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perf_counter: provide pagefault software events 

We use the generic software counter infrastructure to provide
page fault events.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2009-03-13 12:21:33 +01:00 committed by Ingo Molnar
parent 15dbf27cc1
commit 7dd1fcc258
3 changed files with 9 additions and 50 deletions
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3
arch/powerpc/mm/fault.c
View File

@ -29,6 +29,7 @@
#include <linux/module.h> #include <linux/module.h>
#include <linux/kprobes.h> #include <linux/kprobes.h>
#include <linux/kdebug.h> #include <linux/kdebug.h>
#include <linux/perf_counter.h>
#include <asm/firmware.h> #include <asm/firmware.h>
#include <asm/page.h> #include <asm/page.h>
@ -170,6 +171,8 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
die("Weird page fault", regs, SIGSEGV); die("Weird page fault", regs, SIGSEGV);
} }
perf_swcounter_event(PERF_COUNT_PAGE_FAULTS, 1, 0, regs);
/* When running in the kernel we expect faults to occur only to /* When running in the kernel we expect faults to occur only to
* addresses in user space. All other faults represent errors in the * addresses in user space. All other faults represent errors in the
* kernel and should generate an OOPS. Unfortunately, in the case of an * kernel and should generate an OOPS. Unfortunately, in the case of an

3
arch/x86/mm/fault.c
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@ -27,6 +27,7 @@
#include <linux/tty.h> #include <linux/tty.h>
#include <linux/smp.h> #include <linux/smp.h>
#include <linux/mm.h> #include <linux/mm.h>
#include <linux/perf_counter.h>
#include <asm-generic/sections.h> #include <asm-generic/sections.h>
@ -1044,6 +1045,8 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code)
if (unlikely(error_code & PF_RSVD)) if (unlikely(error_code & PF_RSVD))
pgtable_bad(regs, error_code, address); pgtable_bad(regs, error_code, address);
perf_swcounter_event(PERF_COUNT_PAGE_FAULTS, 1, 0, regs);
/* /*
* If we're in an interrupt, have no user context or are running * If we're in an interrupt, have no user context or are running
* in an atomic region then we must not take the fault: * in an atomic region then we must not take the fault:

53
kernel/perf_counter.c
View File

@ -1607,57 +1607,10 @@ static const struct hw_perf_counter_ops perf_ops_task_clock = {
* Software counter: page faults * Software counter: page faults
*/ */
#ifdef CONFIG_VM_EVENT_COUNTERS
#define cpu_page_faults() __get_cpu_var(vm_event_states).event[PGFAULT]
#else
#define cpu_page_faults() 0
#endif
static u64 get_page_faults(struct perf_counter *counter)
{
struct task_struct *curr = counter->ctx->task;
if (curr)
return curr->maj_flt + curr->min_flt;
return cpu_page_faults();
}
static void page_faults_perf_counter_update(struct perf_counter *counter)
{
u64 prev, now;
s64 delta;
prev = atomic64_read(&counter->hw.prev_count);
now = get_page_faults(counter);
atomic64_set(&counter->hw.prev_count, now);
delta = now - prev;
atomic64_add(delta, &counter->count);
}
static void page_faults_perf_counter_read(struct perf_counter *counter)
{
page_faults_perf_counter_update(counter);
}
static int page_faults_perf_counter_enable(struct perf_counter *counter)
{
if (counter->prev_state <= PERF_COUNTER_STATE_OFF)
atomic64_set(&counter->hw.prev_count, get_page_faults(counter));
return 0;
}
static void page_faults_perf_counter_disable(struct perf_counter *counter)
{
page_faults_perf_counter_update(counter);
}
static const struct hw_perf_counter_ops perf_ops_page_faults = { static const struct hw_perf_counter_ops perf_ops_page_faults = {
.enable = page_faults_perf_counter_enable, .enable = perf_swcounter_enable,
.disable = page_faults_perf_counter_disable, .disable = perf_swcounter_disable,
.read = page_faults_perf_counter_read, .read = perf_swcounter_read,
}; };
/* /*