[for-next][PATCH 05/12] ftrace: Have set_ftrace_pid use the bitmap like events do
From: Steven Rostedt
Date: Sun Jul 03 2016 - 16:35:27 EST
From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx>
Convert set_ftrace_pid to use the bitmap like set_event_pid does. This
allows for instances to use the pid filtering as well, and will allow for
function-fork option to set if the children of a traced function should be
traced or not.
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/ftrace.c | 313 +++++++++++++++--------------------
kernel/trace/trace.c | 1 +
kernel/trace/trace.h | 15 +-
kernel/trace/trace_functions.c | 2 +-
kernel/trace/trace_functions_graph.c | 2 +-
5 files changed, 148 insertions(+), 185 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 900dbb1efff2..8b488f4dd8e8 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -89,16 +89,16 @@ struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
/* What to set function_trace_op to */
static struct ftrace_ops *set_function_trace_op;
-/* List for set_ftrace_pid's pids. */
-LIST_HEAD(ftrace_pids);
-struct ftrace_pid {
- struct list_head list;
- struct pid *pid;
-};
-
-static bool ftrace_pids_enabled(void)
+static bool ftrace_pids_enabled(struct ftrace_ops *ops)
{
- return !list_empty(&ftrace_pids);
+ struct trace_array *tr;
+
+ if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
+ return false;
+
+ tr = ops->private;
+
+ return tr->function_pids != NULL;
}
static void ftrace_update_trampoline(struct ftrace_ops *ops);
@@ -179,7 +179,9 @@ int ftrace_nr_registered_ops(void)
static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs)
{
- if (!test_tsk_trace_trace(current))
+ struct trace_array *tr = op->private;
+
+ if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid))
return;
op->saved_func(ip, parent_ip, op, regs);
@@ -417,7 +419,7 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
/* Always save the function, and reset at unregistering */
ops->saved_func = ops->func;
- if (ops->flags & FTRACE_OPS_FL_PID && ftrace_pids_enabled())
+ if (ftrace_pids_enabled(ops))
ops->func = ftrace_pid_func;
ftrace_update_trampoline(ops);
@@ -450,7 +452,6 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
static void ftrace_update_pid_func(void)
{
- bool enabled = ftrace_pids_enabled();
struct ftrace_ops *op;
/* Only do something if we are tracing something */
@@ -459,8 +460,8 @@ static void ftrace_update_pid_func(void)
do_for_each_ftrace_op(op, ftrace_ops_list) {
if (op->flags & FTRACE_OPS_FL_PID) {
- op->func = enabled ? ftrace_pid_func :
- op->saved_func;
+ op->func = ftrace_pids_enabled(op) ?
+ ftrace_pid_func : op->saved_func;
ftrace_update_trampoline(op);
}
} while_for_each_ftrace_op(op);
@@ -5324,179 +5325,99 @@ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
return ops->func;
}
-static void clear_ftrace_swapper(void)
+static void
+ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
+ struct task_struct *prev, struct task_struct *next)
{
- struct task_struct *p;
- int cpu;
+ struct trace_array *tr = data;
+ struct trace_pid_list *pid_list;
- get_online_cpus();
- for_each_online_cpu(cpu) {
- p = idle_task(cpu);
- clear_tsk_trace_trace(p);
- }
- put_online_cpus();
-}
-
-static void set_ftrace_swapper(void)
-{
- struct task_struct *p;
- int cpu;
+ pid_list = rcu_dereference_sched(tr->function_pids);
- get_online_cpus();
- for_each_online_cpu(cpu) {
- p = idle_task(cpu);
- set_tsk_trace_trace(p);
- }
- put_online_cpus();
+ this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
+ trace_ignore_this_task(pid_list, next));
}
-static void clear_ftrace_pid(struct pid *pid)
+static void clear_ftrace_pids(struct trace_array *tr)
{
- struct task_struct *p;
+ struct trace_pid_list *pid_list;
+ int cpu;
- rcu_read_lock();
- do_each_pid_task(pid, PIDTYPE_PID, p) {
- clear_tsk_trace_trace(p);
- } while_each_pid_task(pid, PIDTYPE_PID, p);
- rcu_read_unlock();
+ pid_list = rcu_dereference_protected(tr->function_pids,
+ lockdep_is_held(&ftrace_lock));
+ if (!pid_list)
+ return;
- put_pid(pid);
-}
+ unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
-static void set_ftrace_pid(struct pid *pid)
-{
- struct task_struct *p;
+ for_each_possible_cpu(cpu)
+ per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false;
- rcu_read_lock();
- do_each_pid_task(pid, PIDTYPE_PID, p) {
- set_tsk_trace_trace(p);
- } while_each_pid_task(pid, PIDTYPE_PID, p);
- rcu_read_unlock();
-}
+ rcu_assign_pointer(tr->function_pids, NULL);
-static void clear_ftrace_pid_task(struct pid *pid)
-{
- if (pid == ftrace_swapper_pid)
- clear_ftrace_swapper();
- else
- clear_ftrace_pid(pid);
-}
+ /* Wait till all users are no longer using pid filtering */
+ synchronize_sched();
-static void set_ftrace_pid_task(struct pid *pid)
-{
- if (pid == ftrace_swapper_pid)
- set_ftrace_swapper();
- else
- set_ftrace_pid(pid);
+ trace_free_pid_list(pid_list);
}
-static int ftrace_pid_add(int p)
+static void ftrace_pid_reset(struct trace_array *tr)
{
- struct pid *pid;
- struct ftrace_pid *fpid;
- int ret = -EINVAL;
-
mutex_lock(&ftrace_lock);
-
- if (!p)
- pid = ftrace_swapper_pid;
- else
- pid = find_get_pid(p);
-
- if (!pid)
- goto out;
-
- ret = 0;
-
- list_for_each_entry(fpid, &ftrace_pids, list)
- if (fpid->pid == pid)
- goto out_put;
-
- ret = -ENOMEM;
-
- fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
- if (!fpid)
- goto out_put;
-
- list_add(&fpid->list, &ftrace_pids);
- fpid->pid = pid;
-
- set_ftrace_pid_task(pid);
+ clear_ftrace_pids(tr);
ftrace_update_pid_func();
-
ftrace_startup_all(0);
mutex_unlock(&ftrace_lock);
- return 0;
-
-out_put:
- if (pid != ftrace_swapper_pid)
- put_pid(pid);
-
-out:
- mutex_unlock(&ftrace_lock);
- return ret;
}
-static void ftrace_pid_reset(void)
-{
- struct ftrace_pid *fpid, *safe;
-
- mutex_lock(&ftrace_lock);
- list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
- struct pid *pid = fpid->pid;
-
- clear_ftrace_pid_task(pid);
-
- list_del(&fpid->list);
- kfree(fpid);
- }
-
- ftrace_update_pid_func();
- ftrace_startup_all(0);
-
- mutex_unlock(&ftrace_lock);
-}
+/* Greater than any max PID */
+#define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
static void *fpid_start(struct seq_file *m, loff_t *pos)
+ __acquires(RCU)
{
+ struct trace_pid_list *pid_list;
+ struct trace_array *tr = m->private;
+
mutex_lock(&ftrace_lock);
+ rcu_read_lock_sched();
- if (!ftrace_pids_enabled() && (!*pos))
- return (void *) 1;
+ pid_list = rcu_dereference_sched(tr->function_pids);
- return seq_list_start(&ftrace_pids, *pos);
+ if (!pid_list)
+ return !(*pos) ? FTRACE_NO_PIDS : NULL;
+
+ return trace_pid_start(pid_list, pos);
}
static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
{
- if (v == (void *)1)
+ struct trace_array *tr = m->private;
+ struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
+
+ if (v == FTRACE_NO_PIDS)
return NULL;
- return seq_list_next(v, &ftrace_pids, pos);
+ return trace_pid_next(pid_list, v, pos);
}
static void fpid_stop(struct seq_file *m, void *p)
+ __releases(RCU)
{
+ rcu_read_unlock_sched();
mutex_unlock(&ftrace_lock);
}
static int fpid_show(struct seq_file *m, void *v)
{
- const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
-
- if (v == (void *)1) {
+ if (v == FTRACE_NO_PIDS) {
seq_puts(m, "no pid\n");
return 0;
}
- if (fpid->pid == ftrace_swapper_pid)
- seq_puts(m, "swapper tasks\n");
- else
- seq_printf(m, "%u\n", pid_vnr(fpid->pid));
-
- return 0;
+ return trace_pid_show(m, v);
}
static const struct seq_operations ftrace_pid_sops = {
@@ -5509,58 +5430,103 @@ static const struct seq_operations ftrace_pid_sops = {
static int
ftrace_pid_open(struct inode *inode, struct file *file)
{
+ struct trace_array *tr = inode->i_private;
+ struct seq_file *m;
int ret = 0;
+ if (trace_array_get(tr) < 0)
+ return -ENODEV;
+
if ((file->f_mode & FMODE_WRITE) &&
(file->f_flags & O_TRUNC))
- ftrace_pid_reset();
+ ftrace_pid_reset(tr);
- if (file->f_mode & FMODE_READ)
- ret = seq_open(file, &ftrace_pid_sops);
+ ret = seq_open(file, &ftrace_pid_sops);
+ if (ret < 0) {
+ trace_array_put(tr);
+ } else {
+ m = file->private_data;
+ /* copy tr over to seq ops */
+ m->private = tr;
+ }
return ret;
}
+static void ignore_task_cpu(void *data)
+{
+ struct trace_array *tr = data;
+ struct trace_pid_list *pid_list;
+
+ /*
+ * This function is called by on_each_cpu() while the
+ * event_mutex is held.
+ */
+ pid_list = rcu_dereference_protected(tr->function_pids,
+ mutex_is_locked(&ftrace_lock));
+
+ this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
+ trace_ignore_this_task(pid_list, current));
+}
+
static ssize_t
ftrace_pid_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
- char buf[64], *tmp;
- long val;
- int ret;
+ struct seq_file *m = filp->private_data;
+ struct trace_array *tr = m->private;
+ struct trace_pid_list *filtered_pids = NULL;
+ struct trace_pid_list *pid_list;
+ ssize_t ret;
- if (cnt >= sizeof(buf))
- return -EINVAL;
+ if (!cnt)
+ return 0;
+
+ mutex_lock(&ftrace_lock);
+
+ filtered_pids = rcu_dereference_protected(tr->function_pids,
+ lockdep_is_held(&ftrace_lock));
+
+ ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
+ if (ret < 0)
+ goto out;
- if (copy_from_user(&buf, ubuf, cnt))
- return -EFAULT;
+ rcu_assign_pointer(tr->function_pids, pid_list);
- buf[cnt] = 0;
+ if (filtered_pids) {
+ synchronize_sched();
+ trace_free_pid_list(filtered_pids);
+ } else if (pid_list) {
+ /* Register a probe to set whether to ignore the tracing of a task */
+ register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
+ }
/*
- * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
- * to clean the filter quietly.
+ * Ignoring of pids is done at task switch. But we have to
+ * check for those tasks that are currently running.
+ * Always do this in case a pid was appended or removed.
*/
- tmp = strstrip(buf);
- if (strlen(tmp) == 0)
- return 1;
+ on_each_cpu(ignore_task_cpu, tr, 1);
- ret = kstrtol(tmp, 10, &val);
- if (ret < 0)
- return ret;
+ ftrace_update_pid_func();
+ ftrace_startup_all(0);
+ out:
+ mutex_unlock(&ftrace_lock);
- ret = ftrace_pid_add(val);
+ if (ret > 0)
+ *ppos += ret;
- return ret ? ret : cnt;
+ return ret;
}
static int
ftrace_pid_release(struct inode *inode, struct file *file)
{
- if (file->f_mode & FMODE_READ)
- seq_release(inode, file);
+ struct trace_array *tr = inode->i_private;
- return 0;
+ trace_array_put(tr);
+
+ return seq_release(inode, file);
}
static const struct file_operations ftrace_pid_fops = {
@@ -5571,24 +5537,17 @@ static const struct file_operations ftrace_pid_fops = {
.release = ftrace_pid_release,
};
-static __init int ftrace_init_tracefs(void)
+void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
{
- struct dentry *d_tracer;
-
- d_tracer = tracing_init_dentry();
- if (IS_ERR(d_tracer))
- return 0;
-
- ftrace_init_dyn_tracefs(d_tracer);
+ /* Only the top level directory has the dyn_tracefs and profile */
+ if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
+ ftrace_init_dyn_tracefs(d_tracer);
+ ftrace_profile_tracefs(d_tracer);
+ }
trace_create_file("set_ftrace_pid", 0644, d_tracer,
- NULL, &ftrace_pid_fops);
-
- ftrace_profile_tracefs(d_tracer);
-
- return 0;
+ tr, &ftrace_pid_fops);
}
-fs_initcall(ftrace_init_tracefs);
/**
* ftrace_kill - kill ftrace
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a8bb7485fd1d..aa240551fc5d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -7233,6 +7233,7 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
for_each_tracing_cpu(cpu)
tracing_init_tracefs_percpu(tr, cpu);
+ ftrace_init_tracefs(tr, d_tracer);
}
static struct vfsmount *trace_automount(void *ingore)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index a4dce1ef9e03..eaee458755a4 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -156,6 +156,9 @@ struct trace_array_cpu {
char comm[TASK_COMM_LEN];
bool ignore_pid;
+#ifdef CONFIG_FUNCTION_TRACER
+ bool ftrace_ignore_pid;
+#endif
};
struct tracer;
@@ -247,6 +250,7 @@ struct trace_array {
int ref;
#ifdef CONFIG_FUNCTION_TRACER
struct ftrace_ops *ops;
+ struct trace_pid_list __rcu *function_pids;
/* function tracing enabled */
int function_enabled;
#endif
@@ -840,12 +844,9 @@ extern struct list_head ftrace_pids;
#ifdef CONFIG_FUNCTION_TRACER
extern bool ftrace_filter_param __initdata;
-static inline int ftrace_trace_task(struct task_struct *task)
+static inline int ftrace_trace_task(struct trace_array *tr)
{
- if (list_empty(&ftrace_pids))
- return 1;
-
- return test_tsk_trace_trace(task);
+ return !this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid);
}
extern int ftrace_is_dead(void);
int ftrace_create_function_files(struct trace_array *tr,
@@ -855,8 +856,9 @@ void ftrace_init_global_array_ops(struct trace_array *tr);
void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func);
void ftrace_reset_array_ops(struct trace_array *tr);
int using_ftrace_ops_list_func(void);
+void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer);
#else
-static inline int ftrace_trace_task(struct task_struct *task)
+static inline int ftrace_trace_task(struct trace_array *tr)
{
return 1;
}
@@ -871,6 +873,7 @@ static inline void ftrace_destroy_function_files(struct trace_array *tr) { }
static inline __init void
ftrace_init_global_array_ops(struct trace_array *tr) { }
static inline void ftrace_reset_array_ops(struct trace_array *tr) { }
+static inline void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d) { }
/* ftace_func_t type is not defined, use macro instead of static inline */
#define ftrace_init_array_ops(tr, func) do { } while (0)
#endif /* CONFIG_FUNCTION_TRACER */
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 5a095c2e4b69..0efa00d80623 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -43,7 +43,7 @@ static int allocate_ftrace_ops(struct trace_array *tr)
/* Currently only the non stack verision is supported */
ops->func = function_trace_call;
- ops->flags = FTRACE_OPS_FL_RECURSION_SAFE;
+ ops->flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_PID;
tr->ops = ops;
ops->private = tr;
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 3a0244ff7ea8..67cce7896aeb 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -319,7 +319,7 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
int cpu;
int pc;
- if (!ftrace_trace_task(current))
+ if (!ftrace_trace_task(tr))
return 0;
/* trace it when it is-nested-in or is a function enabled. */
--
2.8.1