From: Charles Forsyth <charles.forsyth@gmail.com>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: Re: [9fans] imagereclaim()
Date: Sat, 1 Mar 2014 23:14:52 +0000 [thread overview]
Message-ID: <CAOw7k5gsC5JVQnq286yOyYpJzDvqGV9mBwq9au0-Wm1P3DLXqA@mail.gmail.com> (raw)
In-Reply-To: <a1f84250a374d4e3c820df401d306396@felloff.net>
[-- Attachment #1: Type: text/plain, Size: 672 bytes --]
On 1 March 2014 23:05, <cinap_lenrek@felloff.net> wrote:
> how is this possible? the old page is locked during the call
> to duppage(). so duppage() will not run concurrently on the
> same page.
>
there's a race to decide whether to do it, and what happens to the page
once it has. it reaches back into the page load code.
you can easily end up with many copies of the same page. worse, duppage
calls a putmmu/mmuput,
which in some implementations calls newpage, which can lead to deadlock,
since duppage has the conch.
the whole thing is meant well, but misconceived. i can't even remember the
details since it's so long since i
cut out all that stuff.
[-- Attachment #2: Type: text/html, Size: 1151 bytes --]
next prev parent reply other threads:[~2014-03-01 23:14 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-01 21:46 cinap_lenrek
2014-03-01 21:55 ` erik quanstrom
2014-03-01 22:22 ` cinap_lenrek
2014-03-01 22:52 ` erik quanstrom
2014-03-01 23:05 ` cinap_lenrek
2014-03-01 23:11 ` erik quanstrom
2014-03-01 23:14 ` Charles Forsyth [this message]
2014-03-02 1:21 ` cinap_lenrek
2014-03-02 3:14 ` erik quanstrom
2014-03-02 3:55 ` cinap_lenrek
2014-03-02 4:05 ` erik quanstrom
2014-03-02 4:30 ` cinap_lenrek
2014-03-02 9:48 ` Charles Forsyth
2014-03-02 18:46 ` cinap_lenrek
2014-03-02 18:53 ` Charles Forsyth
2014-03-02 22:59 ` Anthony Martin
2014-03-03 1:00 ` erik quanstrom
2014-03-01 23:09 ` Charles Forsyth
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=CAOw7k5gsC5JVQnq286yOyYpJzDvqGV9mBwq9au0-Wm1P3DLXqA@mail.gmail.com \
--to=charles.forsyth@gmail.com \
--cc=9fans@9fans.net \
/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).