From 2e33af029556cb8bd22bf4f86f42d540249177ea Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 22 Apr 2010 10:35:55 -0400 Subject: tracing: Move fields from event to class structure Move the defined fields from the event to the class structure. Since the fields of the event are defined by the class they belong to, it makes sense to have the class hold the information instead of the individual events. The events of the same class would just hold duplicate information. After this change the size of the kernel dropped another 3K: text data bss dec hex filename 4913961 1088356 861512 6863829 68bbd5 vmlinux.orig 4900252 1057412 861512 6819176 680d68 vmlinux.regs 4900375 1053380 861512 6815267 67fe23 vmlinux.fields Although the text increased, this was mainly due to the C files having to adapt to the change. This is a constant increase, where new tracepoints will not increase the Text. But the big drop is in the data size (as well as needed allocations to hold the fields). This will give even more savings as more tracepoints are created. Note, if just TRACE_EVENT()s are used and not DECLARE_EVENT_CLASS() with several DEFINE_EVENT()s, then the savings will be lost. But we are pushing developers to consolidate events with DEFINE_EVENT() so this should not be an issue. The kprobes define a unique class to every new event, but are dynamic so it should not be a issue. The syscalls however have a single class but the fields for the individual events are different. The syscalls use a metadata to define the fields. I moved the fields list from the event to the metadata and added a "get_fields()" function to the class. This function is used to find the fields. For normal events and kprobes, get_fields() just returns a pointer to the fields list_head in the class. For syscall events, it returns the fields list_head in the metadata for the event. v2: Fixed the syscall fields. The syscall metadata needs a list of fields for both enter and exit. Acked-by: Frederic Weisbecker Acked-by: Mathieu Desnoyers Acked-by: Masami Hiramatsu Cc: Tom Zanussi Cc: Peter Zijlstra Signed-off-by: Steven Rostedt --- kernel/trace/trace_syscalls.c | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) (limited to 'kernel/trace/trace_syscalls.c') diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index a21d366cae4..cceccf0d2e9 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -20,14 +20,37 @@ static int syscall_enter_register(struct ftrace_event_call *event, static int syscall_exit_register(struct ftrace_event_call *event, enum trace_reg type); +static int syscall_enter_define_fields(struct ftrace_event_call *call); +static int syscall_exit_define_fields(struct ftrace_event_call *call); + +static struct list_head * +syscall_get_enter_fields(struct ftrace_event_call *call) +{ + struct syscall_metadata *entry = call->data; + + return &entry->enter_fields; +} + +static struct list_head * +syscall_get_exit_fields(struct ftrace_event_call *call) +{ + struct syscall_metadata *entry = call->data; + + return &entry->exit_fields; +} + struct ftrace_event_class event_class_syscall_enter = { .system = "syscalls", - .reg = syscall_enter_register + .reg = syscall_enter_register, + .define_fields = syscall_enter_define_fields, + .get_fields = syscall_get_enter_fields, }; struct ftrace_event_class event_class_syscall_exit = { .system = "syscalls", - .reg = syscall_exit_register + .reg = syscall_exit_register, + .define_fields = syscall_exit_define_fields, + .get_fields = syscall_get_exit_fields, }; extern unsigned long __start_syscalls_metadata[]; @@ -220,7 +243,7 @@ static void free_syscall_print_fmt(struct ftrace_event_call *call) kfree(call->print_fmt); } -int syscall_enter_define_fields(struct ftrace_event_call *call) +static int syscall_enter_define_fields(struct ftrace_event_call *call) { struct syscall_trace_enter trace; struct syscall_metadata *meta = call->data; @@ -243,7 +266,7 @@ int syscall_enter_define_fields(struct ftrace_event_call *call) return ret; } -int syscall_exit_define_fields(struct ftrace_event_call *call) +static int syscall_exit_define_fields(struct ftrace_event_call *call) { struct syscall_trace_exit trace; int ret; -- cgit v1.2.3