From: Michal Hocko <mhocko@suse.com>
To: Muchun Song <songmuchun@bytedance.com>
Cc: guro@fb.com, hannes@cmpxchg.org, akpm@linux-foundation.org,
shakeelb@google.com, vdavydov.dev@gmail.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
duanxiongchun@bytedance.com, fam.zheng@bytedance.com
Subject: Re: [PATCH 4/7] mm: memcontrol: simplify lruvec_holds_page_lru_lock
Date: Wed, 14 Apr 2021 11:44:10 +0200 [thread overview]
Message-ID: <YHa5ao/JgoqHQh0Z@dhcp22.suse.cz> (raw)
In-Reply-To: <20210413065153.63431-5-songmuchun@bytedance.com>
On Tue 13-04-21 14:51:50, 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. And if mem_cgroup_disabled() returns false, the
> page_memcg(page) (the LRU pages) cannot be NULL. So remove the odd logic
> of "memcg = page_memcg(page) ? : root_mem_cgroup". And use lruvec_pgdat
> to simplify the code. We can have a single definition for this function
> that works for !CONFIG_MEMCG, CONFIG_MEMCG + mem_cgroup_disabled() and
> CONFIG_MEMCG.
Neat. While you are at it wouldn't it make sesne to rename the function
as well. I do not want to bikeshed but this is really a misnomer. it
doesn't check anything about locking. page_belongs_lruvec?
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> include/linux/memcontrol.h | 31 +++++++------------------------
> 1 file changed, 7 insertions(+), 24 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 4f49865c9958..38b8d3fb24ff 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -755,22 +755,6 @@ static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page)
> return mem_cgroup_lruvec(memcg, pgdat);
> }
>
> -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;
> -}
> -
> struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
>
> struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm);
> @@ -1229,14 +1213,6 @@ static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page)
> return &pgdat->__lruvec;
> }
>
> -static inline bool lruvec_holds_page_lru_lock(struct page *page,
> - struct lruvec *lruvec)
> -{
> - pg_data_t *pgdat = page_pgdat(page);
> -
> - return lruvec == &pgdat->__lruvec;
> -}
> -
> static inline void lruvec_memcg_debug(struct lruvec *lruvec, struct page *page)
> {
> }
> @@ -1518,6 +1494,13 @@ static inline void unlock_page_lruvec_irqrestore(struct lruvec *lruvec,
> spin_unlock_irqrestore(&lruvec->lru_lock, flags);
> }
>
> +static inline bool lruvec_holds_page_lru_lock(struct page *page,
> + struct lruvec *lruvec)
> +{
> + return lruvec_pgdat(lruvec) == page_pgdat(page) &&
> + lruvec_memcg(lruvec) == page_memcg(page);
> +}
> +
> /* Don't lock again iff page's lruvec locked */
> static inline struct lruvec *relock_page_lruvec_irq(struct page *page,
> struct lruvec *locked_lruvec)
> --
> 2.11.0
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2021-04-14 9:44 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-13 6:51 [PATCH 0/7] memcontrol code cleanup and simplification Muchun Song
2021-04-13 6:51 ` [PATCH 1/7] mm: memcontrol: fix page charging in page replacement Muchun Song
2021-04-13 17:45 ` Roman Gushchin
2021-04-14 9:20 ` Michal Hocko
2021-04-13 6:51 ` [PATCH 2/7] mm: memcontrol: bail out early when !mm in get_mem_cgroup_from_mm Muchun Song
2021-04-13 17:47 ` Roman Gushchin
2021-04-14 9:24 ` Michal Hocko
2021-04-14 10:04 ` [External] " Muchun Song
2021-04-14 10:15 ` Michal Hocko
2021-04-15 3:13 ` Muchun Song
2021-04-15 7:09 ` Michal Hocko
2021-04-13 6:51 ` [PATCH 3/7] mm: memcontrol: remove the pgdata parameter of mem_cgroup_page_lruvec Muchun Song
2021-04-13 13:12 ` Shakeel Butt
2021-04-13 17:48 ` Roman Gushchin
2021-04-14 9:27 ` Michal Hocko
2021-04-13 6:51 ` [PATCH 4/7] mm: memcontrol: simplify lruvec_holds_page_lru_lock Muchun Song
2021-04-13 13:28 ` Shakeel Butt
2021-04-13 17:57 ` Roman Gushchin
2021-04-14 9:44 ` Michal Hocko [this message]
2021-04-14 10:00 ` [External] " Muchun Song
2021-04-14 17:49 ` Johannes Weiner
2021-04-15 7:08 ` Michal Hocko
2021-04-15 10:01 ` Muchun Song
2021-04-13 6:51 ` [PATCH 5/7] mm: memcontrol: simplify the logic of objcg pinning memcg Muchun Song
2021-04-13 14:16 ` Shakeel Butt
2021-04-13 17:51 ` Roman Gushchin
2021-04-13 6:51 ` [PATCH 6/7] mm: memcontrol: move obj_cgroup_uncharge_pages() out of css_set_lock Muchun Song
2021-04-13 14:18 ` Shakeel Butt
2021-04-13 17:54 ` Roman Gushchin
2021-04-13 18:03 ` Johannes Weiner
2021-04-13 6:51 ` [PATCH 7/7] mm: vmscan: remove noinline_for_stack Muchun Song
2021-04-14 9:46 ` Michal Hocko
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