Subject: Re: [PATCH v10 00/12] barrier: Add smp_cond_load_{relaxed,acquire}_timeout()

From: Catalin Marinas <[email-masked]>
Date: Wed, 25 Mar 2026 13:53:50 +0000

On Tue, Mar 17, 2026 at 09:17:05AM +0000, David Laight wrote:
> On Mon, 16 Mar 2026 23:53:22 -0700
> Ankur Arora <[email-masked]> wrote:
> > David Laight <[email-masked]> writes:
> > > On arm64 I think you could use explicit sev and wfe - but that will wake all
> > > 'sleeping' cpu; and you may not want the 'thundering herd'.  
> > 
> > Wouldn't we still have the same narrow window where the CPU disregards the IPI?
> 
> You need a 'sevl' in the interrupt exit path.

No need to, see the rule below in
https://developer.arm.com/documentation/ddi0487/maa/2983-beijhbbd:

R_XRZRK
  The Event Register for a PE is set by any of the following:
  [...]
  - An exception return.

-- 
Catalin