1 files changed, 53 insertions, 1 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 48d5eb22ff33..d382fd1aa4a6 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -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, 1);
+                ret = wait_on_pipe(iter, iter->tr->buffer_percent);
                 if (ret)
                         goto out;
 
@@ -7662,6 +7662,53 @@ static const struct file_operations rb_simple_fops = {
         .llseek         = default_llseek,
 };
 
+static ssize_t
+buffer_percent_read(struct file *filp, char __user *ubuf,
+                    size_t cnt, loff_t *ppos)
+{
+        struct trace_array *tr = filp->private_data;
+        char buf[64];
+        int r;
+
+        r = tr->buffer_percent;
+        r = sprintf(buf, "%d\n", r);
+
+        return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+buffer_percent_write(struct file *filp, const char __user *ubuf,
+                     size_t cnt, loff_t *ppos)
+{
+        struct trace_array *tr = filp->private_data;
+        unsigned long val;
+        int ret;
+
+        ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+        if (ret)
+                return ret;
+
+        if (val > 100)
+                return -EINVAL;
+
+        if (!val)
+                val = 1;
+
+        tr->buffer_percent = val;
+
+        (*ppos)++;
+
+        return cnt;
+}
+
+static const struct file_operations buffer_percent_fops = {
+        .open           = tracing_open_generic_tr,
+        .read           = buffer_percent_read,
+        .write          = buffer_percent_write,
+        .release        = tracing_release_generic_tr,
+        .llseek         = default_llseek,
+};
+
 struct dentry *trace_instance_dir;
 
 static void
@@ -7970,6 +8017,11 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
         trace_create_file("timestamp_mode", 0444, d_tracer, tr,
                           &trace_time_stamp_mode_fops);
 
+        tr->buffer_percent = 1;
+
+        trace_create_file("buffer_percent", 0444, d_tracer,
+                        tr, &buffer_percent_fops);
+
         create_trace_options_dir(tr);
 
 #if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)