From: Rusty Russell <rusty@rustcorp.com.au>
To: frankeh@watson.ibm.com
Cc: davidel@xmailserver.org, rml@tech9.net, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Fast Userspace Mutexes III.
Date: Wed, 06 Mar 2002 12:31:01 +1100 [thread overview]
Message-ID: <E16iQGk-0005ds-00@wagner.rustcorp.com.au> (raw)
In-Reply-To: Your message of "Tue, 05 Mar 2002 10:15:44 CDT." <20020305151439.457E03FE06@smtp.linux.ibm.com>
In message <20020305151439.457E03FE06@smtp.linux.ibm.com> you write:
> I agree to put it there if its not used as a means to define whether
> user locks are permitted or not. If that is the intention, then the current
> futex will need to check every access through find_vma(), which we
> both know nobody wants to do.
>
> So it can only be used for architectural hints, agreed ?
Yes. It *might* work if you don't PROT_SEM the page the semaphore is
on, but it's still a bug waiting to happen. OTOH, it'd be nice if
PROT_SEM returns EINVAL was a reliably indicator of no futex support.
This way you actually need to call the futex syscall once to see if it
works.
Cheers!
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
next prev parent reply other threads:[~2002-03-06 1:28 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-03-04 3:55 Rusty Russell
2002-03-04 19:49 ` Robert Love
2002-03-04 20:13 ` Davide Libenzi
2002-03-04 20:20 ` Matthew Kirkwood
2002-03-04 20:48 ` Hubertus Franke
2002-03-04 22:15 ` Davide Libenzi
2002-03-05 1:50 ` Robert Love
2002-03-05 2:53 ` Davide Libenzi
2002-03-05 3:45 ` Rusty Russell
2002-03-05 3:55 ` Davide Libenzi
2002-03-05 6:11 ` Rusty Russell
2002-03-05 17:23 ` Davide Libenzi
2002-03-05 15:09 ` Hubertus Franke
2002-03-05 4:30 ` Edgar Toernig
2002-03-07 1:58 ` Richard Henderson
2002-03-07 2:10 ` Davide Libenzi
2002-03-05 4:48 ` Rusty Russell
2002-03-05 15:15 ` Hubertus Franke
2002-03-06 1:31 ` Rusty Russell [this message]
2002-03-05 1:34 ` Rusty Russell
2002-03-07 1:52 ` Richard Henderson
2002-03-07 3:39 ` Rusty Russell
2002-03-07 8:48 ` Richard Henderson
2002-03-07 9:17 ` Rusty Russell
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=E16iQGk-0005ds-00@wagner.rustcorp.com.au \
--to=rusty@rustcorp.com.au \
--cc=davidel@xmailserver.org \
--cc=frankeh@watson.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=rml@tech9.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
all inboxes | Powered by JetHome®