[PATCH] Document backtracer selection options

Signed-off-by: Andi Kleen <ak@suse.de>

diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt
index 6da24e7a56cba01c9b7af0a0e1c894667a614d75..4303e0c12476d1afb4af9c7998e46cb2ed4b7494 100644 (file)
--- a/Documentation/x86_64/boot-options.txt
+++ b/Documentation/x86_64/boot-options.txt
@@ -245,6 +245,13 @@ Debugging
                newfallback: use new unwinder but fall back to old if it gets
                        stuck (default)
 
+  call_trace=[old|both|newfallback|new]
+               old: use old inexact backtracer
+               new: use new exact dwarf2 unwinder
+               both: print entries from both
+               newfallback: use new unwinder but fall back to old if it gets
+                       stuck (default)
+
 Misc
 
   noreplacement  Don't replace instructions with more appropriate ones