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| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2019-11-08 19:12:57 +0100 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2019-11-13 15:36:49 +0100 |
| commit | a3ad1a7e39689005cb04a4f2adb82f9d55b4724f (patch) | |
| tree | 64deafb73e244d233836735dd2fa6a3c41462cc6 /kernel/trace | |
| parent | ftrace/x86: Add register_ftrace_direct() for custom trampolines (diff) | |
| download | linux-a3ad1a7e39689005cb04a4f2adb82f9d55b4724f.tar.xz linux-a3ad1a7e39689005cb04a4f2adb82f9d55b4724f.zip | |
ftrace/x86: Add a counter to test function_graph with direct
As testing for direct calls from the function graph tracer adds a little
overhead (which is a lot when tracing every function), add a counter that
can be used to test if function_graph tracer needs to test for a direct
caller or not.
It would have been nicer if we could use a static branch, but the static
branch logic fails when used within the function graph tracer trampoline.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/ftrace.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index c4446eabacbe..f9456346ec66 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2364,6 +2364,7 @@ ftrace_find_tramp_ops_new(struct dyn_ftrace *rec) /* Protected by rcu_tasks for reading, and direct_mutex for writing */ static struct ftrace_hash *direct_functions = EMPTY_HASH; static DEFINE_MUTEX(direct_mutex); +int ftrace_direct_func_count; /* * Search the direct_functions hash to see if the given instruction pointer @@ -5056,6 +5057,7 @@ int register_ftrace_direct(unsigned long ip, unsigned long addr) direct->addr = addr; direct->count = 0; list_add_rcu(&direct->next, &ftrace_direct_funcs); + ftrace_direct_func_count++; } entry->ip = ip; @@ -5081,6 +5083,7 @@ int register_ftrace_direct(unsigned long ip, unsigned long addr) if (free_hash) free_ftrace_hash(free_hash); free_hash = NULL; + ftrace_direct_func_count--; } } else { if (!direct->count) @@ -5141,6 +5144,7 @@ int unregister_ftrace_direct(unsigned long ip, unsigned long addr) list_del_rcu(&direct->next); synchronize_rcu_tasks(); kfree(direct); + ftrace_direct_func_count--; } } out_unlock: |