A trace instance may only need to enable specific events. As the eventfs
directory of an instance currently creates all events which adds overhead,
allow internal instances to be created with just the events in systems
that they care about. This currently only deals with systems and not
individual events, but this should bring down the overhead of creating
instances for specific use cases quite bit.
The trace_array_get_by_name() now has another parameter "systems". This
parameter is a const string pointer of a comma/space separated list of
event systems that should be created by the trace_array. (Note if the
trace_array already exists, this parameter is ignored).
The list of systems is saved and if a module is loaded, its events will
not be added unless the system for those events also match the systems
string.
Link: https://lore.kernel.org/linux-trace-kernel/20231213093701.03fddec0@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Arun Easi <aeasi@marvell.com>
Cc: Daniel Wagner <dwagner@suse.de>
Tested-by: Dmytro Maluka <dmaluka@chromium.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
static void
qla_trace_init(void)
{
- qla_trc_array = trace_array_get_by_name("qla2xxx");
+ qla_trc_array = trace_array_get_by_name("qla2xxx", NULL);
if (!qla_trc_array) {
ql_log(ql_log_fatal, NULL, 0x0001,
"Unable to create qla2xxx trace instance, instance logging will be disabled.\n");
const char *fmt, ...);
int trace_array_init_printk(struct trace_array *tr);
void trace_array_put(struct trace_array *tr);
-struct trace_array *trace_array_get_by_name(const char *name);
+struct trace_array *trace_array_get_by_name(const char *name, const char *systems);
int trace_array_destroy(struct trace_array *tr);
/* For osnoise tracer */
static inline void trace_array_put(struct trace_array *tr)
{
}
-static inline struct trace_array *trace_array_get_by_name(const char *name)
+static inline struct trace_array *trace_array_get_by_name(const char *name, const char *systems)
{
return NULL;
}
return ret;
}
-static struct trace_array *trace_array_create(const char *name)
+static struct trace_array *
+trace_array_create_systems(const char *name, const char *systems)
{
struct trace_array *tr;
int ret;
if (!zalloc_cpumask_var(&tr->pipe_cpumask, GFP_KERNEL))
goto out_free_tr;
+ if (systems) {
+ tr->system_names = kstrdup_const(systems, GFP_KERNEL);
+ if (!tr->system_names)
+ goto out_free_tr;
+ }
+
tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS;
cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
free_trace_buffers(tr);
free_cpumask_var(tr->pipe_cpumask);
free_cpumask_var(tr->tracing_cpumask);
+ kfree_const(tr->system_names);
kfree(tr->name);
kfree(tr);
return ERR_PTR(ret);
}
+static struct trace_array *trace_array_create(const char *name)
+{
+ return trace_array_create_systems(name, NULL);
+}
+
static int instance_mkdir(const char *name)
{
struct trace_array *tr;
/**
* trace_array_get_by_name - Create/Lookup a trace array, given its name.
* @name: The name of the trace array to be looked up/created.
+ * @systems: A list of systems to create event directories for (NULL for all)
*
* Returns pointer to trace array with given name.
* NULL, if it cannot be created.
* trace_array_put() is called, user space can not delete it.
*
*/
-struct trace_array *trace_array_get_by_name(const char *name)
+struct trace_array *trace_array_get_by_name(const char *name, const char *systems)
{
struct trace_array *tr;
goto out_unlock;
}
- tr = trace_array_create(name);
+ tr = trace_array_create_systems(name, systems);
if (IS_ERR(tr))
tr = NULL;
free_cpumask_var(tr->pipe_cpumask);
free_cpumask_var(tr->tracing_cpumask);
+ kfree_const(tr->system_names);
kfree(tr->name);
kfree(tr);
if (IS_ENABLED(CONFIG_TRACER_MAX_TRACE))
do_allocate_snapshot(tok);
- tr = trace_array_get_by_name(tok);
+ tr = trace_array_get_by_name(tok, NULL);
if (!tr) {
pr_warn("Failed to create instance buffer %s\n", curr_str);
continue;
unsigned char trace_flags_index[TRACE_FLAGS_MAX_SIZE];
unsigned int flags;
raw_spinlock_t start_lock;
+ const char *system_names;
struct list_head err_log;
struct dentry *dir;
struct dentry *options;
if (!p || *p == '\0')
continue;
- tr = trace_array_get_by_name(p);
+ tr = trace_array_get_by_name(p, NULL);
if (!tr) {
pr_err("Failed to get trace instance %s\n", p);
continue;
up_write(&trace_event_sem);
}
+static bool event_in_systems(struct trace_event_call *call,
+ const char *systems)
+{
+ const char *system;
+ const char *p;
+
+ if (!systems)
+ return true;
+
+ system = call->class->system;
+ p = strstr(systems, system);
+ if (!p)
+ return false;
+
+ if (p != systems && !isspace(*(p - 1)) && *(p - 1) != ',')
+ return false;
+
+ p += strlen(system);
+ return !*p || isspace(*p) || *p == ',';
+}
+
static struct trace_event_file *
trace_create_new_event(struct trace_event_call *call,
struct trace_array *tr)
struct trace_event_file *file;
unsigned int first;
+ if (!event_in_systems(call, tr->system_names))
+ return NULL;
+
file = kmem_cache_alloc(file_cachep, GFP_TRACE);
if (!file)
- return NULL;
+ return ERR_PTR(-ENOMEM);
pid_list = rcu_dereference_protected(tr->filtered_pids,
lockdep_is_held(&event_mutex));
struct trace_event_file *file;
file = trace_create_new_event(call, tr);
+ /*
+ * trace_create_new_event() returns ERR_PTR(-ENOMEM) if failed
+ * allocation, or NULL if the event is not part of the tr->system_names.
+ * When the event is not part of the tr->system_names, return zero, not
+ * an error.
+ */
if (!file)
- return -ENOMEM;
+ return 0;
+
+ if (IS_ERR(file))
+ return PTR_ERR(file);
if (eventdir_initialized)
return event_create_dir(tr->event_dir, file);
int ret;
file = trace_create_new_event(call, tr);
+ /*
+ * trace_create_new_event() returns ERR_PTR(-ENOMEM) if failed
+ * allocation, or NULL if the event is not part of the tr->system_names.
+ * When the event is not part of the tr->system_names, return zero, not
+ * an error.
+ */
if (!file)
- return -ENOMEM;
+ return 0;
+
+ if (IS_ERR(file))
+ return PTR_ERR(file);
ret = event_define_fields(call);
if (ret)
* NOTE: This function increments the reference counter
* associated with the trace array - "tr".
*/
- tr = trace_array_get_by_name("sample-instance");
+ tr = trace_array_get_by_name("sample-instance", "sched,timer,kprobes");
if (!tr)
return -1;
projects / linux-block.git / commitdiff