Can jiffies freeze?

Valdis.Kletnieks at Valdis.Kletnieks at
Wed Jan 23 10:08:12 EST 2013

On Wed, 23 Jan 2013 14:05:25 +0800, bill4carson said:

> Hmmm, all the boot messages are routed into a buffer it first printed into
> console, here there is no delay, possible tick timer are not setup yet.
> But when it does get printed into the console, this process could be
> interrupted by other action as well, that's where you see a 2sec delay.

Unlikely, unless Sandeep is running an actual serial console at a very
low speed (which *can* cause fun on large NUMA machines that spew lots
of messages).  I'm pretty convinced that Sandeep is actually seeing a
2 second delay somewhere near mm_init that isn't reflected in the timestamps
because mm_init runs before the clocks are set up.

Of course, it may not be mm_init *itself* that's causing the delay - all
we *really* know is it's somewhere between a printk in mm_init and the
previous printk - there may be something *else* in between that's the
actual time sink.

Sandeep - I admit not having tried it, but can you see if booting with
'initcall_debug' narrows down where your problem is?  If the initcall
stuff is running early enough (I'm not sure when it starts relative to
mm_init), you'll get a message from each initcall as it is entered end
exited.  With any luck, that will help narrow down exactly where your
problem is.
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