From 65f8c95e46a1827ae8bbc52a817ea308dd7d65ae Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Tue, 17 Jul 2012 14:26:15 -0700 Subject: pstore/ftrace: Convert to its own enable/disable debugfs knob With this patch we no longer reuse function tracer infrastructure, now we register our own tracer back-end via a debugfs knob. It's a bit more code, but that is the only downside. On the bright side we have: - Ability to make persistent_ram module removable (when needed, we can move ftrace_ops struct into a module). Note that persistent_ram is still not removable for other reasons, but with this patch it's just one thing less to worry about; - Pstore part is more isolated from the generic function tracer. We tried it already by registering our own tracer in available_tracers, but that way we're loosing ability to see the traces while we record them to pstore. This solution is somewhere in the middle: we only register "internal ftracer" back-end, but not the "front-end"; - When there is only pstore tracing enabled, the kernel will only write to the pstore buffer, omitting function tracer buffer (which, of course, still can be enabled via 'echo function > current_tracer'). Suggested-by: Steven Rostedt Signed-off-by: Anton Vorontsov --- Documentation/ramoops.txt | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/ramoops.txt b/Documentation/ramoops.txt index 197ad59ab9bf..69b3cac4749d 100644 --- a/Documentation/ramoops.txt +++ b/Documentation/ramoops.txt @@ -102,9 +102,7 @@ related hangs. The functions call chain log is stored in a "ftrace-ramoops" file. Here is an example of usage: # mount -t debugfs debugfs /sys/kernel/debug/ - # cd /sys/kernel/debug/tracing - # echo function > current_tracer - # echo 1 > options/func_pstore + # echo 1 > /sys/kernel/debug/pstore/record_ftrace # reboot -f [...] # mount -t pstore pstore /mnt/ -- cgit v1.2.3-58-ga151