linux-kernel - [PATCH 5/5] cpuidle-haltpoll: fix up the branch check

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Message-Id: <1572060239-17401-6-git-send-email-zhenzhong.duan@oracle.com>
Date:   Sat, 26 Oct 2019 11:23:59 +0800
From:   Zhenzhong Duan <zhenzhong.duan@...cle.com>
To:     linux-kernel@...r.kernel.org
Cc:     kvm@...r.kernel.org, mtosatti@...hat.com,
        joao.m.martins@...cle.com, rafael.j.wysocki@...el.com,
        rkrcmar@...hat.com, pbonzini@...hat.com,
        Zhenzhong Duan <zhenzhong.duan@...cle.com>
Subject: [PATCH 5/5] cpuidle-haltpoll: fix up the branch check

Ensure pool time is longer than block_ns, so there is a margin to
avoid vCPU get into block state unnecessorily.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@...cle.com>
---
 drivers/cpuidle/governors/haltpoll.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/cpuidle/governors/haltpoll.c b/drivers/cpuidle/governors/haltpoll.c
index 4b00d7a..59eadaf 100644
--- a/drivers/cpuidle/governors/haltpoll.c
+++ b/drivers/cpuidle/governors/haltpoll.c
@@ -81,9 +81,9 @@ static void adjust_poll_limit(struct cpuidle_device *dev, unsigned int block_us)
 	u64 block_ns = block_us*NSEC_PER_USEC;
 
 	/* Grow cpu_halt_poll_us if
-	 * cpu_halt_poll_us < block_ns < guest_halt_poll_us
+	 * cpu_halt_poll_us <= block_ns < guest_halt_poll_us
 	 */
-	if (block_ns > dev->poll_limit_ns && block_ns <= guest_halt_poll_ns) {
+	if (block_ns >= dev->poll_limit_ns && block_ns < guest_halt_poll_ns) {
 		val = dev->poll_limit_ns * guest_halt_poll_grow;
 
 		/*
@@ -101,7 +101,7 @@ static void adjust_poll_limit(struct cpuidle_device *dev, unsigned int block_us)
 			val = guest_halt_poll_ns;
 
 		dev->poll_limit_ns = val;
-	} else if (block_ns > guest_halt_poll_ns &&
+	} else if (block_ns >= guest_halt_poll_ns &&
 		   guest_halt_poll_allow_shrink) {
 		unsigned int shrink = guest_halt_poll_shrink;
 
-- 
1.8.3.1