On Wed, 16 Oct 2024, Catalin Marinas wrote:

The behaviour above is slightly different from the current poll_idle()
implementation. The above is more like poll every timeout period rather
than continuously poll until either the need_resched() condition is true
_or_ the timeout expired. From Ankur's email, an IPI may not happen so
we don't have any guarantee that WFET will wake up before the timeout.
The only way for WFE/WFET to wake up on need_resched() is to use LDXR to
arm the exclusive monitor. That's what smp_cond_load_relaxed() does.

Sorry no. The IPI will cause the WFE to continue immediately and not wait
till the end of the timeout period.