Commit 36dfe925 authored by Ingo Molnar's avatar Ingo Molnar Committed by Thomas Gleixner
Browse files

ftrace: make use of tracing_cpumask



Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent c7078de1
......@@ -70,23 +70,6 @@ static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
unsigned long trace_flags = TRACE_ITER_PRINT_PARENT;
/*
* Only trace on a CPU if the bitmask is set:
*/
static cpumask_t tracing_cpumask __read_mostly = CPU_MASK_ALL;
/*
* The tracer itself will not take this lock, but still we want
* to provide a consistent cpumask to user-space:
*/
static DEFINE_MUTEX(tracing_cpumask_update_lock);
/*
* Temporary storage for the character representation of the
* CPU bitmask:
*/
static char mask_str[NR_CPUS];
void trace_wake_up(void)
{
/*
......@@ -1776,19 +1759,46 @@ static struct file_operations show_traces_fops = {
.release = seq_release,
};
/*
* 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;
/*
* The tracer itself will not take this lock, but still we want
* to provide a consistent cpumask to user-space:
*/
static DEFINE_MUTEX(tracing_cpumask_update_lock);
/*
* Temporary storage for the character representation of the
* CPU bitmask (and one more byte for the newline):
*/
static char mask_str[NR_CPUS + 1];
static ssize_t
tracing_cpumask_read(struct file *filp, char __user *ubuf,
size_t count, loff_t *ppos)
{
int err;
count = min(count, (size_t)NR_CPUS);
int len;
mutex_lock(&tracing_cpumask_update_lock);
cpumask_scnprintf(mask_str, NR_CPUS, tracing_cpumask);
err = copy_to_user(ubuf, mask_str, count);
if (err)
count = -EFAULT;
len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
if (count - len < 2) {
count = -EINVAL;
goto out_err;
}
len += sprintf(mask_str + len, "\n");
count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
out_err:
mutex_unlock(&tracing_cpumask_update_lock);
return count;
......@@ -1798,16 +1808,40 @@ static ssize_t
tracing_cpumask_write(struct file *filp, const char __user *ubuf,
size_t count, loff_t *ppos)
{
int err;
int err, cpu;
mutex_lock(&tracing_cpumask_update_lock);
err = cpumask_parse_user(ubuf, count, tracing_cpumask);
mutex_unlock(&tracing_cpumask_update_lock);
err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
if (err)
return err;
goto err_unlock;
spin_lock_irq(&ftrace_max_lock);
for_each_possible_cpu(cpu) {
/*
* 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)) {
atomic_inc(&global_trace.data[cpu]->disabled);
}
if (!cpu_isset(cpu, tracing_cpumask) &&
cpu_isset(cpu, tracing_cpumask_new)) {
atomic_dec(&global_trace.data[cpu]->disabled);
}
}
spin_unlock_irq(&ftrace_max_lock);
tracing_cpumask = tracing_cpumask_new;
mutex_unlock(&tracing_cpumask_update_lock);
return count;
err_unlock:
mutex_unlock(&tracing_cpumask_update_lock);
return err;
}
static struct file_operations tracing_cpumask_fops = {
......@@ -1846,8 +1880,7 @@ tracing_iter_ctrl_read(struct file *filp, char __user *ubuf,
r += sprintf(buf + r, "\n");
WARN_ON(r >= len + 2);
r = simple_read_from_buffer(ubuf, cnt, ppos,
buf, r);
r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
kfree(buf);
......
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