From: Wei Yang <weiyang.kernel@gmail.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: One comment on the __release_region in kernel/resource.c
Date: Mon, 3 Oct 2011 22:24:23 +0800 [thread overview]
Message-ID: <CADLM8XP5uBToExWNXiLUvHoCFV-3795rmYyJxGNOao=po+JH2Q@mail.gmail.com> (raw)
In-Reply-To: <CAMuHMdV_aKGscAw1UmQU45VZONtdvYLTK18nTYX4wvg0YLTx4A@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 1949 bytes --]
2011/10/3 Geert Uytterhoeven <geert@linux-m68k.org>
> On Mon, Oct 3, 2011 at 15:35, Wei Yang <weiyang.kernel@gmail.com> wrote:
> > 2011/10/3 Geert Uytterhoeven <geert@linux-m68k.org>
> >> On Mon, Oct 3, 2011 at 12:24, KAMEZAWA Hiroyuki
> >> <kamezawa.hiroyu@jp.fujitsu.com> wrote:
> >> > On Sun, 2 Oct 2011 21:57:07 +0800
> >> > Wei Yang <weiyang.kernel@gmail.com> wrote:
> >> >
> >> >> Dear experts,
> >> >>
> >> >> I am viewing the source code of __release_region() in
> >> >> kernel/resource.c.
> >> >> And I have one comment for the performance issue.
> >> >>
> >> >> For example, we have a resource tree like this.
> >> >> 10-89
> >> >> 20-79
> >> >> 30-49
> >> >> 55-59
> >> >> 60-64
> >> >> 65-69
> >> >> 80-89
> >> >> 100-279
> >> >>
> >> >> If the caller wants to release a region of [50,59], the original code
> >> >> will
> >> ^^^^^^^
> >> Do you really mean [50,59]?
> >
> > Yes.
> >>
> >> I don't think that's allowed, as the tree has [55,59], so you would
> >> release a
> >> larger region that allocated.
> >
> > So you mean the case I mentioned will not happen?
>
> Indeed, it should not happen.
> Actually I'm surprised it doesn't return an error code.
>
Yes, it shouldn't happen.
But it need to handle the error case.
>
> > Actually, I believe every developer should pass the resource region which
> > has been allocated.
> > While if some one made a mistake and pass a region which is not allocated
> > before and overlap
> > some "BUSY" region?
>
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
> geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker.
> But
> when I'm talking to journalists I just say "programmer" or something like
> that.
> -- Linus Torvalds
>
--
Wei Yang
Help You, Help Me
[-- Attachment #2: Type: text/html, Size: 3272 bytes --]
next prev parent reply other threads:[~2011-10-03 14:24 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-02 13:57 One comment on the __release_region in kernel/resource.c Wei Yang
2011-10-03 10:24 ` KAMEZAWA Hiroyuki
2011-10-03 11:15 ` Geert Uytterhoeven
2011-10-03 13:35 ` Wei Yang
2011-10-03 14:03 ` Geert Uytterhoeven
2011-10-03 14:24 ` Wei Yang [this message]
2011-10-04 14:17 ` Wei Yang
2011-10-03 13:30 ` Wei Yang
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='CADLM8XP5uBToExWNXiLUvHoCFV-3795rmYyJxGNOao=po+JH2Q@mail.gmail.com' \
--to=weiyang.kernel@gmail.com \
--cc=geert@linux-m68k.org \
--cc=kamezawa.hiroyu@jp.fujitsu.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.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).