Re: [PATCH 07/16] sched: Make SD_BALANCE_WAKE a topology flag

From: Peter Zijlstra
Date: Wed Jun 01 2016 - 16:18:26 EST

On Mon, May 23, 2016 at 11:58:49AM +0100, Morten Rasmussen wrote:
> For systems with the SD_ASYM_CPUCAPACITY flag set on higher level in the
> sched_domain hierarchy we need a way to enable wake-up balancing for the
> lower levels as well as we may want to balance tasks that don't fit the
> capacity of the previous cpu.
> We have the option of introducing a new topology flag to express this
> requirement, or let the existing SD_BALANCE_WAKE flag be set by the
> architecture as a topology flag. The former means introducing yet
> another flag, the latter breaks the current meaning of topology flags.
> None of the options are really desirable.

So why can't you couple this to ASYM_CAPACITY? If that's set anywhere,
add BALANCE_WAKE as appropriate?