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Subject[PATCH 09/10] x86: oprofile: remove NR_CPUS arrays in arch/x86/oprofile/nmi_int.c
Change the following arrays sized by NR_CPUS to be PERCPU variables:

static struct op_msrs cpu_msrs[NR_CPUS];
static unsigned long saved_lvtpc[NR_CPUS];

Also some minor complaints from checkpatch.pl fixed.

Based on linux-2.6.25-rc5-mm1

Cc: Philippe Elie <phil.el@wanadoo.fr>

Signed-off-by: Mike Travis <travis@sgi.com>
---
All changes were transparent except for:

static void nmi_shutdown(void)
{
+ struct op_msrs *msrs = &__get_cpu_var(cpu_msrs);
nmi_enabled = 0;
on_each_cpu(nmi_cpu_shutdown, NULL, 0, 1);
unregister_die_notifier(&profile_exceptions_nb);
- model->shutdown(cpu_msrs);
+ model->shutdown(msrs);
free_msrs();
}
The existing code passed a reference to cpu 0's instance of struct op_msrs
to model->shutdown, whilst the other functions are passed a reference to
<this cpu's> instance of a struct op_msrs. This seemed to be a bug to me
even though as long as cpu 0 and <this cpu> are of the same type it would
have the same effect...?
---
arch/x86/oprofile/nmi_int.c | 49 ++++++++++++++++++++++++--------------------
1 file changed, 27 insertions(+), 22 deletions(-)
--- linux-2.6.25-rc5.orig/arch/x86/oprofile/nmi_int.c
+++ linux-2.6.25-rc5/arch/x86/oprofile/nmi_int.c
@@ -23,8 +23,8 @@
#include "op_x86_model.h"

static struct op_x86_model_spec const *model;
-static struct op_msrs cpu_msrs[NR_CPUS];
-static unsigned long saved_lvtpc[NR_CPUS];
+static DEFINE_PER_CPU(struct op_msrs, cpu_msrs);
+static DEFINE_PER_CPU(unsigned long, saved_lvtpc);

static int nmi_start(void);
static void nmi_stop(void);
@@ -89,7 +89,7 @@ static int profile_exceptions_notify(str

switch (val) {
case DIE_NMI:
- if (model->check_ctrs(args->regs, &cpu_msrs[cpu]))
+ if (model->check_ctrs(args->regs, &per_cpu(cpu_msrs, cpu)))
ret = NOTIFY_STOP;
break;
default:
@@ -126,7 +126,7 @@ static void nmi_cpu_save_registers(struc
static void nmi_save_registers(void *dummy)
{
int cpu = smp_processor_id();
- struct op_msrs *msrs = &cpu_msrs[cpu];
+ struct op_msrs *msrs = &per_cpu(cpu_msrs, cpu);
nmi_cpu_save_registers(msrs);
}

@@ -134,10 +134,10 @@ static void free_msrs(void)
{
int i;
for_each_possible_cpu(i) {
- kfree(cpu_msrs[i].counters);
- cpu_msrs[i].counters = NULL;
- kfree(cpu_msrs[i].controls);
- cpu_msrs[i].controls = NULL;
+ kfree(per_cpu(cpu_msrs, i).counters);
+ per_cpu(cpu_msrs, i).counters = NULL;
+ kfree(per_cpu(cpu_msrs, i).controls);
+ per_cpu(cpu_msrs, i).controls = NULL;
}
}

@@ -149,13 +149,15 @@ static int allocate_msrs(void)

int i;
for_each_possible_cpu(i) {
- cpu_msrs[i].counters = kmalloc(counters_size, GFP_KERNEL);
- if (!cpu_msrs[i].counters) {
+ per_cpu(cpu_msrs, i).counters = kmalloc(counters_size,
+ GFP_KERNEL);
+ if (!per_cpu(cpu_msrs, i).counters) {
success = 0;
break;
}
- cpu_msrs[i].controls = kmalloc(controls_size, GFP_KERNEL);
- if (!cpu_msrs[i].controls) {
+ per_cpu(cpu_msrs, i).controls = kmalloc(controls_size,
+ GFP_KERNEL);
+ if (!per_cpu(cpu_msrs, i).controls) {
success = 0;
break;
}
@@ -170,11 +172,11 @@ static int allocate_msrs(void)
static void nmi_cpu_setup(void *dummy)
{
int cpu = smp_processor_id();
- struct op_msrs *msrs = &cpu_msrs[cpu];
+ struct op_msrs *msrs = &per_cpu(cpu_msrs, cpu);
spin_lock(&oprofilefs_lock);
model->setup_ctrs(msrs);
spin_unlock(&oprofilefs_lock);
- saved_lvtpc[cpu] = apic_read(APIC_LVTPC);
+ per_cpu(saved_lvtpc, cpu) = apic_read(APIC_LVTPC);
apic_write(APIC_LVTPC, APIC_DM_NMI);
}

@@ -203,13 +205,15 @@ static int nmi_setup(void)
*/

/* Assume saved/restored counters are the same on all CPUs */
- model->fill_in_addresses(&cpu_msrs[0]);
+ model->fill_in_addresses(&per_cpu(cpu_msrs, 0));
for_each_possible_cpu(cpu) {
if (cpu != 0) {
- memcpy(cpu_msrs[cpu].counters, cpu_msrs[0].counters,
+ memcpy(per_cpu(cpu_msrs, cpu).counters,
+ per_cpu(cpu_msrs, 0).counters,
sizeof(struct op_msr) * model->num_counters);

- memcpy(cpu_msrs[cpu].controls, cpu_msrs[0].controls,
+ memcpy(per_cpu(cpu_msrs, cpu).controls,
+ per_cpu(cpu_msrs, 0).controls,
sizeof(struct op_msr) * model->num_controls);
}

@@ -249,7 +253,7 @@ static void nmi_cpu_shutdown(void *dummy
{
unsigned int v;
int cpu = smp_processor_id();
- struct op_msrs *msrs = &cpu_msrs[cpu];
+ struct op_msrs *msrs = &__get_cpu_var(cpu_msrs);

/* restoring APIC_LVTPC can trigger an apic error because the delivery
* mode and vector nr combination can be illegal. That's by design: on
@@ -258,23 +262,24 @@ static void nmi_cpu_shutdown(void *dummy
*/
v = apic_read(APIC_LVTERR);
apic_write(APIC_LVTERR, v | APIC_LVT_MASKED);
- apic_write(APIC_LVTPC, saved_lvtpc[cpu]);
+ apic_write(APIC_LVTPC, per_cpu(saved_lvtpc, cpu));
apic_write(APIC_LVTERR, v);
nmi_restore_registers(msrs);
}

static void nmi_shutdown(void)
{
+ struct op_msrs *msrs = &__get_cpu_var(cpu_msrs);
nmi_enabled = 0;
on_each_cpu(nmi_cpu_shutdown, NULL, 0, 1);
unregister_die_notifier(&profile_exceptions_nb);
- model->shutdown(cpu_msrs);
+ model->shutdown(msrs);
free_msrs();
}

static void nmi_cpu_start(void *dummy)
{
- struct op_msrs const *msrs = &cpu_msrs[smp_processor_id()];
+ struct op_msrs const *msrs = &__get_cpu_var(cpu_msrs);
model->start(msrs);
}

@@ -286,7 +291,7 @@ static int nmi_start(void)

static void nmi_cpu_stop(void *dummy)
{
- struct op_msrs const *msrs = &cpu_msrs[smp_processor_id()];
+ struct op_msrs const *msrs = &__get_cpu_var(cpu_msrs);
model->stop(msrs);
}

--


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