From: "zhangwei(Jovi)" <jovi.zhangwei@huawei.com>
To: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: <rostedt@goodmis.org>, <masami.hiramatsu.pt@hitachi.com>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 03/11] tracing: add soft disable for syscall events
Date: Sat, 29 Jun 2013 14:26:40 +0800 [thread overview]
Message-ID: <51CE7E20.9030909@huawei.com> (raw)
In-Reply-To: <d7a32766817e9050997629b195676e357e410726.1372479499.git.tom.zanussi@linux.intel.com>
On 2013/6/29 13:08, Tom Zanussi wrote:
> Add support for SOFT_DISABLE to syscall events.
>
> The original SOFT_DISABLE patches didn't add support for soft disable
> of syscall events; this adds it and paves the way for future patches
> allowing triggers to be added to syscall events, since triggers are
> built on top of SOFT_DISABLE.
>
> The existing code grabs the trace_array from the ftrace_file passed to
> the event registration functions and passes that to the probe
> functions. Passing the file instead allows the probe functions to
> access not only the trace_array attached to the file but the flags as
> well.
>
> Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
> ---
> kernel/trace/trace_syscalls.c | 20 ++++++++++++++------
> 1 file changed, 14 insertions(+), 6 deletions(-)
>
> diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
> index 8f2ac73..1765088 100644
> --- a/kernel/trace/trace_syscalls.c
> +++ b/kernel/trace/trace_syscalls.c
> @@ -301,7 +301,8 @@ static int __init syscall_exit_define_fields(struct ftrace_event_call *call)
>
> static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
> {
> - struct trace_array *tr = data;
> + struct ftrace_event_file *ftrace_file = data;
> + struct trace_array *tr = ftrace_file->tr;
> struct syscall_trace_enter *entry;
> struct syscall_metadata *sys_data;
> struct ring_buffer_event *event;
> @@ -319,6 +320,9 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
> if (!sys_data)
> return;
>
> + if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
> + return;
> +
> size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
>
> buffer = tr->trace_buffer.buffer;
> @@ -338,7 +342,8 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
>
> static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
> {
> - struct trace_array *tr = data;
> + struct ftrace_event_file *ftrace_file = data;
> + struct trace_array *tr = ftrace_file->tr;
> struct syscall_trace_exit *entry;
> struct syscall_metadata *sys_data;
> struct ring_buffer_event *event;
> @@ -355,6 +360,9 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
> if (!sys_data)
> return;
>
> + if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
> + return;
> +
> buffer = tr->trace_buffer.buffer;
> event = trace_buffer_lock_reserve(buffer,
> sys_data->exit_event->event.type, sizeof(*entry), 0, 0);
> @@ -382,7 +390,7 @@ static int reg_event_syscall_enter(struct ftrace_event_file *file,
> return -ENOSYS;
> mutex_lock(&syscall_trace_lock);
> if (!tr->sys_refcount_enter)
> - ret = register_trace_sys_enter(ftrace_syscall_enter, tr);
> + ret = register_trace_sys_enter(ftrace_syscall_enter, file);
> if (!ret) {
> set_bit(num, tr->enabled_enter_syscalls);
> tr->sys_refcount_enter++;
Is this change can work correctly?
It seems that all syscalls in same tr will use same ftrace_event_file(first registered)
in ftrace_syscall_enter/ftrace_syscall_exit, obviously this is wrong.
Basically I think we still need pass tr into register_trace_sys_enter/exit, for
performance reason. If you use ftrace_event_file as argument, then when your are
using command 'perf stat -e syscalls:* -a sleep 10',
it will looping NR_SYSCALLS tracepoints for every syscall enter and exit,
that's unacceptable.
Thanks.
> @@ -404,7 +412,7 @@ static void unreg_event_syscall_enter(struct ftrace_event_file *file,
> tr->sys_refcount_enter--;
> clear_bit(num, tr->enabled_enter_syscalls);
> if (!tr->sys_refcount_enter)
> - unregister_trace_sys_enter(ftrace_syscall_enter, tr);
> + unregister_trace_sys_enter(ftrace_syscall_enter, file);
> mutex_unlock(&syscall_trace_lock);
> }
>
> @@ -420,7 +428,7 @@ static int reg_event_syscall_exit(struct ftrace_event_file *file,
> return -ENOSYS;
> mutex_lock(&syscall_trace_lock);
> if (!tr->sys_refcount_exit)
> - ret = register_trace_sys_exit(ftrace_syscall_exit, tr);
> + ret = register_trace_sys_exit(ftrace_syscall_exit, file);
> if (!ret) {
> set_bit(num, tr->enabled_exit_syscalls);
> tr->sys_refcount_exit++;
> @@ -442,7 +450,7 @@ static void unreg_event_syscall_exit(struct ftrace_event_file *file,
> tr->sys_refcount_exit--;
> clear_bit(num, tr->enabled_exit_syscalls);
> if (!tr->sys_refcount_exit)
> - unregister_trace_sys_exit(ftrace_syscall_exit, tr);
> + unregister_trace_sys_exit(ftrace_syscall_exit, file);
> mutex_unlock(&syscall_trace_lock);
> }
>
>
next prev parent reply other threads:[~2013-06-29 6:27 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-29 5:08 [PATCH v2 00/11] tracing: trace event triggers Tom Zanussi
2013-06-29 5:08 ` [PATCH v2 01/11] tracing: simplify event_enable_read() Tom Zanussi
2013-06-29 5:08 ` [PATCH v2 02/11] tracing: add missing syscall_metadata comment Tom Zanussi
2013-06-29 5:08 ` [PATCH v2 03/11] tracing: add soft disable for syscall events Tom Zanussi
2013-06-29 6:26 ` zhangwei(Jovi) [this message]
2013-07-01 11:26 ` Masami Hiramatsu
2013-06-29 5:08 ` [PATCH v2 04/11] tracing: fix disabling of soft disable Tom Zanussi
2013-06-29 5:08 ` [PATCH v2 05/11] tracing: add basic event trigger framework Tom Zanussi
2013-06-29 5:08 ` [PATCH v2 06/11] tracing: add 'traceon' and 'traceoff' event trigger commands Tom Zanussi
2013-06-29 5:08 ` [PATCH v2 07/11] tracing: add 'snapshot' event trigger command Tom Zanussi
2013-06-29 5:08 ` [PATCH v2 08/11] tracing: add 'stacktrace' " Tom Zanussi
2013-06-29 5:08 ` [PATCH v2 09/11] tracing: add 'enable_event' and 'disable_event' event trigger commands Tom Zanussi
2013-06-29 5:08 ` [PATCH v2 10/11] tracing: add and use generic set_trigger_filter() implementation Tom Zanussi
2013-06-29 5:08 ` [PATCH v2 11/11] tracing: add documentation for trace event triggers Tom Zanussi
2013-06-29 9:30 ` [PATCH v2 00/11] tracing: " zhangwei(Jovi)
2013-07-01 12:32 ` Masami Hiramatsu
2013-07-02 4:53 ` zhangwei(Jovi)
2013-07-01 15:49 ` Tom Zanussi
2013-07-02 3:54 ` zhangwei(Jovi)
2013-07-02 14:46 ` Tom Zanussi
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