diff options
| -rw-r--r-- | kernel/trace/trace.c | 39 |
1 files changed, 38 insertions, 1 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 958c4d77a67b..d041578affd0 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, }; |