linux-kernel - Re: Timekeeping issue on aggressive suspend/resume

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1276199568.16089.35.camel@work-vm>
Date:	Thu, 10 Jun 2010 12:52:48 -0700
From:	john stultz <johnstul@...ibm.com>
To:	Suresh Rajashekara <suresh.raj+linuxomap@...il.com>
Cc:	Thomas Gleixner <tglx@...utronix.de>, linux-omap@...r.kernel.org,
	LKML <linux-kernel@...r.kernel.org>,
	linux-pm@...ts.linux-foundation.org
Subject: Re: Timekeeping issue on aggressive suspend/resume

On Wed, 2010-06-09 at 23:34 -0700, Suresh Rajashekara wrote:
> On Wed, Jun 9, 2010 at 1:22 PM, Thomas Gleixner <tglx@...utronix.de> wrote:
> > Though we could change that conditionally - the default would still be
> > the freeze of jiffies and CLOCK_MONOTONIC for historical compability.
> 
> If I were to change it only for our implementation, and make all the
> user space timers use CLOCK_REALTIME, then could you please point me
> in a direction as to what part of the kernel I should be touching to
> make that change?

I think Thomas was suggesting that you consider creating a option for
where CLOCK_MONOTONIC included total_sleep_time.

In that case the *hack* (and this is a hack, we'll need some more
thoughtful discussion before anything like it could make it upstream)
would be in timekeeping_resume() to comment out the lines that update
wall_to_monotonic and total_sleep_time.

It would be interesting to hear if that hack works for you, and we can
try to come up with a better way to think about how to accommodate both
views of how to account time over suspend.

Thomas, might this call for a new posix clock_id, CLOCK_BOOTTIME (ie:
CLOCK_MONOTONIC + total_sleep_time) or something that userland could use
to set timers on?

thanks
-john

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/