linux-kernel - [PATCH RESEND] Calling check_system_tsc_reliable() before unsynchronized

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Message-ID: <b1532ef7-cd9f-45f7-9f49-48dd2a5c2495@default>
Date:   Wed, 21 Jun 2017 01:23:37 -0700 (PDT)
From:   Zhenzhong Duan <zhenzhong.duan@...cle.com>
To:     <mingo@...hat.com>, <tglx@...utronix.de>, <hpa@...or.com>
Cc:     <x86@...nel.org>, Zhenzhong Duan <zhenzhong.duan@...cle.com>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH RESEND] Calling check_system_tsc_reliable() before
 unsynchronized_tsc()

unsynchronized_tsc() checks value of tsc_clocksource_reliable which is set by
check_system_tsc_reliable(). It's better to move check_system_tsc_reliable() at
front.

Though X86_FEATURE_CONSTANT_TSC is usually set for TSC reliable system, just in
case.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@...cle.com>
---
 arch/x86/kernel/tsc.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 714dfba..a316bdd 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1412,11 +1412,11 @@ void __init tsc_init(void)
 
 	use_tsc_delay();
 
+	check_system_tsc_reliable();
+
 	if (unsynchronized_tsc())
 		mark_tsc_unstable("TSCs unsynchronized");
 
-	check_system_tsc_reliable();
-
 	detect_art();
 }
 
-- 
1.7.3