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From: Johannes Weiner <hannes@cmpxchg.org>
To: Muchun Song <songmuchun@bytedance.com>
Cc: guro@fb.com, mhocko@kernel.org, akpm@linux-foundation.org,
	shakeelb@google.com, vdavydov.dev@gmail.com,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	duanxiongchun@bytedance.com
Subject: Re: [RFC PATCH 03/15] mm: memcontrol: remove the pgdata parameter of mem_cgroup_page_lruvec
Date: Fri, 2 Apr 2021 11:22:11 -0400	[thread overview]
Message-ID: <YGc2ozMAYph04nm2@cmpxchg.org> (raw)
In-Reply-To: <20210330101531.82752-4-songmuchun@bytedance.com>

On Tue, Mar 30, 2021 at 06:15:19PM +0800, Muchun Song wrote:
> All the callers of mem_cgroup_page_lruvec() just pass page_pgdat(page)
> as the 2nd parameter to it (except isolate_migratepages_block()). But
> for isolate_migratepages_block(), the page_pgdat(page) is also equal
> to the local variable of @pgdat. So mem_cgroup_page_lruvec() do not
> need the pgdat parameter. Just remove it to simplify the code.
> 
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>

There is a minor benefit in not doing the page_pgdat() lookup twice.
But I think it only really matters on 32-bit NUMA, where we have more
than one node but not enough space in page->flags to store the nid,
and so page_to_nid() is out-of-line and needs to go through section.

Those setups aren't really around anymore, and certainly don't justify
the hassle (and potential bugs) of the awkward interface.

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

  reply	other threads:[~2021-04-02 15:22 UTC|newest]

Thread overview: 44+ 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 [this message]
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     ` [External] " Muchun Song
2021-04-03 12:37       ` Muchun Song
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 18:34   ` 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 16:07             ` Muchun Song
2021-04-01 17:15             ` Shakeel Butt
2021-04-01 17:15               ` Shakeel Butt
2021-04-02  3:14               ` Muchun Song
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
2021-04-01 22:55             ` Yang Shi
2021-04-02  4:03             ` [External] " Muchun Song
2021-04-02  4:03               ` Muchun Song
2021-03-30 21:10   ` Johannes Weiner
2021-03-31  0:28     ` Shakeel Butt
2021-03-31  0:28       ` Shakeel Butt
2021-03-31  3:28     ` Balbir Singh

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