[PATCH v4 12/20] xen/sysctl: introduce CONFIG_PM_STATS

[Penny Zheng <Penny.Zheng@amd.com>]

We introduce a new Kconfig CONFIG_PM_STATS for wrapping all operations
regarding performance management statistics.
The major codes reside in xen/drivers/acpi/pmstat.c, including the
pm-statistic-related sysctl op: do_get_pm_info().
CONFIG_PM_STATS also shall depend on CONFIG_SYSCTL

Signed-off-by: Penny Zheng <Penny.Zheng@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Acked-by: Jan Beulich <jbeulich@suse.com>
---
v1 -> v2:
- rename to CONFIG_PM_STATS
- fix indention and stray semicolon
- make code movements into a new commit
- No need to wrap inline functions and declarations
---
v2 -> v3:
- sepearte functions related to do_pm_op() into a new commit
- both braces shall be moved to the line with the closing parenthesis
---
v3 -> v4:
- be consistent with the comment on the #endif
---
 xen/arch/x86/acpi/cpu_idle.c              |  2 ++
 xen/common/Kconfig                        |  8 ++++++++
 xen/common/sysctl.c                       |  2 +-
 xen/drivers/acpi/Makefile                 |  2 +-
 xen/include/acpi/cpufreq/processor_perf.h | 10 ++++++++++
 5 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/acpi/cpu_idle.c b/xen/arch/x86/acpi/cpu_idle.c
index 1dbf15b01e..974d81b4d6 100644
--- a/xen/arch/x86/acpi/cpu_idle.c
+++ b/xen/arch/x86/acpi/cpu_idle.c
@@ -1493,6 +1493,7 @@ static void amd_cpuidle_init(struct acpi_processor_power *power)
         vendor_override = -1;
 }
 
+#ifdef CONFIG_PM_STATS
 uint32_t pmstat_get_cx_nr(unsigned int cpu)
 {
     return processor_powers[cpu] ? processor_powers[cpu]->count : 0;
@@ -1612,6 +1613,7 @@ int pmstat_reset_cx_stat(unsigned int cpu)
 {
     return 0;
 }
+#endif /* CONFIG_PM_STATS */
 
 void cpuidle_disable_deep_cstate(void)
 {
diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index 712c29b1a0..9bf632973e 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -598,4 +598,12 @@ config PM_OP
 	help
 	  This option shall enable userspace performance management control
 	  to do power/performance analyzing and tuning.
+
+config PM_STATS
+	bool "Enable Performance Management Statistics"
+	depends on ACPI && HAS_CPUFREQ && SYSCTL
+	default y
+	help
+	  Enable collection of performance management statistics to aid in
+	  analyzing and tuning power/performance characteristics of the system
 endmenu
diff --git a/xen/common/sysctl.c b/xen/common/sysctl.c
index daf57fbe56..5207664252 100644
--- a/xen/common/sysctl.c
+++ b/xen/common/sysctl.c
@@ -170,7 +170,7 @@ long do_sysctl(XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl)
         op->u.availheap.avail_bytes <<= PAGE_SHIFT;
         break;
 
-#if defined (CONFIG_ACPI) && defined (CONFIG_HAS_CPUFREQ)
+#ifdef CONFIG_PM_STATS
     case XEN_SYSCTL_get_pmstat:
         ret = do_get_pm_info(&op->u.get_pmstat);
         break;
diff --git a/xen/drivers/acpi/Makefile b/xen/drivers/acpi/Makefile
index 1d811a51a7..477408afbe 100644
--- a/xen/drivers/acpi/Makefile
+++ b/xen/drivers/acpi/Makefile
@@ -5,7 +5,7 @@ obj-$(CONFIG_X86) += apei/
 obj-bin-y += tables.init.o
 obj-$(CONFIG_ACPI_NUMA) += numa.o
 obj-y += osl.o
-obj-$(CONFIG_HAS_CPUFREQ) += pmstat.o
+obj-$(CONFIG_PM_STATS) += pmstat.o
 obj-$(CONFIG_PM_OP) += pm-op.o
 
 obj-$(CONFIG_X86) += hwregs.o
diff --git a/xen/include/acpi/cpufreq/processor_perf.h b/xen/include/acpi/cpufreq/processor_perf.h
index 6de43f8602..a9a3b7a372 100644
--- a/xen/include/acpi/cpufreq/processor_perf.h
+++ b/xen/include/acpi/cpufreq/processor_perf.h
@@ -9,9 +9,19 @@
 
 unsigned int powernow_register_driver(void);
 unsigned int get_measured_perf(unsigned int cpu, unsigned int flag);
+#ifdef CONFIG_PM_STATS
 void cpufreq_statistic_update(unsigned int cpu, uint8_t from, uint8_t to);
 int  cpufreq_statistic_init(unsigned int cpu);
 void cpufreq_statistic_exit(unsigned int cpu);
+#else
+static inline void cpufreq_statistic_update(unsigned int cpu, uint8_t from,
+                                            uint8_t to) {}
+static inline int cpufreq_statistic_init(unsigned int cpu)
+{
+    return 0;
+}
+static inline void cpufreq_statistic_exit(unsigned int cpu) {}
+#endif /* CONFIG_PM_STATS */
 
 int  cpufreq_limit_change(unsigned int cpu);
 
-- 
2.34.1