From dc300d77b86a122d3fd099206e1adf699ed80bd7 Mon Sep 17 00:00:00 2001 From: Wei Yang Date: Sun, 12 Jul 2020 09:10:35 +0800 Subject: tracing: toplevel d_entry already initialized Currently we have following call flow: tracer_init_tracefs() tracing_init_dentry() event_trace_init() tracing_init_dentry() This shows tracing_init_dentry() is called twice in this flow and this is not necessary. Let's remove the second one when it is for sure be properly initialized. Link: https://lkml.kernel.org/r/20200712011036.70948-4-richard.weiyang@linux.alibaba.com Signed-off-by: Wei Yang Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_events.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) (limited to 'kernel/trace/trace_events.c') diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index a85effb2373b..ee25d849ebba 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -3434,7 +3434,6 @@ early_initcall(event_trace_enable_again); __init int event_trace_init(void) { struct trace_array *tr; - struct dentry *d_tracer; struct dentry *entry; int ret; @@ -3442,11 +3441,7 @@ __init int event_trace_init(void) if (!tr) return -ENODEV; - d_tracer = tracing_init_dentry(); - if (IS_ERR(d_tracer)) - return 0; - - entry = tracefs_create_file("available_events", 0444, d_tracer, + entry = tracefs_create_file("available_events", 0444, NULL, tr, &ftrace_avail_fops); if (!entry) pr_warn("Could not create tracefs 'available_events' entry\n"); @@ -3457,7 +3452,7 @@ __init int event_trace_init(void) if (trace_define_common_fields()) pr_warn("tracing: Failed to allocate common fields"); - ret = early_event_add_tracer(d_tracer, tr); + ret = early_event_add_tracer(NULL, tr); if (ret) return ret; -- cgit v1.2.3 From ac343da7bc9048629f9d12d98e8f0573df88836b Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 10 Sep 2020 21:38:48 +0900 Subject: tracing: Define event fields early stage Define event fields at early stage so that boot-time tracing can access the event fields (like per-event filter setting). Link: https://lkml.kernel.org/r/159974152862.478751.2023768466808361350.stgit@devnote2 Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_events.c | 92 +++++++++++++++++++++++++++------------------ 1 file changed, 55 insertions(+), 37 deletions(-) (limited to 'kernel/trace/trace_events.c') diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index ee25d849ebba..8e87fbab6930 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -2123,12 +2123,48 @@ event_subsystem_dir(struct trace_array *tr, const char *name, return NULL; } +static int +event_define_fields(struct trace_event_call *call) +{ + struct list_head *head; + int ret = 0; + + /* + * Other events may have the same class. Only update + * the fields if they are not already defined. + */ + head = trace_get_fields(call); + if (list_empty(head)) { + struct trace_event_fields *field = call->class->fields_array; + unsigned int offset = sizeof(struct trace_entry); + + for (; field->type; field++) { + if (field->type == TRACE_FUNCTION_TYPE) { + field->define_fields(call); + break; + } + + offset = ALIGN(offset, field->align); + ret = trace_define_field(call, field->type, field->name, + offset, field->size, + field->is_signed, field->filter_type); + if (WARN_ON_ONCE(ret)) { + pr_err("error code is %d\n", ret); + break; + } + + offset += field->size; + } + } + + return ret; +} + static int event_create_dir(struct dentry *parent, struct trace_event_file *file) { struct trace_event_call *call = file->event_call; struct trace_array *tr = file->tr; - struct list_head *head; struct dentry *d_events; const char *name; int ret; @@ -2162,35 +2198,10 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file) &ftrace_event_id_fops); #endif - /* - * Other events may have the same class. Only update - * the fields if they are not already defined. - */ - head = trace_get_fields(call); - if (list_empty(head)) { - struct trace_event_fields *field = call->class->fields_array; - unsigned int offset = sizeof(struct trace_entry); - - for (; field->type; field++) { - if (field->type == TRACE_FUNCTION_TYPE) { - ret = field->define_fields(call); - break; - } - - offset = ALIGN(offset, field->align); - ret = trace_define_field(call, field->type, field->name, - offset, field->size, - field->is_signed, field->filter_type); - if (ret) - break; - - offset += field->size; - } - if (ret < 0) { - pr_warn("Could not initialize trace point events/%s\n", - name); - return -1; - } + ret = event_define_fields(call); + if (ret < 0) { + pr_warn("Could not initialize trace point events/%s\n", name); + return ret; } /* @@ -2493,7 +2504,7 @@ __trace_early_add_new_event(struct trace_event_call *call, if (!file) return -ENOMEM; - return 0; + return event_define_fields(call); } struct ftrace_module_file_ops; @@ -3431,6 +3442,18 @@ static __init int event_trace_enable_again(void) early_initcall(event_trace_enable_again); +/* Init fields which doesn't related to the tracefs */ +static __init int event_trace_init_fields(void) +{ + if (trace_define_generic_fields()) + pr_warn("tracing: Failed to allocated generic fields"); + + if (trace_define_common_fields()) + pr_warn("tracing: Failed to allocate common fields"); + + return 0; +} + __init int event_trace_init(void) { struct trace_array *tr; @@ -3446,12 +3469,6 @@ __init int event_trace_init(void) if (!entry) pr_warn("Could not create tracefs 'available_events' entry\n"); - if (trace_define_generic_fields()) - pr_warn("tracing: Failed to allocated generic fields"); - - if (trace_define_common_fields()) - pr_warn("tracing: Failed to allocate common fields"); - ret = early_event_add_tracer(NULL, tr); if (ret) return ret; @@ -3469,6 +3486,7 @@ void __init trace_event_init(void) event_trace_memsetup(); init_ftrace_syscalls(); event_trace_enable(); + event_trace_init_fields(); } #ifdef CONFIG_EVENT_TRACE_STARTUP_TEST -- cgit v1.2.3 From a838deab4e635994476bfc5b254bdf461e168752 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 10 Sep 2020 21:38:58 +0900 Subject: tracing: Enable adding dynamic events early stage Split the event fields initialization from creating new event directory. This allows the boot-time tracing to define dynamic events before initializing events directory on tracefs. Link: https://lkml.kernel.org/r/159974153790.478751.3475515065034825374.stgit@devnote2 Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_events.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'kernel/trace/trace_events.c') diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 8e87fbab6930..42c0e7df6e70 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -38,6 +38,7 @@ DEFINE_MUTEX(event_mutex); LIST_HEAD(ftrace_events); static LIST_HEAD(ftrace_generic_fields); static LIST_HEAD(ftrace_common_fields); +static bool eventdir_initialized; #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO) @@ -2486,7 +2487,10 @@ __trace_add_new_event(struct trace_event_call *call, struct trace_array *tr) if (!file) return -ENOMEM; - return event_create_dir(tr->event_dir, file); + if (eventdir_initialized) + return event_create_dir(tr->event_dir, file); + else + return event_define_fields(call); } /* @@ -3478,6 +3482,9 @@ __init int event_trace_init(void) if (ret) pr_warn("Failed to register trace events module notifier\n"); #endif + + eventdir_initialized = true; + return 0; } -- cgit v1.2.3 From 720dee53ad8dfd528941fbbc264574601b04488a Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Fri, 25 Sep 2020 01:40:08 +0900 Subject: tracing/boot: Initialize per-instance event list in early boot Initialize per-instance event list in early boot time (before initializing instance directory on tracefs). This fixes boot-time tracing to correctly handle the boot-time per-instance settings. Link: https://lkml.kernel.org/r/160096560826.182763.17110991546046128881.stgit@devnote2 Fixes: 4114fbfd02f1 ("tracing: Enable creating new instance early boot") Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 3 ++- kernel/trace/trace.h | 1 + kernel/trace/trace_events.c | 30 ++++++++++++++++-------------- 3 files changed, 19 insertions(+), 15 deletions(-) (limited to 'kernel/trace/trace_events.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 6211a13b3327..3f2533adae72 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8700,7 +8700,8 @@ static struct trace_array *trace_array_create(const char *name) ret = trace_array_create_dir(tr); if (ret) goto out_free_tr; - } + } else + __trace_early_add_events(tr); list_add(&tr->list, &ftrace_trace_arrays); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 525434145eea..5b0e797cacdd 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1658,6 +1658,7 @@ extern void trace_event_enable_tgid_record(bool enable); extern int event_trace_init(void); extern int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr); extern int event_trace_del_tracer(struct trace_array *tr); +extern void __trace_early_add_events(struct trace_array *tr); extern struct trace_event_file *__find_event_file(struct trace_array *tr, const char *system, diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 42c0e7df6e70..851ab37058dd 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -3131,14 +3131,13 @@ static inline int register_event_cmds(void) { return 0; } #endif /* CONFIG_DYNAMIC_FTRACE */ /* - * The top level array has already had its trace_event_file - * descriptors created in order to allow for early events to - * be recorded. This function is called after the tracefs has been - * initialized, and we now have to create the files associated - * to the events. + * The top level array and trace arrays created by boot-time tracing + * have already had its trace_event_file descriptors created in order + * to allow for early events to be recorded. + * This function is called after the tracefs has been initialized, + * and we now have to create the files associated to the events. */ -static __init void -__trace_early_add_event_dirs(struct trace_array *tr) +static void __trace_early_add_event_dirs(struct trace_array *tr) { struct trace_event_file *file; int ret; @@ -3153,13 +3152,12 @@ __trace_early_add_event_dirs(struct trace_array *tr) } /* - * For early boot up, the top trace array requires to have - * a list of events that can be enabled. This must be done before - * the filesystem is set up in order to allow events to be traced - * early. + * For early boot up, the top trace array and the trace arrays created + * by boot-time tracing require to have a list of events that can be + * enabled. This must be done before the filesystem is set up in order + * to allow events to be traced early. */ -static __init void -__trace_early_add_events(struct trace_array *tr) +void __trace_early_add_events(struct trace_array *tr) { struct trace_event_call *call; int ret; @@ -3290,7 +3288,11 @@ int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr) goto out; down_write(&trace_event_sem); - __trace_add_event_dirs(tr); + /* If tr already has the event list, it is initialized in early boot. */ + if (unlikely(!list_empty(&tr->events))) + __trace_early_add_event_dirs(tr); + else + __trace_add_event_dirs(tr); up_write(&trace_event_sem); out: -- cgit v1.2.3