Re: [PATCH RFC] pvclock: Make pv_clock more robust and fixup it ifoverflow happens

[Igor Mammedov]

On 02/13/2012 06:48 PM, Marcelo Tosatti wrote:
> On Mon, Feb 13, 2012 at 04:45:59PM +0100, Igor Mammedov wrote:
> > Instead of hunting misterious stalls/hungs all over the kernel when
> > overflow occurs at pvclock.c:pvclock_get_nsec_offset
> >
> >      u64 delta = native_read_tsc() - shadow->tsc_timestamp;
> >
> > and introducing hooks when places of unexpected access found, pv_clock
> > should be initialized for the calling cpu if overflow condition is detected.
> >
> > Signed-off-by: Igor Mammedov<imammedo@xxxxxxxxxx>
>
> Igor,
>
> I disagree. This is fixing the symptom not the root cause. Additionally,
> Xen also uses pvclock_clocksource_read.
>
> How about adding a BUG_ON to detect the overflow, this way hunting for
> the problem is not necessary.
Ok, I'll repost bug_on version.
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