[PATCH v4 08/12] cpufreq: convert to a single post-init driver (hooks) instance

From: "Jan Beulich" <JBeulich@suse.com>
To: xen-devel <xen-devel@lists.xenproject.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
	Wei Liu <wei.liu2@citrix.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	George Dunlap <George.Dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Ian Jackson <Ian.Jackson@eu.citrix.com>, Tim Deegan <tim@xen.org>,
	Julien Grall <julien.grall@arm.com>
Subject: [PATCH v4 08/12] cpufreq: convert to a single post-init driver (hooks) instance
Date: Tue, 02 Oct 2018 04:16:12 -0600	[thread overview]
Message-ID: <5BB3456C02000078001EDA54@prv1-mh.provo.novell.com> (raw)
In-Reply-To: <5BB343D802000078001ED9F6@prv1-mh.provo.novell.com>

This reduces the post-init memory footprint, eliminates a pointless
level of indirection at the use sites, and allows for subsequent
alternatives call patching.

Take the opportunity and also add a name to the PowerNow! instance.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
---
v2: New.

--- a/xen/arch/x86/acpi/cpufreq/cpufreq.c
+++ b/xen/arch/x86/acpi/cpufreq/cpufreq.c
@@ -53,8 +53,6 @@ enum {
 
 struct acpi_cpufreq_data *cpufreq_drv_data[NR_CPUS];
 
-static struct cpufreq_driver acpi_cpufreq_driver;
-
 static bool __read_mostly acpi_pstate_strict;
 boolean_param("acpi_pstate_strict", acpi_pstate_strict);
 
@@ -355,7 +353,7 @@ static void feature_detect(void *info)
     if ( cpu_has_aperfmperf )
     {
         policy->aperf_mperf = 1;
-        acpi_cpufreq_driver.getavg = get_measured_perf;
+        cpufreq_driver.getavg = get_measured_perf;
     }
 
     eax = cpuid_eax(6);
@@ -593,7 +591,7 @@ acpi_cpufreq_cpu_init(struct cpufreq_pol
         policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
         break;
     case ACPI_ADR_SPACE_FIXED_HARDWARE:
-        acpi_cpufreq_driver.get = get_cur_freq_on_cpu;
+        cpufreq_driver.get = get_cur_freq_on_cpu;
         policy->cur = get_cur_freq_on_cpu(cpu);
         break;
     default:
@@ -635,7 +633,7 @@ static int acpi_cpufreq_cpu_exit(struct
     return 0;
 }
 
-static struct cpufreq_driver acpi_cpufreq_driver = {
+static const struct cpufreq_driver __initconstrel acpi_cpufreq_driver = {
     .name   = "acpi-cpufreq",
     .verify = acpi_cpufreq_verify,
     .target = acpi_cpufreq_target,
@@ -656,7 +654,7 @@ static int __init cpufreq_driver_init(vo
 
     return ret;
 }
-__initcall(cpufreq_driver_init);
+presmp_initcall(cpufreq_driver_init);
 
 int cpufreq_cpu_init(unsigned int cpuid)
 {
--- a/xen/arch/x86/acpi/cpufreq/powernow.c
+++ b/xen/arch/x86/acpi/cpufreq/powernow.c
@@ -52,8 +52,6 @@
 
 #define ARCH_CPU_FLAG_RESUME	1
 
-static struct cpufreq_driver powernow_cpufreq_driver;
-
 static void transition_pstate(void *pstate)
 {
     wrmsrl(MSR_PSTATE_CTRL, *(unsigned int *)pstate);
@@ -215,7 +213,7 @@ static void feature_detect(void *info)
     if ( cpu_has_aperfmperf )
     {
         policy->aperf_mperf = 1;
-        powernow_cpufreq_driver.getavg = get_measured_perf;
+        cpufreq_driver.getavg = get_measured_perf;
     }
 
     edx = cpuid_edx(CPUID_FREQ_VOLT_CAPABILITIES);
@@ -347,7 +345,8 @@ static int powernow_cpufreq_cpu_exit(str
     return 0;
 }
 
-static struct cpufreq_driver powernow_cpufreq_driver = {
+static const struct cpufreq_driver __initconstrel powernow_cpufreq_driver = {
+    .name   = "powernow",
     .verify = powernow_cpufreq_verify,
     .target = powernow_cpufreq_target,
     .init   = powernow_cpufreq_cpu_init,
--- a/xen/drivers/acpi/pmstat.c
+++ b/xen/drivers/acpi/pmstat.c
@@ -64,7 +64,7 @@ int do_get_pm_info(struct xen_sysctl_get
     case PMSTAT_PX:
         if ( !(xen_processor_pmbits & XEN_PROCESSOR_PM_PX) )
             return -ENODEV;
-        if ( !cpufreq_driver )
+        if ( !cpufreq_driver.init )
             return -ENODEV;
         if ( !pmpt || !(pmpt->perf.init & XEN_PX_INIT) )
             return -EINVAL;
@@ -255,16 +255,16 @@ static int get_cpufreq_para(struct xen_s
         return ret;
 
     op->u.get_para.cpuinfo_cur_freq =
-        cpufreq_driver->get ? cpufreq_driver->get(op->cpuid) : policy->cur;
+        cpufreq_driver.get ? cpufreq_driver.get(op->cpuid) : policy->cur;
     op->u.get_para.cpuinfo_max_freq = policy->cpuinfo.max_freq;
     op->u.get_para.cpuinfo_min_freq = policy->cpuinfo.min_freq;
     op->u.get_para.scaling_cur_freq = policy->cur;
     op->u.get_para.scaling_max_freq = policy->max;
     op->u.get_para.scaling_min_freq = policy->min;
 
-    if ( cpufreq_driver->name[0] )
+    if ( cpufreq_driver.name[0] )
         strlcpy(op->u.get_para.scaling_driver, 
-            cpufreq_driver->name, CPUFREQ_NAME_LEN);
+            cpufreq_driver.name, CPUFREQ_NAME_LEN);
     else
         strlcpy(op->u.get_para.scaling_driver, "Unknown", CPUFREQ_NAME_LEN);
 
--- a/xen/drivers/cpufreq/cpufreq.c
+++ b/xen/drivers/cpufreq/cpufreq.c
@@ -172,7 +172,7 @@ int cpufreq_add_cpu(unsigned int cpu)
     if ( !(perf->init & XEN_PX_INIT) )
         return -EINVAL;
 
-    if (!cpufreq_driver)
+    if (!cpufreq_driver.init)
         return 0;
 
     if (per_cpu(cpufreq_cpu_policy, cpu))
@@ -239,7 +239,7 @@ int cpufreq_add_cpu(unsigned int cpu)
         policy->cpu = cpu;
         per_cpu(cpufreq_cpu_policy, cpu) = policy;
 
-        ret = cpufreq_driver->init(policy);
+        ret = cpufreq_driver.init(policy);
         if (ret) {
             free_cpumask_var(policy->cpus);
             xfree(policy);
@@ -298,7 +298,7 @@ err1:
     cpumask_clear_cpu(cpu, cpufreq_dom->map);
 
     if (cpumask_empty(policy->cpus)) {
-        cpufreq_driver->exit(policy);
+        cpufreq_driver.exit(policy);
         free_cpumask_var(policy->cpus);
         xfree(policy);
     }
@@ -362,7 +362,7 @@ int cpufreq_del_cpu(unsigned int cpu)
     cpumask_clear_cpu(cpu, cpufreq_dom->map);
 
     if (cpumask_empty(policy->cpus)) {
-        cpufreq_driver->exit(policy);
+        cpufreq_driver.exit(policy);
         free_cpumask_var(policy->cpus);
         xfree(policy);
     }
@@ -663,17 +663,17 @@ static int __init cpufreq_presmp_init(vo
 }
 presmp_initcall(cpufreq_presmp_init);
 
-int __init cpufreq_register_driver(struct cpufreq_driver *driver_data)
+int __init cpufreq_register_driver(const struct cpufreq_driver *driver_data)
 {
    if ( !driver_data || !driver_data->init ||
         !driver_data->verify || !driver_data->exit ||
         (!driver_data->target == !driver_data->setpolicy) )
         return -EINVAL;
 
-    if ( cpufreq_driver )
+    if ( cpufreq_driver.init )
         return -EBUSY;
 
-    cpufreq_driver = driver_data;
+    cpufreq_driver = *driver_data;
 
     return 0;
 }
--- a/xen/drivers/cpufreq/utility.c
+++ b/xen/drivers/cpufreq/utility.c
@@ -31,7 +31,7 @@
 #include <acpi/cpufreq/cpufreq.h>
 #include <public/sysctl.h>
 
-struct cpufreq_driver   *cpufreq_driver;
+struct cpufreq_driver __read_mostly cpufreq_driver;
 struct processor_pminfo *__read_mostly processor_pminfo[NR_CPUS];
 DEFINE_PER_CPU_READ_MOSTLY(struct cpufreq_policy *, cpufreq_cpu_policy);
 
@@ -360,11 +360,11 @@ int __cpufreq_driver_target(struct cpufr
 {
     int retval = -EINVAL;
 
-    if (cpu_online(policy->cpu) && cpufreq_driver->target)
+    if (cpu_online(policy->cpu) && cpufreq_driver.target)
     {
         unsigned int prev_freq = policy->cur;
 
-        retval = cpufreq_driver->target(policy, target_freq, relation);
+        retval = cpufreq_driver.target(policy, target_freq, relation);
         if ( retval == 0 )
             TRACE_2D(TRC_PM_FREQ_CHANGE, prev_freq/1000, policy->cur/1000);
     }
@@ -380,9 +380,9 @@ int cpufreq_driver_getavg(unsigned int c
     if (!cpu_online(cpu) || !(policy = per_cpu(cpufreq_cpu_policy, cpu)))
         return 0;
 
-    if (cpufreq_driver->getavg)
+    if (cpufreq_driver.getavg)
     {
-        freq_avg = cpufreq_driver->getavg(cpu, flag);
+        freq_avg = cpufreq_driver.getavg(cpu, flag);
         if (freq_avg > 0)
             return freq_avg;
     }
@@ -412,9 +412,9 @@ int cpufreq_update_turbo(int cpuid, int
         return 0;
 
     policy->turbo = new_state;
-    if (cpufreq_driver->update)
+    if (cpufreq_driver.update)
     {
-        ret = cpufreq_driver->update(cpuid, policy);
+        ret = cpufreq_driver.update(cpuid, policy);
         if (ret)
             policy->turbo = curr_state;
     }
@@ -450,15 +450,15 @@ int __cpufreq_set_policy(struct cpufreq_
         return -EINVAL;
 
     /* verify the cpu speed can be set within this limit */
-    ret = cpufreq_driver->verify(policy);
+    ret = cpufreq_driver.verify(policy);
     if (ret)
         return ret;
 
     data->min = policy->min;
     data->max = policy->max;
     data->limits = policy->limits;
-    if (cpufreq_driver->setpolicy)
-        return cpufreq_driver->setpolicy(data);
+    if (cpufreq_driver.setpolicy)
+        return cpufreq_driver.setpolicy(data);
 
     if (policy->governor != data->governor) {
         /* save old, working values */
--- a/xen/include/acpi/cpufreq/cpufreq.h
+++ b/xen/include/acpi/cpufreq/cpufreq.h
@@ -153,7 +153,7 @@ __cpufreq_governor(struct cpufreq_policy
 #define CPUFREQ_RELATION_H 1  /* highest frequency below or at target */
 
 struct cpufreq_driver {
-    char   name[CPUFREQ_NAME_LEN];
+    const char *name;
     int    (*init)(struct cpufreq_policy *policy);
     int    (*verify)(struct cpufreq_policy *policy);
     int    (*setpolicy)(struct cpufreq_policy *policy);
@@ -166,9 +166,9 @@ struct cpufreq_driver {
     int    (*exit)(struct cpufreq_policy *policy);
 };
 
-extern struct cpufreq_driver *cpufreq_driver;
+extern struct cpufreq_driver cpufreq_driver;
 
-int cpufreq_register_driver(struct cpufreq_driver *);
+int cpufreq_register_driver(const struct cpufreq_driver *);
 
 static __inline__
 void cpufreq_verify_within_limits(struct cpufreq_policy *policy,




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