From: Peter Zijlstra <peterz@infradead.org>
To: Andrea Righi <arighi@nvidia.com>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>,
Ingo Molnar <mingo@redhat.com>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Valentin Schneider <vschneid@redhat.com>,
Christian Loehle <christian.loehle@arm.com>,
Koba Ko <kobak@nvidia.com>,
Felix Abecassis <fabecassis@nvidia.com>,
Balbir Singh <balbirs@nvidia.com>,
Joel Fernandes <joelagnelf@nvidia.com>,
Shrikanth Hegde <sshegde@linux.ibm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/6] sched/fair: Use guard(rcu) for sched_domain RCU sections
Date: Tue, 28 Apr 2026 13:50:17 +0200 [thread overview]
Message-ID: <20260428115017.GW3102624@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <afCPSnkepnRqzWdt@gpd4>
On Tue, Apr 28, 2026 at 12:43:22PM +0200, Andrea Righi wrote:
> > and since this is only called from:
> >
> > sched_tick() /* IRQs disabled */
> > sched_balance_trigger()
> > nohz_balancer_kick()
> >
> > with IRQs disabled, we can get rid of that rcu_read_lock() entirely.
>
> Yeah, all makes sense. I'll update the patch dropping rcu_read_lock/unlock()
> completely.
>
> Is it worth adding a lockdep_assert_irqs_disabled()?
I think the rcu_dereference_all() thing will go scream if it doesn't
have any of IRQs/preempt/rcu disabled.
next prev parent reply other threads:[~2026-04-28 11:50 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-28 5:16 [PATCH v4 0/6] sched/fair: SMT-aware asymmetric CPU capacity Andrea Righi
2026-04-28 5:16 ` [PATCH 1/6] sched/fair: Use guard(rcu) for sched_domain RCU sections Andrea Righi
2026-04-28 8:33 ` K Prateek Nayak
2026-04-28 10:43 ` Andrea Righi
2026-04-28 11:04 ` K Prateek Nayak
2026-04-28 11:50 ` Peter Zijlstra [this message]
2026-04-28 13:16 ` Andrea Righi
2026-04-28 14:12 ` Steven Rostedt
2026-04-28 14:26 ` Andrea Righi
2026-04-28 14:29 ` Steven Rostedt
2026-04-28 5:16 ` [PATCH 2/6] sched/fair: Attach sched_domain_shared to sd_asym_cpucapacity Andrea Righi
2026-04-28 6:45 ` Shrikanth Hegde
2026-04-28 8:47 ` Andrea Righi
2026-04-28 5:16 ` [PATCH 3/6] sched/fair: Prefer fully-idle SMT cores in asym-capacity idle selection Andrea Righi
2026-04-28 5:16 ` [PATCH 4/6] sched/fair: Reject misfit pulls onto busy SMT siblings on asym-capacity Andrea Righi
2026-04-28 5:16 ` [PATCH 5/6] sched/fair: Add SIS_UTIL support to select_idle_capacity() Andrea Righi
2026-04-28 5:16 ` [PATCH 6/6] sched/topology: Remove SMT/asym capacity warning Andrea Righi
2026-04-28 5:28 ` K Prateek Nayak
2026-04-28 5:54 ` Andrea Righi
2026-04-28 6:04 ` Andrea Righi
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