Re: [PATCH] sched_clock: fix postinit no sched_clock function check

[Will Deacon]

On Wed, Oct 02, 2013 at 05:55:28PM +0100, Santosh Shilimkar wrote:
> The sched_clock code uses 2 levels of function pointers, sched_clock_func()
> and read_sched_clock() but the no sched_clock check in postinit() just
> checks read_sched_clock().
> 
> This leads to kernel falling back to jiffy based sched clock even in
> presence of sched_clock_func() which is not desirable.
> 
> Fix the postinit() check to avoid the issue. Probably the issue is hidden
> so far on most of the arm SOCs because of already existing sched_clock
> registrations apart from arch_timer sched_clock. One can reproduce the
> issue by just have arch_timer as sched_clock

Isn't this just an issue with the arch timer driver not calling
setup_sched_clock? Instead, we munge around with sched_clock_func directly,
which doesn't appear to be the way anybody else deals with this.

I'm not sure of the history though, so perhaps there's a reason for this...

Will
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