From: Michal Hocko <mhocko@kernel.org>
To: Baoquan He <bhe@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org, x86@kernel.org
Subject: Re: [PATCH] x86/mm: Remove the redundant conditional check
Date: Tue, 10 Mar 2020 15:32:40 +0100 [thread overview]
Message-ID: <20200310143240.GL8447@dhcp22.suse.cz> (raw)
In-Reply-To: <20200310142341.GG27711@MiWiFi-R3L-srv>
On Tue 10-03-20 22:23:41, Baoquan He wrote:
> On 03/10/20 at 11:10am, Michal Hocko wrote:
> > On Sun 08-03-20 09:35:11, Baoquan He wrote:
> > > In commit f70029bbaacbfa8f0 ("mm, memory_hotplug: drop CONFIG_MOVABLE_NODE"),
> > > the dependency on CONFIG_MOVABLE_NODE was removed for N_MEMORY, so the
> > > conditional check in paging_init() doesn't make any sense any more.
> > > Remove it.
> >
> > Please expand more. I would really have to refresh the intention of the
> > code but from a quick look at the code CONFIG_HIGHMEM still makes
> > N_MEMORY != N_NORMAL_MEMORY. So what what does this change mean for that
> > config?
>
> Thanks for looking into this. I was trying to explain that
> CONFIG_MOVABLE_NODE made N_MEMORY have chance to take different enum
> value.
>
> Do you think the below saying is OK to you?
>
> ~~~
> In commit f70029bbaacb ("mm, memory_hotplug: drop CONFIG_MOVABLE_NODE"),
> the dependency on CONFIG_MOVABLE_NODE was removed for N_MEMORY. Before
> commit f70029bbaacb, CONFIG_HIGHMEM && !CONFIG_MOVABLE_NODE could make
> (N_MEMORY == N_NORMAL_MEMORY) be true. After commit f70029bbaacb, N_MEMORY
> doesn't have any chance to be equal to N_NORMAL_MEMORY. So the conditional
> check in paging_init() doesn't make any sense any more. Let's remove it.
Yes this describes the matter much better. I have obviously misread the
code when looking at it this morning. Being explicit in the changelog
would have helped at least me. Thanks!
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2020-03-10 14:32 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-08 1:35 [PATCH] x86/mm: Remove the redundant conditional check Baoquan He
2020-03-10 10:10 ` Michal Hocko
2020-03-10 14:23 ` Baoquan He
2020-03-10 14:32 ` Michal Hocko [this message]
2020-03-11 1:15 ` Baoquan He
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=20200310143240.GL8447@dhcp22.suse.cz \
--to=mhocko@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=bhe@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=x86@kernel.org \
/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).