tracing: Prevent buffer overwrite disabled for latency tracers
authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>
Thu, 14 Mar 2013 19:03:53 +0000 (15:03 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 5 Apr 2013 16:26:16 +0000 (09:26 -0700)
commitc4ecd5ed2ac30f54ae58de2f8ee36226033fb236
treec28ae73ff36de2632398695a0b838959d0905d7a
parent88d1e05fd3f0bf7aa8712da17ffae839988fe81c
tracing: Prevent buffer overwrite disabled for latency tracers

commit 613f04a0f51e6e68ac6fe571ab79da3c0a5eb4da upstream.

The latency tracers require the buffers to be in overwrite mode,
otherwise they get screwed up. Force the buffers to stay in overwrite
mode when latency tracers are enabled.

Added a flag_changed() method to the tracer structure to allow
the tracers to see what flags are being changed, and also be able
to prevent the change from happing.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Lingzhu Xiang <lxiang@redhat.com>
Reviewed-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kernel/trace/trace.c
kernel/trace/trace.h
kernel/trace/trace_irqsoff.c
kernel/trace/trace_sched_wakeup.c