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

[Andrew Morton]

On Sun, 15 Mar 2026 18:36:39 -0700 Ankur Arora <ankur.a.arora at oracle.com> wrote:

> Hi,
> 
> This series adds waited variants of the smp_cond_load() primitives:
> smp_cond_load_relaxed_timeout(), and smp_cond_load_acquire_timeout().
>
> ...
>

How are we to determine that this change is successful, useful, etc? 
Reduced CPU consumption?  Reduced energy usage?  Improved latencies?

>
> Finally update poll_idle() and resilient queued spinlocks to use them.

Have you identified other suitable sites for conversion?

> 
>  Documentation/atomic_t.txt           | 14 +++--
>  arch/arm64/Kconfig                   |  3 +
>  arch/arm64/include/asm/barrier.h     | 23 +++++++
>  arch/arm64/include/asm/cmpxchg.h     | 62 +++++++++++++++----
>  arch/arm64/include/asm/delay-const.h | 27 +++++++++
>  arch/arm64/include/asm/rqspinlock.h  | 85 --------------------------
>  arch/arm64/lib/delay.c               | 15 ++---
>  drivers/cpuidle/poll_state.c         | 21 +------
>  drivers/soc/qcom/rpmh-rsc.c          |  8 +--
>  include/asm-generic/barrier.h        | 90 ++++++++++++++++++++++++++++
>  include/linux/atomic.h               | 10 ++++
>  include/linux/atomic/atomic-long.h   | 18 +++---
>  include/linux/sched/idle.h           | 29 +++++++++
>  kernel/bpf/rqspinlock.c              | 77 +++++++++++++++---------
>  scripts/atomic/gen-atomic-long.sh    | 16 +++--
>  15 files changed, 320 insertions(+), 178 deletions(-)
>  create mode 100644 arch/arm64/include/asm/delay-const.h

Some sort of testing in lib/tests/ would be appropriate and useful.