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ftrace: allow the event pipe to be polled

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Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Soeren Sandmann Pedersen 2008-05-12 21:20:49 +02:00 committed by Thomas Gleixner
parent aeaee8a2c9
commit 2a2cc8f7c4
1 changed files with 38 additions and 1 deletions
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39
kernel/trace/trace.c
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@ -24,6 +24,7 @@
#include <linux/percpu.h>
#include <linux/ctype.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/gfp.h>
#include <linux/fs.h>
@ -63,6 +64,7 @@ static struct tracer *current_trace __read_mostly;
static int max_tracer_type_len;
static DEFINE_MUTEX(trace_types_lock);
static DECLARE_WAIT_QUEUE_HEAD (trace_wait);
#define ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(struct trace_entry))
@ -105,6 +107,7 @@ enum trace_iterator_flags {
TRACE_ITER_RAW = 0x10,
TRACE_ITER_HEX = 0x20,
TRACE_ITER_BIN = 0x40,
TRACE_ITER_BLOCK = 0x80,
};
#define TRACE_ITER_SYM_MASK \
@ -119,6 +122,7 @@ static const char *trace_options[] = {
"raw",
"hex",
"bin",
"block",
NULL
};
@ -650,6 +654,9 @@ __ftrace(struct trace_array *tr, struct trace_array_cpu *data,
entry->fn.ip = ip;
entry->fn.parent_ip = parent_ip;
spin_unlock_irqrestore(&data->lock, irq_flags);
if (!(trace_flags & TRACE_ITER_BLOCK))
wake_up (&trace_wait);
}
notrace void
@ -675,6 +682,9 @@ trace_special(struct trace_array *tr, struct trace_array_cpu *data,
entry->special.arg2 = arg2;
entry->special.arg3 = arg3;
spin_unlock_irqrestore(&data->lock, irq_flags);
if (!(trace_flags & TRACE_ITER_BLOCK))
wake_up (&trace_wait);
}
notrace void
@ -696,6 +706,9 @@ tracing_sched_switch_trace(struct trace_array *tr,
entry->ctx.next_pid = next->pid;
entry->ctx.next_prio = next->prio;
spin_unlock_irqrestore(&data->lock, irq_flags);
if (!(trace_flags & TRACE_ITER_BLOCK))
wake_up (&trace_wait);
}
#ifdef CONFIG_FTRACE
@ -1765,7 +1778,6 @@ static struct file_operations tracing_readme_fops = {
.read = tracing_readme_read,
};
static ssize_t
tracing_ctrl_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
@ -1953,6 +1965,28 @@ static int tracing_release_pipe(struct inode *inode, struct file *file)
return 0;
}
static unsigned int
tracing_poll_pipe(struct file *filp, poll_table *poll_table)
{
struct trace_iterator *iter = filp->private_data;
if (trace_flags & TRACE_ITER_BLOCK) {
/*
* Always select as readable when in blocking mode
*/
return POLLIN | POLLRDNORM;
}
else {
if (!trace_empty(iter))
return POLLIN | POLLRDNORM;
poll_wait(filp, &trace_wait, poll_table);
if (!trace_empty(iter))
return POLLIN | POLLRDNORM;
return 0;
}
}
/*
* Consumer reader.
*/
@ -1991,6 +2025,8 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
start = 0;
while (trace_empty(iter)) {
if (!(trace_flags & TRACE_ITER_BLOCK))
return -EWOULDBLOCK;
/*
* This is a make-shift waitqueue. The reason we don't use
* an actual wait queue is because:
@ -2134,6 +2170,7 @@ static struct file_operations set_tracer_fops = {
static struct file_operations tracing_pipe_fops = {
.open = tracing_open_pipe,
.poll = tracing_poll_pipe,
.read = tracing_read_pipe,
.release = tracing_release_pipe,
};