cpumask: convert kernel trace functions

Impact: Reduce future memory usage, use new cpumask API.

(Eventually, cpumask_var_t will be allocated based on nr_cpu_ids, not NR_CPUS).

Convert kernel trace functions to use struct cpumask API:
1) Use cpumask_copy/cpumask_test_cpu/for_each_cpu.
2) Use cpumask_var_t and alloc_cpumask_var/free_cpumask_var everywhere.
3) Use on_each_cpu instead of playing with current->cpus_allowed.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 3 insertions, 10 deletions

diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c
index a5779bd975db..eaca5ad803ff 100644
--- a/kernel/trace/trace_sysprof.c
+++ b/kernel/trace/trace_sysprof.c
@@ -196,9 +196,9 @@ static enum hrtimer_restart stack_trace_timer_fn(struct hrtimer *hrtimer)
         return HRTIMER_RESTART;
 }
 
-static void start_stack_timer(int cpu)
+static void start_stack_timer(void *unused)
 {
-        struct hrtimer *hrtimer = &per_cpu(stack_trace_hrtimer, cpu);
+        struct hrtimer *hrtimer = &__get_cpu_var(stack_trace_hrtimer);
 
         hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
         hrtimer->function = stack_trace_timer_fn;
@@ -208,14 +208,7 @@ static void start_stack_timer(int cpu)
 
 static void start_stack_timers(void)
 {
-        cpumask_t saved_mask = current->cpus_allowed;
-        int cpu;
-
-        for_each_online_cpu(cpu) {
-                set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
-                start_stack_timer(cpu);
-        }
-        set_cpus_allowed_ptr(current, &saved_mask);
+        on_each_cpu(start_stack_timer, NULL, 1);
 }
 
 static void stop_stack_timer(int cpu)