From: Ulrich Drepper <drepper@redhat.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Darren Hart <dvhltc@us.ibm.com>, Ingo Molnar <mingo@elte.hu>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Andreas Schwab <schwab@redhat.com>, Danny Feng <dfeng@redhat.com>,
Jakub Jelinek <jakub@redhat.com>,
linux-kernel@vger.kernel.org, Oleg Nesterov <oleg@redhat.com>
Subject: Re: Q: sys_futex() && timespec_valid()
Date: Fri, 25 Jun 2010 16:04:41 -0400 (EDT) [thread overview]
Message-ID: <235959492.961541277496281970.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com> (raw)
In-Reply-To: <alpine.LFD.2.00.1006252140410.18683@localhost.localdomain>
----- "Thomas Gleixner" <tglx@linutronix.de> wrote:
> tv->sec < 0 is definitely an invalid value for both CLOCK_REALTIME
> and CLOCK_MONOTONIC.
CLOCK_MONOTONIC is different but it's wrong for CLOCK_REALTIME. Why would it be invalid? Because times before Epoch will not be used? By that logic you would have to declare all values before Linus' first running kernel as invalid. None of this makes sense.
The tv_sec in timespec is of type time_t and for absolute time values the same semantics as for naked time_t values applies. The absolute time is
epoch + tv_sec + tv_nsec / 1000000000
If tv_sec is negative these are values before epoch.
If there are other interfaces with absolute timeouts they certainly should be changed as well.
--
➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖
next prev parent reply other threads:[~2010-06-25 20:05 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-25 19:20 Oleg Nesterov
2010-06-25 19:42 ` Darren Hart
2010-06-25 19:49 ` Ulrich Drepper
2010-06-25 20:11 ` Thomas Gleixner
2010-06-28 13:58 ` Oleg Nesterov
2010-06-28 14:37 ` Jakub Jelinek
2010-06-28 15:02 ` Oleg Nesterov
2010-06-25 19:56 ` Mathieu Desnoyers
2010-06-25 19:59 ` Thomas Gleixner
2010-06-25 20:04 ` Ulrich Drepper [this message]
2010-06-25 20:25 ` Thomas Gleixner
2010-06-28 15:15 ` Linus Torvalds
2010-06-28 15:29 ` Andreas Schwab
2010-06-28 15:33 ` Thomas Gleixner
2010-06-28 16:04 ` Linus Torvalds
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=235959492.961541277496281970.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com \
--to=drepper@redhat.com \
--cc=a.p.zijlstra@chello.nl \
--cc=dfeng@redhat.com \
--cc=dvhltc@us.ibm.com \
--cc=jakub@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=oleg@redhat.com \
--cc=schwab@redhat.com \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.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
all inboxes | Powered by JetHome®