tracing: Add the constant count for branch tracer

The unlikely/likely branch profiler now gets called even if the if statement
is a constant (always goes in one direction without a compare). Add a value
to denote this in the likely/unlikely tracer as well.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index fd483d7..4d8fdf3 100644 (file)
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -27,7 +27,7 @@ static DEFINE_MUTEX(branch_tracing_mutex);
 static struct trace_array *branch_tracer;
 
 static void
-probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
+probe_likely_condition(struct ftrace_likely_data *f, int val, int expect)
 {
        struct trace_event_call *call = &event_branch;
        struct trace_array *tr = branch_tracer;
@@ -68,16 +68,17 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
        entry   = ring_buffer_event_data(event);
 
        /* Strip off the path, only save the file */
-       p = f->file + strlen(f->file);
-       while (p >= f->file && *p != '/')
+       p = f->data.file + strlen(f->data.file);
+       while (p >= f->data.file && *p != '/')
                p--;
        p++;
 
-       strncpy(entry->func, f->func, TRACE_FUNC_SIZE);
+       strncpy(entry->func, f->data.func, TRACE_FUNC_SIZE);
        strncpy(entry->file, p, TRACE_FILE_SIZE);
        entry->func[TRACE_FUNC_SIZE] = 0;
        entry->file[TRACE_FILE_SIZE] = 0;
-       entry->line = f->line;
+       entry->constant = f->constant;
+       entry->line = f->data.line;
        entry->correct = val == expect;
 
        if (!call_filter_check_discard(call, entry, buffer, event))
@@ -89,7 +90,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
 }
 
 static inline
-void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)
+void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)
 {
        if (!branch_tracing_enabled)
                return;
@@ -195,7 +196,7 @@ core_initcall(init_branch_tracer);
 
 #else
 static inline
-void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)
+void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)
 {
 }
 #endif /* CONFIG_BRANCH_TRACER */
@@ -214,7 +215,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
         * conditions that the recursive nightmare that exists is too
         * much to try to get working. At least for now.
         */
-       trace_likely_condition(&f->data, val, expect);
+       trace_likely_condition(f, val, expect);
 
        /* FIXME: Make this atomic! */
        if (val == expect)

diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
index eb7396b..c203ac4 100644 (file)
--- a/kernel/trace/trace_entries.h
+++ b/kernel/trace/trace_entries.h
@@ -328,11 +328,13 @@ FTRACE_ENTRY(branch, trace_branch,
                __array(        char,           func,   TRACE_FUNC_SIZE+1       )
                __array(        char,           file,   TRACE_FILE_SIZE+1       )
                __field(        char,           correct                         )
+               __field(        char,           constant                        )
        ),
 
-       F_printk("%u:%s:%s (%u)",
+       F_printk("%u:%s:%s (%u)%s",
                 __entry->line,
-                __entry->func, __entry->file, __entry->correct),
+                __entry->func, __entry->file, __entry->correct,
+                __entry->constant ? " CONSTANT" : ""),
 
        FILTER_OTHER
 );