ftrace: add tracing_cpumask
Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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4ac3ba41d3
commit
c7078de1aa
1 changed files with 70 additions and 8 deletions
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@ -70,6 +70,23 @@ static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
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unsigned long trace_flags = TRACE_ITER_PRINT_PARENT;
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/*
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* Only trace on a CPU if the bitmask is set:
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*/
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static cpumask_t tracing_cpumask __read_mostly = CPU_MASK_ALL;
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/*
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* The tracer itself will not take this lock, but still we want
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* to provide a consistent cpumask to user-space:
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*/
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static DEFINE_MUTEX(tracing_cpumask_update_lock);
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/*
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* Temporary storage for the character representation of the
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* CPU bitmask:
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*/
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static char mask_str[NR_CPUS];
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void trace_wake_up(void)
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{
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/*
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@ -1754,9 +1771,49 @@ static struct file_operations tracing_lt_fops = {
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};
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static struct file_operations show_traces_fops = {
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.open = show_traces_open,
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.read = seq_read,
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.release = seq_release,
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.open = show_traces_open,
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.read = seq_read,
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.release = seq_release,
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};
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static ssize_t
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tracing_cpumask_read(struct file *filp, char __user *ubuf,
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size_t count, loff_t *ppos)
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{
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int err;
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count = min(count, (size_t)NR_CPUS);
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mutex_lock(&tracing_cpumask_update_lock);
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cpumask_scnprintf(mask_str, NR_CPUS, tracing_cpumask);
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err = copy_to_user(ubuf, mask_str, count);
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if (err)
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count = -EFAULT;
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mutex_unlock(&tracing_cpumask_update_lock);
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return count;
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}
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static ssize_t
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tracing_cpumask_write(struct file *filp, const char __user *ubuf,
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size_t count, loff_t *ppos)
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{
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int err;
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mutex_lock(&tracing_cpumask_update_lock);
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err = cpumask_parse_user(ubuf, count, tracing_cpumask);
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mutex_unlock(&tracing_cpumask_update_lock);
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if (err)
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return err;
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return count;
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}
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static struct file_operations tracing_cpumask_fops = {
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.open = tracing_open_generic,
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.read = tracing_cpumask_read,
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.write = tracing_cpumask_write,
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};
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static ssize_t
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@ -1837,9 +1894,9 @@ tracing_iter_ctrl_write(struct file *filp, const char __user *ubuf,
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}
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static struct file_operations tracing_iter_fops = {
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.open = tracing_open_generic,
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.read = tracing_iter_ctrl_read,
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.write = tracing_iter_ctrl_write,
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.open = tracing_open_generic,
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.read = tracing_iter_ctrl_read,
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.write = tracing_iter_ctrl_write,
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};
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static const char readme_msg[] =
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@ -1870,8 +1927,8 @@ tracing_readme_read(struct file *filp, char __user *ubuf,
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}
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static struct file_operations tracing_readme_fops = {
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.open = tracing_open_generic,
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.read = tracing_readme_read,
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.open = tracing_open_generic,
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.read = tracing_readme_read,
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};
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static ssize_t
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@ -2334,6 +2391,11 @@ static __init void tracer_init_debugfs(void)
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if (!entry)
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pr_warning("Could not create debugfs 'iter_ctrl' entry\n");
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entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer,
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NULL, &tracing_cpumask_fops);
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if (!entry)
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pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
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entry = debugfs_create_file("latency_trace", 0444, d_tracer,
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&global_trace, &tracing_lt_fops);
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if (!entry)
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