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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2013-03-14 20:03:53 +0100
committerSteven Rostedt <rostedt@goodmis.org>2013-03-15 04:40:21 +0100
commit613f04a0f51e6e68ac6fe571ab79da3c0a5eb4da (patch)
tree2bc6da65edff6669f68010a22595861af26fe44d /kernel/trace/trace.h
parenttracing: Keep overwrite in sync between regular and snapshot buffers (diff)
downloadlinux-613f04a0f51e6e68ac6fe571ab79da3c0a5eb4da.tar.xz
linux-613f04a0f51e6e68ac6fe571ab79da3c0a5eb4da.zip
tracing: Prevent buffer overwrite disabled for latency tracers
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. Cc: stable@vger.kernel.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace.h')
-rw-r--r--kernel/trace/trace.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 57d7e5397d56..2081971367ea 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -283,11 +283,15 @@ struct tracer {
enum print_line_t (*print_line)(struct trace_iterator *iter);
/* If you handled the flag setting, return 0 */
int (*set_flag)(u32 old_flags, u32 bit, int set);
+ /* Return 0 if OK with change, else return non-zero */
+ int (*flag_changed)(struct tracer *tracer,
+ u32 mask, int set);
struct tracer *next;
struct tracer_flags *flags;
bool print_max;
bool use_max_tr;
bool allocated_snapshot;
+ bool enabled;
};
@@ -943,6 +947,8 @@ extern const char *__stop___trace_bprintk_fmt[];
void trace_printk_init_buffers(void);
void trace_printk_start_comm(void);
+int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set);
+int set_tracer_flag(unsigned int mask, int enabled);
#undef FTRACE_ENTRY
#define FTRACE_ENTRY(call, struct_name, id, tstruct, print, filter) \