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>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 0e91f43..5d04e27 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -89,10 +89,10 @@
preempt_enable();
}
-static cpumask_t __read_mostly tracing_buffer_mask;
+static cpumask_var_t __read_mostly tracing_buffer_mask;
#define for_each_tracing_cpu(cpu) \
- for_each_cpu_mask(cpu, tracing_buffer_mask)
+ for_each_cpu(cpu, tracing_buffer_mask)
/*
* ftrace_dump_on_oops - variable to dump ftrace buffer on oops
@@ -2646,13 +2646,7 @@
/*
* Only trace on a CPU if the bitmask is set:
*/
-static cpumask_t tracing_cpumask = CPU_MASK_ALL;
-
-/*
- * When tracing/tracing_cpu_mask is modified then this holds
- * the new bitmask we are about to install:
- */
-static cpumask_t tracing_cpumask_new;
+static cpumask_var_t tracing_cpumask;
/*
* The tracer itself will not take this lock, but still we want
@@ -2674,7 +2668,7 @@
mutex_lock(&tracing_cpumask_update_lock);
- len = cpumask_scnprintf(mask_str, count, &tracing_cpumask);
+ len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
if (count - len < 2) {
count = -EINVAL;
goto out_err;
@@ -2693,9 +2687,13 @@
size_t count, loff_t *ppos)
{
int err, cpu;
+ cpumask_var_t tracing_cpumask_new;
+
+ if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
+ return -ENOMEM;
mutex_lock(&tracing_cpumask_update_lock);
- err = cpumask_parse_user(ubuf, count, &tracing_cpumask_new);
+ err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
if (err)
goto err_unlock;
@@ -2706,26 +2704,28 @@
* Increase/decrease the disabled counter if we are
* about to flip a bit in the cpumask:
*/
- if (cpu_isset(cpu, tracing_cpumask) &&
- !cpu_isset(cpu, tracing_cpumask_new)) {
+ if (cpumask_test_cpu(cpu, tracing_cpumask) &&
+ !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
atomic_inc(&global_trace.data[cpu]->disabled);
}
- if (!cpu_isset(cpu, tracing_cpumask) &&
- cpu_isset(cpu, tracing_cpumask_new)) {
+ if (!cpumask_test_cpu(cpu, tracing_cpumask) &&
+ cpumask_test_cpu(cpu, tracing_cpumask_new)) {
atomic_dec(&global_trace.data[cpu]->disabled);
}
}
__raw_spin_unlock(&ftrace_max_lock);
local_irq_enable();
- tracing_cpumask = tracing_cpumask_new;
+ cpumask_copy(tracing_cpumask, tracing_cpumask_new);
mutex_unlock(&tracing_cpumask_update_lock);
+ free_cpumask_var(tracing_cpumask_new);
return count;
err_unlock:
mutex_unlock(&tracing_cpumask_update_lock);
+ free_cpumask_var(tracing_cpumask);
return err;
}
@@ -3752,7 +3752,6 @@
static DEFINE_SPINLOCK(ftrace_dump_lock);
/* use static because iter can be a bit big for the stack */
static struct trace_iterator iter;
- static cpumask_t mask;
static int dump_ran;
unsigned long flags;
int cnt = 0, cpu;
@@ -3786,8 +3785,6 @@
* and then release the locks again.
*/
- cpus_clear(mask);
-
while (!trace_empty(&iter)) {
if (!cnt)
@@ -3823,19 +3820,28 @@
{
struct trace_array_cpu *data;
int i;
+ int ret = -ENOMEM;
+
+ if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
+ goto out;
+
+ if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
+ goto out_free_buffer_mask;
+
+ cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
+ cpumask_copy(tracing_cpumask, cpu_all_mask);
/* TODO: make the number of buffers hot pluggable with CPUS */
- tracing_buffer_mask = cpu_possible_map;
-
global_trace.buffer = ring_buffer_alloc(trace_buf_size,
TRACE_BUFFER_FLAGS);
if (!global_trace.buffer) {
printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
WARN_ON(1);
- return 0;
+ goto out_free_cpumask;
}
global_trace.entries = ring_buffer_size(global_trace.buffer);
+
#ifdef CONFIG_TRACER_MAX_TRACE
max_tr.buffer = ring_buffer_alloc(trace_buf_size,
TRACE_BUFFER_FLAGS);
@@ -3843,7 +3849,7 @@
printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
WARN_ON(1);
ring_buffer_free(global_trace.buffer);
- return 0;
+ goto out_free_cpumask;
}
max_tr.entries = ring_buffer_size(max_tr.buffer);
WARN_ON(max_tr.entries != global_trace.entries);
@@ -3873,8 +3879,14 @@
&trace_panic_notifier);
register_die_notifier(&trace_die_notifier);
+ ret = 0;
- return 0;
+out_free_cpumask:
+ free_cpumask_var(tracing_cpumask);
+out_free_buffer_mask:
+ free_cpumask_var(tracing_buffer_mask);
+out:
+ return ret;
}
early_initcall(tracer_alloc_buffers);
fs_initcall(tracer_init_debugfs);