From: "Okanovic, Haris" <harisokn@amazon•com>
To: "ankur.a.arora@oracle•com" <ankur.a.arora@oracle•com>,
"akpm@linux-foundation•org" <akpm@linux-foundation•org>
Cc: "joao.m.martins@oracle•com" <joao.m.martins@oracle•com>,
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<linux-arm-kernel@lists•infradead.org>,
"Okanovic, Haris" <harisokn@amazon•com>,
"rafael@kernel•org" <rafael@kernel•org>,
"linux-pm@vger•kernel.org" <linux-pm@vger•kernel.org>
Subject: Re: [PATCH v11 00/14] barrier: Add smp_cond_load_{relaxed, acquire}_timeout()
Date: Fri, 24 Apr 2026 14:16:52 +0000 [thread overview]
Message-ID: <7cd318985eebc0f068dcb77b07eab150d893b70d.camel@amazon.com> (raw)
In-Reply-To: <87tst1fpb0.fsf@oracle.com>
On Thu, 2026-04-23 at 12:29 -0700, Ankur Arora wrote:
> CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you can confirm the sender and know the content is safe.
>
>
>
> Andrew Morton <akpm@linux-foundation•org> writes:
>
> > On Wed, 8 Apr 2026 17:55:24 +0530 Ankur Arora <ankur.a.arora@oracle•com> wrote:
> >
> > > The core kernel often uses smp_cond_load_{relaxed,acquire}() to spin
> > > on condition variables with architectural primitives used to avoid
> > > hammering the relevant cachelines.
> > >
> > > ...
> > >
> > > Accordingly add two interfaces (with their generic and arm64 specific
> > > implementations):
> > >
> > > smp_cond_load_relaxed_timeout(ptr, cond_expr, time_expr, timeout)
> > > smp_cond_load_acquire_timeout(ptr, cond_expr, time_expr, timeout)
> > >
> > > Also add tif_need_resched_relaxed_wait() which wraps the polling
> > > pattern and its scheduler specific details in poll_idle().
> > > In addition add atomic_cond_read_*_timeout(),
> >
> > Thanks, I'll add this to mm.git's mm-new branch today.
>
> Great. Thanks!
>
> > This isn't am MM patchset, but mm-new isn't included in linux-next, and
> > linux-next isn't presently open for 7.1 material.
> >
> > After -rc1 I'll move the series into mm.git's mm-nonmm-unstable branch,
> > where it will get linux-next exposure.
>
> Ack that.
>
> > I see that further review/comment has been requested - hopefully this
> > will happen over the next couple of months, but please do continue to
> > chase this down if you feel the need.
>
> Will do.
>
> > > Haris Okanovic also saw improvement in real workloads due to the
> > > cpuidle changes: "observed 4-6% improvements in memcahed, cassandra,
> > > mysql, and postgresql under certain loads. Other applications likely
> > > benefit too." [12]
> >
> > Those are significant improvements. Three years :(
>
> Part of the reason was that the barrier interface was part of a series
> focused on virtualization via cpuidle-haltpoll. As that was reviewed,
> the tale changed in the telling, and it made more sense to separate
> the two.
>
> Will send out the cpuidle changes for review which Haris is running
> with.
It needs some minor refactors for latest maintain.
This is what I tested last week:
https://github.com/harisokanovic/linux/tree/dev/harisokn/arm-haltpoll-2026-april-test
>
> --
> ankur
Regards,
Haris Okanovic
AWS Graviton Software
next prev parent reply other threads:[~2026-04-24 14:17 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-08 12:25 [PATCH v11 00/14] barrier: Add smp_cond_load_{relaxed,acquire}_timeout() Ankur Arora
2026-04-08 12:25 ` [PATCH v11 01/14] asm-generic: barrier: Add smp_cond_load_relaxed_timeout() Ankur Arora
2026-05-06 7:30 ` Ankur Arora
2026-05-06 8:58 ` David Laight
2026-05-06 20:54 ` Ankur Arora
2026-05-07 9:57 ` David Laight
2026-05-08 6:31 ` Ankur Arora
2026-05-08 8:32 ` David Laight
2026-04-08 12:25 ` [PATCH v11 02/14] arm64: barrier: Support smp_cond_load_relaxed_timeout() Ankur Arora
2026-04-08 12:25 ` [PATCH v11 03/14] arm64/delay: move some constants out to a separate header Ankur Arora
2026-04-08 12:25 ` [PATCH v11 04/14] arm64: support WFET in smp_cond_load_relaxed_timeout() Ankur Arora
2026-04-08 12:25 ` [PATCH v11 05/14] arm64: rqspinlock: Remove private copy of smp_cond_load_acquire_timewait() Ankur Arora
2026-04-08 12:25 ` [PATCH v11 06/14] asm-generic: barrier: Add smp_cond_load_acquire_timeout() Ankur Arora
2026-04-08 12:25 ` [PATCH v11 07/14] atomic: Add atomic_cond_read_*_timeout() Ankur Arora
2026-04-08 12:25 ` [PATCH v11 08/14] locking/atomic: scripts: build atomic_long_cond_read_*_timeout() Ankur Arora
2026-04-08 12:25 ` [PATCH v11 09/14] bpf/rqspinlock: switch check_timeout() to a clock interface Ankur Arora
2026-04-08 12:25 ` [PATCH v11 10/14] bpf/rqspinlock: Use smp_cond_load_acquire_timeout() Ankur Arora
2026-04-08 12:25 ` [PATCH v11 11/14] sched: add need-resched timed wait interface Ankur Arora
2026-04-08 12:25 ` [PATCH v11 12/14] cpuidle/poll_state: Wait for need-resched via tif_need_resched_relaxed_wait() Ankur Arora
2026-04-20 16:57 ` Okanovic, Haris
2026-04-20 17:50 ` Ankur Arora
2026-04-21 7:15 ` Catalin Marinas
2026-04-20 22:12 ` Christoph Lameter (Ampere)
2026-04-08 12:25 ` [PATCH v11 13/14] kunit: enable testing smp_cond_load_relaxed_timeout() Ankur Arora
2026-04-08 12:25 ` [PATCH v11 14/14] kunit: add tests for smp_cond_load_relaxed_timeout() Ankur Arora
2026-05-21 8:30 ` [PATCH v11 1/2] kunit: add tests for smp_cond_load_*_timeout() Ankur Arora
2026-05-21 8:30 ` [PATCH v11 2/2] kunit: add clock tests for smp_cond_load_relaxed_timeout() Ankur Arora
2026-05-21 21:46 ` [PATCH v11 1/2] kunit: add tests for smp_cond_load_*_timeout() Andrew Morton
2026-05-21 21:57 ` Mark Brown
2026-05-22 5:10 ` Ankur Arora
2026-04-23 17:16 ` [PATCH v11 00/14] barrier: Add smp_cond_load_{relaxed,acquire}_timeout() Andrew Morton
2026-04-23 19:29 ` Ankur Arora
2026-04-24 14:16 ` Okanovic, Haris [this message]
2026-04-24 14:10 ` [PATCH v11 00/14] barrier: Add smp_cond_load_{relaxed, acquire}_timeout() Okanovic, Haris
2026-04-24 14:28 ` [PATCH v11 00/14] barrier: Add smp_cond_load_{relaxed,acquire}_timeout() Andrew Morton
2026-04-24 18:10 ` Ankur Arora
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