From: Muchun Song <songmuchun@bytedance.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>, Michal Hocko <mhocko@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Shakeel Butt <shakeelb@google.com>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>,
Xiongchun duan <duanxiongchun@bytedance.com>,
Hugh Dickins <hughd@google.com>
Subject: Re: [External] Re: [RFC PATCH 04/15] mm: memcontrol: use lruvec_memcg in lruvec_holds_page_lru_lock
Date: Sat, 3 Apr 2021 20:37:14 +0800 [thread overview]
Message-ID: <CAMZfGtWi7RCyqK4Ns1i4k2mVww8tJdV4LQfZUycRu2k_eXsp9g@mail.gmail.com> (raw)
In-Reply-To: <YGdEnN6WkKbNp1QJ@cmpxchg.org>
On Sat, Apr 3, 2021 at 12:21 AM Johannes Weiner <hannes@cmpxchg.org> wrote:
>
> On Tue, Mar 30, 2021 at 06:15:20PM +0800, Muchun Song wrote:
> > We already have a helper lruvec_memcg() to get the memcg from lruvec, we
> > do not need to do it ourselves in the lruvec_holds_page_lru_lock(). So use
> > lruvec_memcg() instead.
> >
> > Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> > ---
> > include/linux/memcontrol.h | 6 +++---
> > 1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> > index a35a22994cf7..6e3283828391 100644
> > --- a/include/linux/memcontrol.h
> > +++ b/include/linux/memcontrol.h
> > @@ -744,20 +744,20 @@ static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page)
> > return mem_cgroup_lruvec(memcg, pgdat);
> > }
> >
> > +static inline struct mem_cgroup *lruvec_memcg(struct lruvec *lruvec);
>
> Please reorder the functions instead to avoid forward decls.
OK. Will fix it in the next version.
>
> > static inline bool lruvec_holds_page_lru_lock(struct page *page,
> > struct lruvec *lruvec)
> > {
> > pg_data_t *pgdat = page_pgdat(page);
> > const struct mem_cgroup *memcg;
> > - struct mem_cgroup_per_node *mz;
> >
> > if (mem_cgroup_disabled())
> > return lruvec == &pgdat->__lruvec;
> >
> > - mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
> > memcg = page_memcg(page) ? : root_mem_cgroup;
> >
> > - return lruvec->pgdat == pgdat && mz->memcg == memcg;
> > + return lruvec->pgdat == pgdat && lruvec_memcg(lruvec) == memcg;
>
> Looks reasonable to me, but I wonder if there is more we can do.
>
> lruvec_memcg() already handles CONFIG_MEMCG and mem_cgroup_disabled()
> combinations, and there is also a lruvec_pgdat() which does.
>
> One thing that is odd is page_memcg(page) ? : root_mem_cgroup. How can
> lruvec pages not have a page_memcg()? mem_cgroup_page_lruvec() has:
You are right. page_memcg() cannot be NULL.
>
> memcg = page_memcg(page);
> VM_WARN_ON_ONCE_PAGE(!memcg && !mem_cgroup_disabled(), page);
>
> Unless I'm missing something, we should be able to have a single
> definition for this function that works for !CONFIG_MEMCG,
> CONFIG_MEMCG + mem_cgroup_disabled() and CONFIG_MEMCG:
>
> lruvec_holds_page_lru_lock()
> {
> return lruvec_pgdat(lruvec) == page_pgdat(page) &&
> lruvec_memcg(lruvec) == page_memcg(page);
> }
Aha, how wonderful! It is simpler than mine. I will use this.
Thanks for your suggestions.
next prev parent reply other threads:[~2021-04-03 12:37 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-30 10:15 [RFC PATCH 00/15] Use obj_cgroup APIs to charge the LRU pages Muchun Song
2021-03-30 10:15 ` [RFC PATCH 01/15] mm: memcontrol: fix page charging in page replacement Muchun Song
2021-04-02 15:07 ` Johannes Weiner
2021-03-30 10:15 ` [RFC PATCH 02/15] mm: memcontrol: bail out early when !mm in get_mem_cgroup_from_mm Muchun Song
2021-04-02 15:08 ` Johannes Weiner
2021-03-30 10:15 ` [RFC PATCH 03/15] mm: memcontrol: remove the pgdata parameter of mem_cgroup_page_lruvec Muchun Song
2021-04-02 15:22 ` Johannes Weiner
2021-03-30 10:15 ` [RFC PATCH 04/15] mm: memcontrol: use lruvec_memcg in lruvec_holds_page_lru_lock Muchun Song
2021-04-02 16:21 ` Johannes Weiner
2021-04-03 12:37 ` Muchun Song [this message]
2021-03-30 10:15 ` [RFC PATCH 05/15] mm: memcontrol: simplify the logic of objcg pinning memcg Muchun Song
2021-03-30 10:15 ` [RFC PATCH 06/15] mm: memcontrol: move the objcg infrastructure out of CONFIG_MEMCG_KMEM Muchun Song
2021-03-30 10:15 ` [RFC PATCH 07/15] mm: memcontrol: introduce compact_lock_page_lruvec_irqsave Muchun Song
2021-03-30 10:15 ` [RFC PATCH 08/15] mm: memcontrol: make lruvec lock safe when the LRU pages reparented Muchun Song
2021-03-30 10:15 ` [RFC PATCH 09/15] mm: thp: introduce lock/unlock_split_queue{_irqsave}() Muchun Song
2021-03-30 10:15 ` [RFC PATCH 10/15] mm: thp: make deferred split queue lock safe when the LRU pages reparented Muchun Song
2021-03-30 10:15 ` [RFC PATCH 11/15] mm: memcontrol: make all the callers of page_memcg() safe Muchun Song
2021-03-30 10:15 ` [RFC PATCH 12/15] mm: memcontrol: introduce memcg_reparent_ops Muchun Song
2021-03-30 10:15 ` [RFC PATCH 13/15] mm: memcontrol: use obj_cgroup APIs to charge the LRU pages Muchun Song
2021-03-30 10:15 ` [RFC PATCH 14/15] mm: memcontrol: rename {un}lock_page_memcg() to {un}lock_page_objcg() Muchun Song
2021-03-30 10:15 ` [RFC PATCH 15/15] mm: lru: add VM_BUG_ON_PAGE to lru maintenance function Muchun Song
2021-03-30 18:34 ` [RFC PATCH 00/15] Use obj_cgroup APIs to charge the LRU pages Shakeel Butt
2021-03-30 18:58 ` Roman Gushchin
2021-03-30 21:30 ` Johannes Weiner
2021-03-30 22:05 ` Roman Gushchin
2021-03-31 15:17 ` Johannes Weiner
2021-04-01 16:07 ` [External] " Muchun Song
2021-04-01 17:15 ` Shakeel Butt
2021-04-02 3:14 ` Muchun Song
2021-04-02 17:30 ` Johannes Weiner
2021-04-01 21:34 ` Roman Gushchin
2021-04-01 22:55 ` Yang Shi
2021-04-02 4:03 ` [External] " Muchun Song
2021-03-30 21:10 ` Johannes Weiner
2021-03-31 0:28 ` Shakeel Butt
2021-03-31 3:28 ` Balbir Singh
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAMZfGtWi7RCyqK4Ns1i4k2mVww8tJdV4LQfZUycRu2k_eXsp9g@mail.gmail.com \
--to=songmuchun@bytedance.com \
--cc=akpm@linux-foundation.org \
--cc=duanxiongchun@bytedance.com \
--cc=guro@fb.com \
--cc=hannes@cmpxchg.org \
--cc=hughd@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=shakeelb@google.com \
--cc=vdavydov.dev@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).