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authorSoeren Sandmann Pedersen <sandmann@redhat.com>2008-05-12 21:20:49 +0200
committerThomas Gleixner <tglx@linutronix.de>2008-05-23 20:55:43 +0200
commit2a2cc8f7c4d0dfd75720867f7dc58d24f075edfc (patch)
tree58bccce0675debd5619757a45b5aba770bf32d0e /kernel/trace/trace.c
parentaeaee8a2c9cb4489f166ca0e39c568e8254faaa6 (diff)
ftrace: allow the event pipe to be polled
Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/trace/trace.c')
-rw-r--r--kernel/trace/trace.c39
1 files changed, 38 insertions, 1 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 958c4d77a67..d041578affd 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -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,
};