From: Alexander Shishkin <virtuoso@slind.org>
To: Valdis.Kletnieks@vt.edu
Cc: linux-kernel@vger.kernel.org, John Stultz <johnstul@us.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Kay Sievers <kay.sievers@vrfy.org>, Greg KH <gregkh@suse.de>,
Chris Friesen <chris.friesen@genband.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Thomas Gleixner <tglx@linutronix.de>,
Alexander Shishkin <virtuoso@slind.org>
Subject: Re: [PATCHv6 0/7] system time changes notification
Date: Thu, 11 Nov 2010 22:51:23 +0200 [thread overview]
Message-ID: <20101111205123.GC10585@shisha.kicks-ass.net> (raw)
In-Reply-To: <22542.1289507293@localhost>
On Thu, Nov 11, 2010 at 03:28:13PM -0500, Valdis.Kletnieks@vt.edu wrote:
> On Thu, 11 Nov 2010 21:29:55 +0200, Alexander Shishkin said:
>
> > Consider we want stuff like "wakeup every day at 3pm", the next wakeup
> > might be earlier than the timer we calculated last time, on system
> > time changes. We need to re-calculate it. This is necessary for all
> > repeating events.
> >
> > Say we want to wakeup at 3pm, now it's 4pm, so we schedule it in 23
> > hours. Now the system time changes to 2pm, and we would expect to
> > wakeup in one hour, but we take 25.
>
> Sorry, I tuned in late here...
>
> So the plan is that if you're not using this new interface, it will go off at
> the same absolute offset (23 hours after timer was set), but if you're using
> this interface, your timer event gets interrupted, you get woken up (say)
> 15 hours into your 23, and it's your job to decide if you need to set a
> new timer for the remaining 6, 7, 8 hours or some other number?
Yes. This interface doesn't deal with timers, it only provides notifications.
Regards,
--
Alex
next prev parent reply other threads:[~2010-11-11 20:51 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-11 19:29 Alexander Shishkin
2010-11-11 19:29 ` [PATCHv6 1/7] notify userspace about time changes Alexander Shishkin
2010-11-11 20:55 ` Arnd Bergmann
2010-11-11 19:29 ` [PATCHv6 2/7] wire up sys_time_change_notify() on ARM Alexander Shishkin
2010-11-11 19:29 ` [PATCHv6 3/7] wire up sys_time_change_notify() on x86 Alexander Shishkin
2010-11-11 19:29 ` [PATCHv6 4/7] wire up sys_time_change_notify() on ia64 Alexander Shishkin
2010-11-11 19:30 ` [PATCHv6 5/7] wire up sys_time_change_notify() on s390 Alexander Shishkin
2010-11-11 19:30 ` [PATCHv6 6/7] wire up sys_time_change_notify() on powerpc Alexander Shishkin
2010-11-11 19:30 ` [PATCHv6 7/7] wire up sys_time_change_notify() on blackfin Alexander Shishkin
2010-11-11 20:28 ` [PATCHv6 0/7] system time changes notification Valdis.Kletnieks
2010-11-11 20:51 ` Alexander Shishkin [this message]
2010-11-11 21:16 ` Thomas Gleixner
2010-11-11 22:11 ` Kyle Moffett
2010-11-11 22:36 ` john stultz
2010-11-11 23:19 ` Kyle Moffett
2010-11-11 23:41 ` john stultz
2010-11-11 23:45 ` john stultz
2010-11-11 22:50 ` Thomas Gleixner
2010-11-12 2:35 ` Davide Libenzi
2010-11-17 19:06 ` Alexander Shishkin
2010-11-17 20:42 ` Davide Libenzi
2010-11-17 21:29 ` Alexander Shishkin
2010-11-17 21:34 ` Kay Sievers
2010-11-18 15:59 ` Alexander Shishkin
2010-11-17 21:46 ` Thomas Gleixner
2010-11-18 9:49 ` Alexander Shishkin
2010-11-18 13:08 ` Artem Bityutskiy
2010-11-12 9:25 ` Alan Cox
2010-11-12 10:53 ` Richard Cochran
2010-11-12 11:25 ` Alan Cox
2010-11-12 10:47 ` Kay Sievers
2010-11-12 12:30 ` Alexander Shishkin
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