From: Alexander Duyck <alexander.duyck@gmail.com>
To: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>,
kbuild test robot <lkp@intel.com>,
Rong Chen <rong.a.chen@intel.com>,
Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Hugh Dickins <hughd@google.com>,
LKML <linux-kernel@vger.kernel.org>,
Daniel Jordan <daniel.m.jordan@oracle.com>,
linux-mm <linux-mm@kvack.org>,
Shakeel Butt <shakeelb@google.com>,
Matthew Wilcox <willy@infradead.org>,
Johannes Weiner <hannes@cmpxchg.org>, Tejun Heo <tj@kernel.org>,
cgroups@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Wei Yang <richard.weiyang@gmail.com>,
Mel Gorman <mgorman@techsingularity.net>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: Re: [RFC PATCH v2 5/5] mm: Split move_pages_to_lru into 3 separate passes
Date: Thu, 20 Aug 2020 10:15:17 -0700 [thread overview]
Message-ID: <CAKgT0Ueibb_MBvq4CeOO2ZkQfigv5SOC4=13Bfdzdj_9zt4O7Q@mail.gmail.com> (raw)
In-Reply-To: <87ded438-e908-117d-ecfb-1af7224d46da@linux.alibaba.com>
On Thu, Aug 20, 2020 at 2:58 AM Alex Shi <alex.shi@linux.alibaba.com> wrote:
>
>
>
> 在 2020/8/19 下午10:42, Alexander Duyck 写道:
> >> It's actually changed the meaning from current func. which I had seen a bug if no relock.
> >> but after move to 5.9 kernel, I can not reprodce the bug any more. I am not sure if 5.9 fixed
> >> the problem, and we don't need relock here.
> > So I am not sure what you mean here about "changed the meaning from
> > the current func". Which function are you referring to and what
> > changed?
> >
> > From what I can tell the pages cannot change memcg because they were
> > isolated and had the LRU flag stripped. They shouldn't be able to
> > change destination LRU vector as a result. Assuming that, then they
> > can all be processed under same LRU lock and we can avoid having to
> > release it until we are forced to do so to call putback_lru_page or
> > destroy the compound pages that were freed while we were shrinking the
> > LRU lists.
> >
>
> I had sent a bug which base on 5.8 kernel.
> https://lkml.org/lkml/2020/7/28/465
>
> I am not sure it was fixed in new kernel. The original line was introduced by Hugh Dickins
> I believe it would be great if you can get comments from him.
When I brought this up before you had pointed to the relocking being
due to the fact that the function was reacquiring the lruvec for some
reason. I wonder if the fact that the LRU bit stripping serializing
things made it so that the check for the lruvec after releasing the
lock became redundant.
- Alex
prev parent reply other threads:[~2020-08-20 17:15 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-19 4:26 [RFC PATCH v2 0/5] Minor cleanups and performance optimizations for LRU rework Alexander Duyck
2020-08-19 4:27 ` [RFC PATCH v2 1/5] mm: Identify compound pages sooner in isolate_migratepages_block Alexander Duyck
2020-08-19 7:48 ` Alex Shi
2020-08-19 11:43 ` Matthew Wilcox
2020-08-19 14:48 ` Alexander Duyck
2020-08-19 4:27 ` [RFC PATCH v2 2/5] mm: Drop use of test_and_set_skip in favor of just setting skip Alexander Duyck
2020-08-19 7:50 ` Alex Shi
2020-08-19 4:27 ` [RFC PATCH v2 3/5] mm: Add explicit page decrement in exception path for isolate_lru_pages Alexander Duyck
2020-08-19 7:50 ` Alex Shi
2020-08-19 14:52 ` Alexander Duyck
2020-08-19 4:27 ` [RFC PATCH v2 4/5] mm: Split release_pages work into 3 passes Alexander Duyck
2020-08-19 7:53 ` Alex Shi
2020-08-19 14:57 ` Alexander Duyck
2020-08-20 9:49 ` Alex Shi
2020-08-20 14:13 ` Alexander Duyck
2020-08-19 4:27 ` [RFC PATCH v2 5/5] mm: Split move_pages_to_lru into 3 separate passes Alexander Duyck
2020-08-19 7:56 ` Alex Shi
2020-08-19 14:42 ` Alexander Duyck
2020-08-20 9:56 ` Alex Shi
2020-08-20 17:15 ` Alexander Duyck [this message]
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='CAKgT0Ueibb_MBvq4CeOO2ZkQfigv5SOC4=13Bfdzdj_9zt4O7Q@mail.gmail.com' \
--to=alexander.duyck@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=alex.shi@linux.alibaba.com \
--cc=cgroups@vger.kernel.org \
--cc=daniel.m.jordan@oracle.com \
--cc=hannes@cmpxchg.org \
--cc=hughd@google.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=khlebnikov@yandex-team.ru \
--cc=kirill@shutemov.name \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lkp@intel.com \
--cc=mgorman@techsingularity.net \
--cc=richard.weiyang@gmail.com \
--cc=rong.a.chen@intel.com \
--cc=shakeelb@google.com \
--cc=tj@kernel.org \
--cc=willy@infradead.org \
--cc=yang.shi@linux.alibaba.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).