Re: [RFC PATCH v2 1/2] sched: Document WF_SYNC wakeup placement semantics

[Peter Zijlstra]

On Thu, Sep 17, 2026 at 01:43:24PM -0700, Shubhang Kaushik (Ampere) wrote:
> WF_SYNC is supplied by callers that expect the waker to schedule away
> soon. The fair scheduler can use it as a placement and preemption hint,
> but its semantics are not documented.
> 
> Document the stable fair-class WF_SYNC semantics. WF_SYNC is advisory:
> it can influence placement and preemption, but does not guarantee CPU
> locality, avoidance of migration, or immediate wakee preemption.
> 
> This documents existing behavior only. It does not establish a new
> WF_SYNC placement policy.
> 
> Signed-off-by: Shubhang Kaushik (Ampere) <sh@xxxxxxxxxx>

*groan*, why not just a comment that goes with WF_SYNC? All this
documentation stuff is a dumping ground for bitrot.