = cgroup_next_descendant_pre( + prev_cgroup, root->css.cgroup); + + /* + * Even if we found a group we have to make sure it is + * alive. css && !memcg means that the groups should be + * skipped and we should continue the tree walk. + * last_visited css is safe to use because it is + * protected by css_get and the tree walk is rcu safe. + */ + if (next_cgroup) { + struct mem_cgroup *mem = mem_cgroup_from_cont( + next_cgroup); + if (css_tryget(&mem->css)) + return mem; + else { + prev_cgroup = next_cgroup; + goto skip_node; + } + } + + return NULL; +} + /** * mem_cgroup_iter - iterate over memory cgroup hierarchy * @root: hierarchy root @@ -1172,39 +1217,7 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, } } - /* - * Root is not visited by cgroup iterators so it needs an - * explicit visit. - */ - if (!last_visited) { - memcg = root; - } else { - struct cgroup *prev_cgroup, *next_cgroup; - - prev_cgroup = (last_visited == root) ? NULL - : last_visited->css.cgroup; -skip_node: - next_cgroup = cgroup_next_descendant_pre( - prev_cgroup, root->css.cgroup); - - /* - * Even if we found a group we have to make sure it is - * alive. css && !memcg means that the groups should be - * skipped and we should continue the tree walk. - * last_visited css is safe to use because it is - * protected by css_get and the tree walk is rcu safe. - */ - if (next_cgroup) { - struct mem_cgroup *mem = mem_cgroup_from_cont( - next_cgroup); - if (css_tryget(&mem->css)) - memcg = mem; - else { - prev_cgroup = next_cgroup; - goto skip_node; - } - } - } + memcg = __mem_cgroup_iter_next(root, last_visited); if (reclaim) { if (last_visited) -- 1.7.10.4 -- 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/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2013-01-03 17:56 UTC|newest] Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-01-03 17:54 [PATCH v3 0/7] rework mem_cgroup iterator Michal Hocko 2013-01-03 17:54 ` Michal Hocko 2013-01-03 17:54 ` [PATCH v3 1/7] memcg: synchronize per-zone iterator access by a spinlock Michal Hocko 2013-01-03 17:54 ` Michal Hocko 2013-01-03 17:54 ` [PATCH v3 2/7] memcg: keep prev's css alive for the whole mem_cgroup_iter Michal Hocko 2013-01-03 17:54 ` Michal Hocko 2013-01-03 17:54 ` [PATCH v3 3/7] memcg: rework mem_cgroup_iter to use cgroup iterators Michal Hocko 2013-01-03 17:54 ` Michal Hocko 2013-01-03 17:54 ` [PATCH v3 4/7] memcg: remove memcg from the reclaim iterators Michal Hocko 2013-01-03 17:54 ` Michal Hocko 2013-01-07 6:18 ` Kamezawa Hiroyuki 2013-01-07 6:18 ` Kamezawa Hiroyuki 2013-02-08 19:33 ` Johannes Weiner 2013-02-08 19:33 ` Johannes Weiner 2013-02-11 15:16 ` Michal Hocko 2013-02-11 15:16 ` Michal Hocko 2013-02-11 17:56 ` Johannes Weiner 2013-02-11 17:56 ` Johannes Weiner 2013-02-11 19:29 ` Michal Hocko 2013-02-11 19:29 ` Michal Hocko 2013-02-11 19:58 ` Johannes Weiner 2013-02-11 19:58 ` Johannes Weiner 2013-02-11 21:27 ` Michal Hocko 2013-02-11 21:27 ` Michal Hocko 2013-02-11 22:07 ` Michal Hocko 2013-02-11 22:07 ` Michal Hocko 2013-02-11 22:39 ` Johannes Weiner 2013-02-11 22:39 ` Johannes Weiner 2013-02-12 9:54 ` Michal Hocko 2013-02-12 9:54 ` Michal Hocko 2013-02-12 15:10 ` Johannes Weiner 2013-02-12 15:10 ` Johannes Weiner 2013-02-12 15:43 ` Michal Hocko 2013-02-12 15:43 ` Michal Hocko 2013-02-12 16:10 ` Paul E. McKenney 2013-02-12 16:10 ` Paul E. McKenney 2013-02-12 17:25 ` Johannes Weiner 2013-02-12 17:25 ` Johannes Weiner 2013-02-12 18:31 ` Paul E. McKenney 2013-02-12 18:31 ` Paul E. McKenney 2013-02-12 19:53 ` Johannes Weiner 2013-02-12 19:53 ` Johannes Weiner 2013-02-13 9:51 ` Michal Hocko 2013-02-13 9:51 ` Michal Hocko 2013-02-12 17:56 ` Michal Hocko 2013-02-12 17:56 ` Michal Hocko 2013-02-12 16:13 ` Michal Hocko 2013-02-12 16:13 ` Michal Hocko 2013-02-12 16:24 ` Michal Hocko 2013-02-12 16:24 ` Michal Hocko 2013-02-12 16:37 ` Michal Hocko 2013-02-12 16:37 ` Michal Hocko 2013-02-12 16:41 ` Johannes Weiner 2013-02-12 16:41 ` Johannes Weiner 2013-02-12 17:12 ` Michal Hocko 2013-02-12 17:12 ` Michal Hocko 2013-02-12 17:37 ` Johannes Weiner 2013-02-12 17:37 ` Johannes Weiner 2013-02-13 8:11 ` Glauber Costa 2013-02-13 8:11 ` Glauber Costa 2013-02-13 10:38 ` Michal Hocko 2013-02-13 10:38 ` Michal Hocko 2013-02-13 10:34 ` Michal Hocko 2013-02-13 10:34 ` Michal Hocko 2013-02-13 12:56 ` Michal Hocko 2013-02-13 12:56 ` Michal Hocko 2013-02-12 16:33 ` Johannes Weiner 2013-02-12 16:33 ` Johannes Weiner 2013-01-03 17:54 ` [PATCH v3 5/7] memcg: simplify mem_cgroup_iter Michal Hocko 2013-01-03 17:54 ` Michal Hocko 2013-01-03 17:54 ` Michal Hocko [this message] 2013-01-03 17:54 ` [PATCH v3 6/7] memcg: further " Michal Hocko 2013-01-03 17:54 ` [PATCH v3 7/7] cgroup: remove css_get_next Michal Hocko 2013-01-03 17:54 ` Michal Hocko 2013-01-04 3:42 ` Li Zefan 2013-01-04 3:42 ` Li Zefan 2013-01-23 12:52 ` [PATCH v3 0/7] rework mem_cgroup iterator Michal Hocko 2013-01-23 12:52 ` Michal Hocko
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