ring-buffer: Add percentage of ring buffer full to wake up reader

Instead of just waiting for a page to be full before waking up a pending
reader, allow the reader to pass in a "percentage" of pages that have
content before waking up a reader. This should help keep the process of
reading the events not cause wake ups that constantly cause reading of the
buffer.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ff1c4b20cd0a..48d5eb22ff33 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1431,7 +1431,7 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
 }
 #endif /* CONFIG_TRACER_MAX_TRACE */
 
-static int wait_on_pipe(struct trace_iterator *iter, bool full)
+static int wait_on_pipe(struct trace_iterator *iter, int full)
 {
         /* Iterators are static, they should be filled or empty */
         if (trace_buffer_iter(iter, iter->cpu_file))
@@ -5693,7 +5693,7 @@ static int tracing_wait_pipe(struct file *filp)
 
                 mutex_unlock(&iter->mutex);
 
-                ret = wait_on_pipe(iter, false);
+                ret = wait_on_pipe(iter, 0);
 
                 mutex_lock(&iter->mutex);
 
@@ -6751,7 +6751,7 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
                         if ((filp->f_flags & O_NONBLOCK))
                                 return -EAGAIN;
 
-                        ret = wait_on_pipe(iter, false);
+                        ret = wait_on_pipe(iter, 0);
                         if (ret)
                                 return ret;
 
@@ -6948,7 +6948,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
                 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
                         goto out;
 
-                ret = wait_on_pipe(iter, true);
+                ret = wait_on_pipe(iter, 1);
                 if (ret)
                         goto out;