From: Valentin Schneider <valentin.schneider@arm.com>
To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
morten.rasmussen@arm.com, qperret@google.com,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>
Subject: [PATCH 1/2] sched/topology: Don't enable EAS on SMT systems
Date: Wed, 26 Feb 2020 16:41:17 +0000 [thread overview]
Message-ID: <20200226164118.6405-2-valentin.schneider@arm.com> (raw)
In-Reply-To: <20200226164118.6405-1-valentin.schneider@arm.com>
EAS already requires asymmetric CPU capacities to be enabled, and mixing
this with SMT is an aberration, but better be safe than sorry.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
---
kernel/sched/topology.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 00911884b7e7..76cd0a370b9a 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -360,6 +360,10 @@ static bool build_perf_domains(const struct cpumask *cpu_map)
goto free;
}
+ /* EAS definitely does *not* handle SMT */
+ if (sched_smt_active())
+ goto free;
+
for_each_cpu(i, cpu_map) {
/* Skip already covered CPUs. */
if (find_pd(pd, i))
--
2.24.0
next prev parent reply other threads:[~2020-02-26 16:42 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-26 16:41 [PATCH 0/2] sched, arm64: enable CONFIG_SCHED_SMT for arm64 Valentin Schneider
2020-02-26 16:41 ` Valentin Schneider [this message]
2020-02-27 13:00 ` [PATCH 1/2] sched/topology: Don't enable EAS on SMT systems Quentin Perret
2020-02-27 16:28 ` Dietmar Eggemann
2020-02-27 16:42 ` Valentin Schneider
2020-02-26 16:41 ` [PATCH 2/2] arm64: defconfig: enable CONFIG_SCHED_SMT Valentin Schneider
2020-02-27 16:32 ` [PATCH 0/2] sched, arm64: enable CONFIG_SCHED_SMT for arm64 Dietmar Eggemann
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