integ/kernel/kernel-std/centos/patches/CPU-PM-expose-pm_qos_resume_latency-for-CPUs.patch
Martin, Chen 794737dac2 rebase std kernel patch to CentOS7.6 3.10.0-957.1.3
fix compile error in drbd_req.c for improper usage of
request queue API; fix warning in kernel/bpf/core.c
for implicit declaration trace call for CFLAG
-Werror-implicit-function-declaration

remove patch change is_swiotlb_buffer in lib/swiotlb.c
As change already in new kernel code base

Story: 2004521
Task: 28260
Depends-On: https://review.openstack.org/625773/

Change-Id: I4a3af98b6efe6d31e66db39302f3af8c4ff19d2c
Signed-off-by: Martin, Chen <haochuan.z.chen@intel.com>
2019-01-22 20:17:50 +08:00

61 lines
2.1 KiB
Diff

From 648072810b35e6251c6503a8e6693deeb6d0a89d Mon Sep 17 00:00:00 2001
From: Alex Shi <alex.shi@linaro.org>
Date: Thu, 12 Jan 2017 21:27:03 +0800
Subject: [PATCH] CPU / PM: expose pm_qos_resume_latency for CPUs
[ commit 37efa4b41ffb31dcdfc3beb97d47992bb2a083e5 from linux-stable ]
The cpu-dma PM QoS constraint impacts all the cpus in the system. There is no way
to let the user to choose a PM QoS constraint per cpu.
The following patch exposes to the userspace a per cpu based sysfs file
in order to let the userspace to change the value of the PM QoS latency
constraint.
This change is inoperative in its form and the cpuidle governors have to
take into account the per cpu latency constraint in addition to the
global cpu-dma latency constraint in order to operate properly.
BTW
The pm_qos_resume_latency usage defined in
Documentation/ABI/testing/sysfs-devices-power
The /sys/devices/.../power/pm_qos_resume_latency_us attribute
contains the PM QoS resume latency limit for the given device,
which is the maximum allowed time it can take to resume the
device, after it has been suspended at run time, from a resume
request to the moment the device will be ready to process I/O,
in microseconds. If it is equal to 0, however, this means that
the PM QoS resume latency may be arbitrary.
Signed-off-by: Alex Shi <alex.shi@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Alex Kozyrev <alex.kozyrev@windriver.com>
Signed-off-by: Jim Somerville <Jim.Somerville@windriver.com>
---
drivers/base/cpu.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 65e786d..91d620f 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -15,6 +15,7 @@
#include <linux/percpu.h>
#include <linux/acpi.h>
#include <linux/tick.h>
+#include <linux/pm_qos.h>
#include "base.h"
@@ -318,6 +319,7 @@ int register_cpu(struct cpu *cpu, int num)
per_cpu(cpu_sys_devices, num) = &cpu->dev;
if (!error)
register_cpu_under_node(num, cpu_to_node(num));
+ dev_pm_qos_expose_latency_limit(&cpu->dev, 0);
#ifdef CONFIG_KEXEC
if (!error)
--
2.7.4