linux-kernel - [PATCH] x86/speculation: Remove redundant arch_smt

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Date:   Thu, 17 Jan 2019 02:10:59 -0800 (PST)
From:   Zhenzhong Duan <zhenzhong.duan@...cle.com>
To:     <linux-kernel@...r.kernel.org>
Cc:     <mingo@...hat.com>, <konrad.wilk@...cle.com>, <tglx@...utronix.de>,
        <dwmw@...zon.co.uk>, <bp@...e.de>, <srinivas.eeda@...cle.com>,
        <peterz@...radead.org>, <hpa@...or.com>
Subject: [PATCH] x86/speculation: Remove redundant arch_smt_update() call in
 sysfs SMT control

With commit a74cfffb03b7 ("x86/speculation: Rework SMT state change"),
arch_smt_update() is invoked from each individual CPU hotplug function.
Then the extra arch_smt_update() call in the sysfs SMT control is
redundant.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@...cle.com>
---
 kernel/cpu.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 91d5c38..c0c7f64 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -2090,10 +2090,8 @@ static int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)
 		 */
 		cpuhp_offline_cpu_device(cpu);
 	}
-	if (!ret) {
+	if (!ret)
 		cpu_smt_control = ctrlval;
-		arch_smt_update();
-	}
 	cpu_maps_update_done();
 	return ret;
 }
@@ -2104,7 +2102,6 @@ static int cpuhp_smt_enable(void)
 
 	cpu_maps_update_begin();
 	cpu_smt_control = CPU_SMT_ENABLED;
-	arch_smt_update();
 	for_each_present_cpu(cpu) {
 		/* Skip online CPUs and CPUs on offline nodes */
 		if (cpu_online(cpu) || !node_online(cpu_to_node(cpu)))
-- 
1.8.3.1