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ftrace: Remove global function list and call function directly

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Instead of having a list of global functions that are called,
as only one global function is allow to be enabled at a time, there's
no reason to have a list.

Instead, simply have all the users of the global ops, use the global ops
directly, instead of registering their own ftrace_ops. Just switch what
function is used before enabling the function tracer.

This removes a lot of code as well as the complexity involved with it.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Red Hat)
2014-01-10 17:01:58 -05:00
committed by Steven Rostedt
parent a798c10faf
commit 4104d326b6
8 changed files with 133 additions and 221 deletions
Download Patch File Download Diff File Expand all files Collapse all files

152
kernel/trace/ftrace.c
View File

@@ -62,7 +62,7 @@
#define FTRACE_HASH_DEFAULT_BITS 10
#define FTRACE_HASH_MAX_BITS 12
#define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_CONTROL)
#define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_CONTROL)
#ifdef CONFIG_DYNAMIC_FTRACE
#define INIT_REGEX_LOCK(opsname) \
@@ -103,7 +103,6 @@ static int ftrace_disabled __read_mostly;
static DEFINE_MUTEX(ftrace_lock);
static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end;
static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
@@ -171,23 +170,6 @@ int ftrace_nr_registered_ops(void)
return cnt;
}
static void
ftrace_global_list_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs)
{
int bit;
bit = trace_test_and_set_recursion(TRACE_GLOBAL_START, TRACE_GLOBAL_MAX);
if (bit < 0)
return;
do_for_each_ftrace_op(op, ftrace_global_list) {
op->func(ip, parent_ip, op, regs);
} while_for_each_ftrace_op(op);
trace_clear_recursion(bit);
}
static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs)
{
@@ -237,43 +219,6 @@ static int control_ops_alloc(struct ftrace_ops *ops)
return 0;
}
static void update_global_ops(void)
{
ftrace_func_t func = ftrace_global_list_func;
void *private = NULL;
/* The list has its own recursion protection. */
global_ops.flags |= FTRACE_OPS_FL_RECURSION_SAFE;
/*
* If there's only one function registered, then call that
* function directly. Otherwise, we need to iterate over the
* registered callers.
*/
if (ftrace_global_list == &ftrace_list_end ||
ftrace_global_list->next == &ftrace_list_end) {
func = ftrace_global_list->func;
private = ftrace_global_list->private;
/*
* As we are calling the function directly.
* If it does not have recursion protection,
* the function_trace_op needs to be updated
* accordingly.
*/
if (!(ftrace_global_list->flags & FTRACE_OPS_FL_RECURSION_SAFE))
global_ops.flags &= ~FTRACE_OPS_FL_RECURSION_SAFE;
}
/* If we filter on pids, update to use the pid function */
if (!list_empty(&ftrace_pids)) {
set_ftrace_pid_function(func);
func = ftrace_pid_func;
}
global_ops.func = func;
global_ops.private = private;
}
static void ftrace_sync(struct work_struct *work)
{
/*
@@ -301,8 +246,6 @@ static void update_ftrace_function(void)
{
ftrace_func_t func;
update_global_ops();
/*
* If we are at the end of the list and this ops is
* recursion safe and not dynamic and the arch supports passing ops,
@@ -314,10 +257,7 @@ static void update_ftrace_function(void)
(ftrace_ops_list->flags & FTRACE_OPS_FL_RECURSION_SAFE) &&
!FTRACE_FORCE_LIST_FUNC)) {
/* Set the ftrace_ops that the arch callback uses */
if (ftrace_ops_list == &global_ops)
set_function_trace_op = ftrace_global_list;
else
set_function_trace_op = ftrace_ops_list;
set_function_trace_op = ftrace_ops_list;
func = ftrace_ops_list->func;
} else {
/* Just use the default ftrace_ops */
@@ -434,16 +374,9 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
if (ops->flags & FTRACE_OPS_FL_DELETED)
return -EINVAL;
if (FTRACE_WARN_ON(ops == &global_ops))
return -EINVAL;
if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
return -EBUSY;
/* We don't support both control and global flags set. */
if ((ops->flags & FL_GLOBAL_CONTROL_MASK) == FL_GLOBAL_CONTROL_MASK)
return -EINVAL;
#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
/*
* If the ftrace_ops specifies SAVE_REGS, then it only can be used
@@ -461,10 +394,7 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
if (!core_kernel_data((unsigned long)ops))
ops->flags |= FTRACE_OPS_FL_DYNAMIC;
if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
add_ftrace_list_ops(&ftrace_global_list, &global_ops, ops);
ops->flags |= FTRACE_OPS_FL_ENABLED;
} else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
if (ops->flags & FTRACE_OPS_FL_CONTROL) {
if (control_ops_alloc(ops))
return -ENOMEM;
add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
@@ -484,15 +414,7 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
return -EBUSY;
if (FTRACE_WARN_ON(ops == &global_ops))
return -EINVAL;
if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
ret = remove_ftrace_list_ops(&ftrace_global_list,
&global_ops, ops);
if (!ret)
ops->flags &= ~FTRACE_OPS_FL_ENABLED;
} else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
if (ops->flags & FTRACE_OPS_FL_CONTROL) {
ret = remove_ftrace_list_ops(&ftrace_control_list,
&control_ops, ops);
} else
@@ -2128,15 +2050,6 @@ static int ftrace_startup(struct ftrace_ops *ops, int command)
ftrace_start_up++;
command |= FTRACE_UPDATE_CALLS;
/* ops marked global share the filter hashes */
if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
ops = &global_ops;
/* Don't update hash if global is already set */
if (global_start_up)
hash_enable = false;
global_start_up++;
}
ops->flags |= FTRACE_OPS_FL_ENABLED;
if (hash_enable)
ftrace_hash_rec_enable(ops, 1);
@@ -2166,21 +2079,10 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command)
*/
WARN_ON_ONCE(ftrace_start_up < 0);
if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
ops = &global_ops;
global_start_up--;
WARN_ON_ONCE(global_start_up < 0);
/* Don't update hash if global still has users */
if (global_start_up) {
WARN_ON_ONCE(!ftrace_start_up);
hash_disable = false;
}
}
if (hash_disable)
ftrace_hash_rec_disable(ops, 1);
if (ops != &global_ops || !global_start_up)
if (!global_start_up)
ops->flags &= ~FTRACE_OPS_FL_ENABLED;
command |= FTRACE_UPDATE_CALLS;
@@ -3524,10 +3426,6 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
struct ftrace_hash *hash;
int ret;
/* All global ops uses the global ops filters */
if (ops->flags & FTRACE_OPS_FL_GLOBAL)
ops = &global_ops;
if (unlikely(ftrace_disabled))
return -ENODEV;
@@ -4462,6 +4360,34 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
#endif /* CONFIG_DYNAMIC_FTRACE */
__init void ftrace_init_global_array_ops(struct trace_array *tr)
{
tr->ops = &global_ops;
tr->ops->private = tr;
}
void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
{
/* If we filter on pids, update to use the pid function */
if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
if (WARN_ON(tr->ops->func != ftrace_stub))
printk("ftrace ops had %pS for function\n",
tr->ops->func);
/* Only the top level instance does pid tracing */
if (!list_empty(&ftrace_pids)) {
set_ftrace_pid_function(func);
func = ftrace_pid_func;
}
}
tr->ops->func = func;
tr->ops->private = tr;
}
void ftrace_reset_array_ops(struct trace_array *tr)
{
tr->ops->func = ftrace_stub;
}
static void
ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs)
@@ -4520,9 +4446,16 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
*/
preempt_disable_notrace();
do_for_each_ftrace_op(op, ftrace_ops_list) {
if (ftrace_ops_test(op, ip, regs))
if (ftrace_ops_test(op, ip, regs)) {
if (WARN_ON(!op->func)) {
function_trace_stop = 1;
printk("op=%p %pS\n", op, op);
goto out;
}
op->func(ip, parent_ip, op, regs);
}
} while_for_each_ftrace_op(op);
out:
preempt_enable_notrace();
trace_clear_recursion(bit);
}
@@ -5076,8 +5009,7 @@ ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
/* Just a place holder for function graph */
static struct ftrace_ops fgraph_ops __read_mostly = {
.func = ftrace_stub,
.flags = FTRACE_OPS_FL_STUB | FTRACE_OPS_FL_GLOBAL |
FTRACE_OPS_FL_RECURSION_SAFE,
.flags = FTRACE_OPS_FL_STUB | FTRACE_OPS_FL_RECURSION_SAFE,
};
static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)