From: Alex Shi <alex.shi@linux.alibaba.com>
To: Johannes Weiner <hannes@cmpxchg.org>, Joonsoo Kim <js1304@gmail.com>
Cc: Shakeel Butt <shakeelb@google.com>,
Hugh Dickins <hughd@google.com>, Michal Hocko <mhocko@suse.com>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Roman Gushchin <guro@fb.com>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH 18/18] mm: memcontrol: update page->mem_cgroup stability rules
Date: Tue, 21 Apr 2020 17:20:59 +0800 [thread overview]
Message-ID: <1f905391-5676-2db6-efb9-74ade130740e@linux.alibaba.com> (raw)
In-Reply-To: <20200420221126.341272-19-hannes@cmpxchg.org>
在 2020/4/21 上午6:11, Johannes Weiner 写道:
> The previous patches have simplified the access rules around
> page->mem_cgroup somewhat:
>
> 1. We never change page->mem_cgroup while the page is isolated by
> somebody else. This was by far the biggest exception to our rules
> and it didn't stop at lock_page() or lock_page_memcg().
>
> 2. We charge pages before they get put into page tables now, so the
> somewhat fishy rule about "can be in page table as long as it's
> still locked" is now gone and boiled down to having an exclusive
> reference to the page.
>
> Document the new rules. Any of the following will stabilize the
> page->mem_cgroup association:
>
> - the page lock
> - LRU isolation
> - lock_page_memcg()
> - exclusive access to the page
>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
> ---
> mm/memcontrol.c | 21 +++++++--------------
> 1 file changed, 7 insertions(+), 14 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index a8cce52b6b4d..7b63260c9b57 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1201,9 +1201,8 @@ int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
> * @page: the page
> * @pgdat: pgdat of the page
> *
> - * This function is only safe when following the LRU page isolation
> - * and putback protocol: the LRU lock must be held, and the page must
> - * either be PageLRU() or the caller must have isolated/allocated it.
> + * This function relies on page->mem_cgroup being stable - see the
> + * access rules in commit_charge().
> */
> struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgdat)
> {
> @@ -2605,18 +2604,12 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg)
> {
> VM_BUG_ON_PAGE(page->mem_cgroup, page);
> /*
> - * Nobody should be changing or seriously looking at
> - * page->mem_cgroup at this point:
> - *
> - * - the page is uncharged
> - *
> - * - the page is off-LRU
> - *
> - * - an anonymous fault has exclusive page access, except for
> - * a locked page table
> + * Any of the following ensures page->mem_cgroup stability:
> *
> - * - a page cache insertion, a swapin fault, or a migration
> - * have the page locked
> + * - the page lock
> + * - LRU isolation
> + * - lock_page_memcg()
> + * - exclusive reference
> */
> page->mem_cgroup = memcg;
> }
>
next prev parent reply other threads:[~2020-04-21 9:23 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-20 22:11 [PATCH 00/18] mm: memcontrol: charge swapin pages on instantiation Johannes Weiner
2020-04-20 22:11 ` [PATCH 01/18] mm: fix NUMA node file count error in replace_page_cache() Johannes Weiner
2020-04-21 8:28 ` Alex Shi
2020-04-21 19:13 ` Shakeel Butt
2020-04-22 6:34 ` Joonsoo Kim
2020-04-20 22:11 ` [PATCH 02/18] mm: memcontrol: fix theoretical race in charge moving Johannes Weiner
2020-04-22 6:36 ` Joonsoo Kim
2020-04-22 16:51 ` Shakeel Butt
2020-04-22 17:42 ` Johannes Weiner
2020-04-22 18:01 ` Shakeel Butt
2020-04-22 18:02 ` Shakeel Butt
2020-04-20 22:11 ` [PATCH 03/18] mm: memcontrol: drop @compound parameter from memcg charging API Johannes Weiner
2020-04-21 9:11 ` Alex Shi
2020-04-22 6:37 ` Joonsoo Kim
2020-04-22 17:30 ` Shakeel Butt
2020-04-20 22:11 ` [PATCH 04/18] mm: memcontrol: move out cgroup swaprate throttling Johannes Weiner
2020-04-21 9:11 ` Alex Shi
2020-04-22 6:37 ` Joonsoo Kim
2020-04-22 22:20 ` Shakeel Butt
2020-04-20 22:11 ` [PATCH 05/18] mm: memcontrol: convert page cache to a new mem_cgroup_charge() API Johannes Weiner
2020-04-21 9:12 ` Alex Shi
2020-04-22 6:40 ` Joonsoo Kim
2020-04-22 12:09 ` Johannes Weiner
2020-04-23 5:25 ` Joonsoo Kim
2020-05-08 16:01 ` Johannes Weiner
2020-05-11 1:57 ` Joonsoo Kim
2020-05-11 7:38 ` Hugh Dickins
2020-05-11 15:06 ` Johannes Weiner
2020-05-11 16:32 ` Hugh Dickins
2020-05-11 18:10 ` Johannes Weiner
2020-05-11 18:12 ` Johannes Weiner
2020-05-11 18:44 ` Hugh Dickins
2020-04-20 22:11 ` [PATCH 06/18] mm: memcontrol: prepare uncharging for removal of private page type counters Johannes Weiner
2020-04-21 9:12 ` Alex Shi
2020-04-22 6:41 ` Joonsoo Kim
2020-04-20 22:11 ` [PATCH 07/18] mm: memcontrol: prepare move_account " Johannes Weiner
2020-04-21 9:13 ` Alex Shi
2020-04-22 6:41 ` Joonsoo Kim
2020-04-20 22:11 ` [PATCH 08/18] mm: memcontrol: prepare cgroup vmstat infrastructure for native anon counters Johannes Weiner
2020-04-22 6:42 ` Joonsoo Kim
2020-04-20 22:11 ` [PATCH 09/18] mm: memcontrol: switch to native NR_FILE_PAGES and NR_SHMEM counters Johannes Weiner
2020-04-22 6:42 ` Joonsoo Kim
2020-04-20 22:11 ` [PATCH 10/18] mm: memcontrol: switch to native NR_ANON_MAPPED counter Johannes Weiner
2020-04-22 6:51 ` Joonsoo Kim
2020-04-22 12:28 ` Johannes Weiner
2020-04-23 5:27 ` Joonsoo Kim
2020-04-20 22:11 ` [PATCH 11/18] mm: memcontrol: switch to native NR_ANON_THPS counter Johannes Weiner
2020-04-24 0:29 ` Joonsoo Kim
2020-04-20 22:11 ` [PATCH 12/18] mm: memcontrol: convert anon and file-thp to new mem_cgroup_charge() API Johannes Weiner
2020-04-24 0:29 ` Joonsoo Kim
2020-04-20 22:11 ` [PATCH 13/18] mm: memcontrol: drop unused try/commit/cancel charge API Johannes Weiner
2020-04-24 0:30 ` Joonsoo Kim
2020-04-20 22:11 ` [PATCH 14/18] mm: memcontrol: prepare swap controller setup for integration Johannes Weiner
2020-04-24 0:30 ` Joonsoo Kim
2020-04-20 22:11 ` [PATCH 15/18] mm: memcontrol: make swap tracking an integral part of memory control Johannes Weiner
2020-04-21 9:27 ` Alex Shi
2020-04-21 14:39 ` Johannes Weiner
2020-04-22 3:14 ` Alex Shi
2020-04-22 13:30 ` Johannes Weiner
2020-04-22 13:40 ` Alex Shi
2020-04-22 13:43 ` Alex Shi
2020-04-24 0:30 ` Joonsoo Kim
2020-04-24 3:01 ` Johannes Weiner
2020-04-20 22:11 ` [PATCH 16/18] mm: memcontrol: charge swapin pages on instantiation Johannes Weiner
2020-04-21 9:21 ` Alex Shi
2020-04-24 0:44 ` Joonsoo Kim
2020-04-24 2:51 ` Johannes Weiner
2020-04-28 6:49 ` Joonsoo Kim
2020-04-20 22:11 ` [PATCH 17/18] mm: memcontrol: delete unused lrucare handling Johannes Weiner
2020-04-24 0:46 ` Joonsoo Kim
2020-04-20 22:11 ` [PATCH 18/18] mm: memcontrol: update page->mem_cgroup stability rules Johannes Weiner
2020-04-21 9:20 ` Alex Shi [this message]
2020-04-24 0:48 ` Joonsoo Kim
2020-04-21 9:10 ` Hillf Danton
2020-04-21 14:34 ` Johannes Weiner
2020-04-21 9:32 ` [PATCH 00/18] mm: memcontrol: charge swapin pages on instantiation Alex Shi
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=1f905391-5676-2db6-efb9-74ade130740e@linux.alibaba.com \
--to=alex.shi@linux.alibaba.com \
--cc=cgroups@vger.kernel.org \
--cc=guro@fb.com \
--cc=hannes@cmpxchg.org \
--cc=hughd@google.com \
--cc=js1304@gmail.com \
--cc=kernel-team@fb.com \
--cc=kirill@shutemov.name \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--cc=shakeelb@google.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).