linux-kernel - [PATCH AUTOSEL for 4.9 03/55] cpupower : Fix cpupower working when cpu0 is offline

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Message-ID: <20180124041521.32223-3-alexander.levin@microsoft.com>
Date:   Wed, 24 Jan 2018 04:15:29 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
CC:     Abhishek Goel <huntbag@...ux.vnet.ibm.com>,
        Shuah Khan <shuahkh@....samsung.com>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL for 4.9 03/55] cpupower : Fix cpupower working when
 cpu0 is offline

From: Abhishek Goel <huntbag@...ux.vnet.ibm.com>

[ Upstream commit dbdc468f35ee827cab2753caa1c660bdb832243a ]

cpuidle_monitor used to assume that cpu0 is always online which is not
a valid assumption on POWER machines. This patch fixes this by getting
the cpu on which the current thread is running, instead of always using
cpu0 for monitoring which may not be online.

Signed-off-by: Abhishek Goel <huntbag@...ux.vnet.ibm.com>
Signed-off-by: Shuah Khan <shuahkh@....samsung.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c b/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c
index 1b5da0066ebf..5b3205f16217 100644
--- a/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c
+++ b/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c
@@ -130,15 +130,18 @@ static struct cpuidle_monitor *cpuidle_register(void)
 {
 	int num;
 	char *tmp;
+	int this_cpu;
+
+	this_cpu = sched_getcpu();
 
 	/* Assume idle state count is the same for all CPUs */
-	cpuidle_sysfs_monitor.hw_states_num = cpuidle_state_count(0);
+	cpuidle_sysfs_monitor.hw_states_num = cpuidle_state_count(this_cpu);
 
 	if (cpuidle_sysfs_monitor.hw_states_num <= 0)
 		return NULL;
 
 	for (num = 0; num < cpuidle_sysfs_monitor.hw_states_num; num++) {
-		tmp = cpuidle_state_name(0, num);
+		tmp = cpuidle_state_name(this_cpu, num);
 		if (tmp == NULL)
 			continue;
 
@@ -146,7 +149,7 @@ static struct cpuidle_monitor *cpuidle_register(void)
 		strncpy(cpuidle_cstates[num].name, tmp, CSTATE_NAME_LEN - 1);
 		free(tmp);
 
-		tmp = cpuidle_state_desc(0, num);
+		tmp = cpuidle_state_desc(this_cpu, num);
 		if (tmp == NULL)
 			continue;
 		strncpy(cpuidle_cstates[num].desc, tmp,	CSTATE_DESC_LEN - 1);
-- 
2.11.0