Re: [PATCH] clocksource: Avoid selecting mult values that mightoverflow when adjusted

[John Stultz]

On Tue, 2011-11-08 at 13:02 +0800, Yong Zhang wrote:
> On Mon, Nov 07, 2011 at 07:09:00PM -0800, John Stultz wrote:
> > Yong: Can you also give this a test run to make sure you don't see any
> > problems?
> 
> Still get warning (3.2-rc1 + your patch):
> 
> [    0.017009] ------------[ cut here ]------------
> [    0.022156] WARNING: at /build/linux/kernel/time/timekeeping.c:828 do_timer+0x402/0x4e0()
> [    0.035917] Adjusting jiffies more then 11% (1024068096 vs 1024064000)

Ah. We're tripping the warning here in early boot. We use jiffies as the
default clocksource initially even before it is registered and the
maxadj is then set. So since its null here, any adjustment triggers the
warning.

That's easy enough to avoid. Can you give this updated version a try to
make sure I didn't miss anything else?

Thanks so much for the great testing and reports!
-john