Re: [PATCH v2 03/12] sched/fair: Change the variable to hold the number of periods to 32bit integer

From: Peter Zijlstra
Date: Tue May 03 2016 - 04:48:00 EST

On Tue, May 03, 2016 at 05:54:29AM +0800, Yuyang Du wrote:
> In sched average update, a period is about 1ms, so a 32-bit unsigned
> integer can approximately hold a maximum of 49 (=2^32/1000/3600/24)
> days, which means it is big enough and 64-bit is needless.

This fails to explain _why_ 49 days is enough. And what the 49 days is
enough for.

What happens when a task sleeps for more than 49 days?