From: Johannes Weiner <jweiner@redhat.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andrew Morton <akpm@linux-foundation.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>,
Balbir Singh <bsingharora@gmail.com>,
Ying Han <yinghan@google.com>, Michal Hocko <mhocko@suse.cz>,
Greg Thelen <gthelen@google.com>,
Michel Lespinasse <walken@google.com>,
Rik van Riel <riel@redhat.com>,
Minchan Kim <minchan.kim@gmail.com>,
Christoph Hellwig <hch@infradead.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [patch 01/11] mm: memcg: consolidate hierarchy iteration primitives
Date: Tue, 13 Sep 2011 07:40:33 +0200 [thread overview]
Message-ID: <20110913054033.GC2929@redhat.com> (raw)
In-Reply-To: <20110912223746.GA20765@shutemov.name>
On Tue, Sep 13, 2011 at 01:37:46AM +0300, Kirill A. Shutemov wrote:
> On Mon, Sep 12, 2011 at 12:57:18PM +0200, Johannes Weiner wrote:
> > -static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter,
> > - struct mem_cgroup *root,
> > - bool cond)
> > -{
> > - int nextid = css_id(&iter->css) + 1;
> > - int found;
> > - int hierarchy_used;
> > - struct cgroup_subsys_state *css;
> > + if (prev && !remember)
> > + id = css_id(&prev->css);
> >
> > - hierarchy_used = iter->use_hierarchy;
> > + if (prev && prev != root)
> > + css_put(&prev->css);
> >
> > - css_put(&iter->css);
> > - /* If no ROOT, walk all, ignore hierarchy */
> > - if (!cond || (root && !hierarchy_used))
> > - return NULL;
> > + if (!root->use_hierarchy && root != root_mem_cgroup) {
> > + if (prev)
> > + return NULL;
> > + return root;
> > + }
> >
> > - if (!root)
> > - root = root_mem_cgroup;
> > + while (!mem) {
> > + struct cgroup_subsys_state *css;
> >
> > - do {
> > - iter = NULL;
> > - rcu_read_lock();
> > + if (remember)
> > + id = root->last_scanned_child;
> >
> > - css = css_get_next(&mem_cgroup_subsys, nextid,
> > - &root->css, &found);
> > - if (css && css_tryget(css))
> > - iter = container_of(css, struct mem_cgroup, css);
> > + rcu_read_lock();
> > + css = css_get_next(&mem_cgroup_subsys, id + 1, &root->css, &id);
> > + if (css) {
> > + if (css == &root->css || css_tryget(css))
>
> When does css != &root->css here?
It does not grab an extra reference to the passed hierarchy root, as
all callsites must already hold one to guarantee it's not going away.
> > +static void mem_cgroup_iter_break(struct mem_cgroup *root,
> > + struct mem_cgroup *prev)
> > +{
> > + if (!root)
> > + root = root_mem_cgroup;
> > + if (prev && prev != root)
> > + css_put(&prev->css);
> > +}
next prev parent reply other threads:[~2011-09-13 5:41 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-12 10:57 [patch 0/11] mm: memcg naturalization -rc3 Johannes Weiner
2011-09-12 10:57 ` [patch 01/11] mm: memcg: consolidate hierarchy iteration primitives Johannes Weiner
2011-09-12 22:37 ` Kirill A. Shutemov
2011-09-13 5:40 ` Johannes Weiner [this message]
2011-09-19 13:06 ` Michal Hocko
2011-09-13 10:06 ` KAMEZAWA Hiroyuki
2011-09-19 12:53 ` Michal Hocko
2011-09-20 8:45 ` Johannes Weiner
2011-09-20 8:53 ` Michal Hocko
2011-09-12 10:57 ` [patch 02/11] mm: vmscan: distinguish global reclaim from global LRU scanning Johannes Weiner
2011-09-12 23:02 ` Kirill A. Shutemov
2011-09-13 5:48 ` Johannes Weiner
2011-09-13 10:07 ` KAMEZAWA Hiroyuki
2011-09-19 13:23 ` Michal Hocko
2011-09-19 13:46 ` Michal Hocko
2011-09-20 8:52 ` Johannes Weiner
2011-09-12 10:57 ` [patch 03/11] mm: vmscan: distinguish between memcg triggering reclaim and memcg being scanned Johannes Weiner
2011-09-13 10:23 ` KAMEZAWA Hiroyuki
2011-09-19 14:29 ` Michal Hocko
2011-09-20 8:58 ` Johannes Weiner
2011-09-20 9:17 ` Michal Hocko
2011-09-29 7:55 ` Johannes Weiner
2011-09-12 10:57 ` [patch 04/11] mm: memcg: per-priority per-zone hierarchy scan generations Johannes Weiner
2011-09-13 10:27 ` KAMEZAWA Hiroyuki
2011-09-13 11:03 ` Johannes Weiner
2011-09-14 0:55 ` KAMEZAWA Hiroyuki
2011-09-14 5:56 ` Johannes Weiner
2011-09-14 7:40 ` KAMEZAWA Hiroyuki
2011-09-20 8:15 ` Michal Hocko
2011-09-20 8:45 ` Michal Hocko
2011-09-20 9:10 ` Johannes Weiner
2011-09-20 12:37 ` Michal Hocko
2011-09-12 10:57 ` [patch 05/11] mm: move memcg hierarchy reclaim to generic reclaim code Johannes Weiner
2011-09-13 10:31 ` KAMEZAWA Hiroyuki
2011-09-20 13:09 ` Michal Hocko
2011-09-20 13:29 ` Johannes Weiner
2011-09-20 14:08 ` Michal Hocko
2011-09-12 10:57 ` [patch 06/11] mm: memcg: remove optimization of keeping the root_mem_cgroup LRU lists empty Johannes Weiner
2011-09-13 10:34 ` KAMEZAWA Hiroyuki
2011-09-20 15:02 ` Michal Hocko
2011-09-29 9:20 ` Johannes Weiner
2011-09-29 9:49 ` Michal Hocko
2011-09-12 10:57 ` [patch 07/11] mm: vmscan: convert unevictable page rescue scanner to per-memcg LRU lists Johannes Weiner
2011-09-13 10:37 ` KAMEZAWA Hiroyuki
2011-09-21 12:33 ` Michal Hocko
2011-09-21 13:47 ` Johannes Weiner
2011-09-21 14:08 ` Michal Hocko
2011-09-12 10:57 ` [patch 08/11] mm: vmscan: convert global reclaim " Johannes Weiner
2011-09-13 10:41 ` KAMEZAWA Hiroyuki
2011-09-21 13:10 ` Michal Hocko
2011-09-21 13:51 ` Johannes Weiner
2011-09-21 13:57 ` Michal Hocko
2011-09-12 10:57 ` [patch 09/11] mm: collect LRU list heads into struct lruvec Johannes Weiner
2011-09-13 10:43 ` KAMEZAWA Hiroyuki
2011-09-21 13:43 ` Michal Hocko
2011-09-21 15:15 ` Michal Hocko
2011-09-12 10:57 ` [patch 10/11] mm: make per-memcg LRU lists exclusive Johannes Weiner
2011-09-13 10:47 ` KAMEZAWA Hiroyuki
2011-09-21 15:24 ` Michal Hocko
2011-09-21 15:47 ` Johannes Weiner
2011-09-21 16:05 ` Michal Hocko
2011-09-12 10:57 ` [patch 11/11] mm: memcg: remove unused node/section info from pc->flags Johannes Weiner
2011-09-13 10:50 ` KAMEZAWA Hiroyuki
2011-09-21 15:32 ` Michal Hocko
2011-09-13 20:35 ` [patch 0/11] mm: memcg naturalization -rc3 Kirill A. Shutemov
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