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authorMaxime Ripard <maxime.ripard@free-electrons.com>2013-04-08 21:39:22 +0200
committerMaxime Ripard <maxime.ripard@free-electrons.com>2013-04-08 21:39:22 +0200
commit7c91d302ffe2ffac813c47d6ba2e7489a2ccb35f (patch)
tree78a2cf601e986694765b28079bf749a8eaa6a2b9 /kernel/trace/trace.c
parent0b824f8dad9fdfc7c1bf9c1d3ac744075eb73ec6 (diff)
parent918d7f6f68620e0721bb31402ebf87e15f826831 (diff)
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Merge remote-tracking branch 'clk/clk-for-3.10' into sunxi/core-for-3.10
Diffstat (limited to 'kernel/trace/trace.c')
-rw-r--r--kernel/trace/trace.c27
1 files changed, 24 insertions, 3 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c2e2c2310374..1f835a83cb2c 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2400,6 +2400,27 @@ static void test_ftrace_alive(struct seq_file *m)
seq_printf(m, "# MAY BE MISSING FUNCTION EVENTS\n");
}
+#ifdef CONFIG_TRACER_MAX_TRACE
+static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
+{
+ if (iter->trace->allocated_snapshot)
+ seq_printf(m, "#\n# * Snapshot is allocated *\n#\n");
+ else
+ seq_printf(m, "#\n# * Snapshot is freed *\n#\n");
+
+ seq_printf(m, "# Snapshot commands:\n");
+ seq_printf(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n");
+ seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
+ seq_printf(m, "# Takes a snapshot of the main buffer.\n");
+ seq_printf(m, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)\n");
+ seq_printf(m, "# (Doesn't have to be '2' works with any number that\n");
+ seq_printf(m, "# is not a '0' or '1')\n");
+}
+#else
+/* Should never be called */
+static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
+#endif
+
static int s_show(struct seq_file *m, void *v)
{
struct trace_iterator *iter = v;
@@ -2411,7 +2432,9 @@ static int s_show(struct seq_file *m, void *v)
seq_puts(m, "#\n");
test_ftrace_alive(m);
}
- if (iter->trace && iter->trace->print_header)
+ if (iter->snapshot && trace_empty(iter))
+ print_snapshot_help(m, iter);
+ else if (iter->trace && iter->trace->print_header)
iter->trace->print_header(m);
else
trace_default_header(m);
@@ -4144,8 +4167,6 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
default:
if (current_trace->allocated_snapshot)
tracing_reset_online_cpus(&max_tr);
- else
- ret = -EINVAL;
break;
}