From: SeongJae Park <sj@kernel.org>
To: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: SeongJae Park <sj@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
damon@lists.linux.dev
Subject: Re: [PATCH v2 2/3] mm/damon/paddr: minor refactor of damon_pa_young()
Date: Tue, 7 Mar 2023 18:00:23 +0000 [thread overview]
Message-ID: <20230307180023.152415-1-sj@kernel.org> (raw)
In-Reply-To: <174e75a4-f03c-a542-5f6a-651abb5dec58@huawei.com>
On Tue, 7 Mar 2023 09:22:33 +0800 Kefeng Wang <wangkefeng.wang@huawei.com> wrote:
>
>
> On 2023/3/7 5:27, SeongJae Park wrote:
> > Hi Kefeng,
> >
> > On Mon, 6 Mar 2023 09:56:49 +0800 Kefeng Wang <wangkefeng.wang@huawei.com> wrote:
> >
> >>
> >>
> >> On 2023/3/6 9:10, Kefeng Wang wrote:
> >>>
> >>>
> >>> On 2023/3/4 2:39, SeongJae Park wrote:
> >>>> Hi Kefeng,
> >>>>
> >>>> On Fri, 3 Mar 2023 16:43:42 +0800 Kefeng Wang
> >>>> <wangkefeng.wang@huawei.com> wrote:
> >>>>
> >>>>> Omit three lines by unified folio_put(), and make code more clear.
> >>>>>
> >>>>> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> >>>>> ---
> >>>>> mm/damon/paddr.c | 11 ++++-------
> >>>>> 1 file changed, 4 insertions(+), 7 deletions(-)
> >>>>>
> >>>>> diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
> >>>>> index 3fda00a0f786..2ef9db0189ca 100644
> >>>>> --- a/mm/damon/paddr.c
> >>>>> +++ b/mm/damon/paddr.c
> >>>>> @@ -130,24 +130,21 @@ static bool damon_pa_young(unsigned long paddr,
> >>>>> unsigned long *folio_sz)
> >>>>> accessed = false;
> >>>>> else
> >>>>> accessed = true;
> >>>>> - folio_put(folio);
> >>>>> goto out;
> >>>>
> >>>> Because you moved 'out' label to not include *folio_sz setting,
> >>>> folio_sz will
> >>>> not set in this case. It should be set.
> >>> oh, it should be fixed.
> >>>>
> >>>>> }
> >>>>> need_lock = !folio_test_anon(folio) || folio_test_ksm(folio);
> >>>>> - if (need_lock && !folio_trylock(folio)) {
> >>>>> - folio_put(folio);
> >>>>> - return false;
> >>>>> - }
> >>
> >> Hi SJ, apart from above issue, it looks that this branch need the
> >> folio_size() setting, right?
> >
> > folio_sz is effectively used by caller of damon_pa_young() only if this
> > function returns true, so this branch doesn't need to set folio_sz.
>
> __damon_pa_check_access() store last_addr, last_accessed and
> last_folio_sz, even damon_pa_young() return false, the following check
> still use last_folio_sz,
>
> ALIGN_DOWN(last_addr, last_folio_sz) == ALIGN_DOWN(r->sampling_addr,
> last_folio_sz)
>
> but last_folio_sz is not up to date, so I think it need to update, and
> update last_folio_sz is harmless, which could let's unify the return
> path, correct me if I am wrong.
Ah, you're right. Thank you for kind explanation. I was out of my mind for
some reason. Maybe we could just do 'goto out' in the branch.
Thanks,
SJ
next prev parent reply other threads:[~2023-03-07 18:00 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-03 8:43 [PATCH v2 0/3] mm/damon/paddr: minor code improvement Kefeng Wang
2023-03-03 8:43 ` [PATCH v2 1/3] mm/damon/paddr: minor refactor of damon_pa_pageout() Kefeng Wang
2023-03-03 18:41 ` SeongJae Park
2023-03-03 8:43 ` [PATCH v2 2/3] mm/damon/paddr: minor refactor of damon_pa_young() Kefeng Wang
2023-03-03 18:39 ` SeongJae Park
2023-03-06 1:10 ` Kefeng Wang
2023-03-06 1:56 ` Kefeng Wang
2023-03-06 21:27 ` SeongJae Park
2023-03-07 1:22 ` Kefeng Wang
2023-03-07 18:00 ` SeongJae Park [this message]
2023-03-08 1:03 ` Kefeng Wang
2023-03-03 8:43 ` [PATCH v2 3/3] mm/damon/paddr: minor refactor of damon_pa_mark_accessed_or_deactivate() Kefeng Wang
2023-03-03 18:26 ` SeongJae Park
2023-03-03 18:37 ` SeongJae Park
2023-03-06 1:12 ` Kefeng Wang
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=20230307180023.152415-1-sj@kernel.org \
--to=sj@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=damon@lists.linux.dev \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=wangkefeng.wang@huawei.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).