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From: Taeung Song <treeze.taeung@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
	linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Lai Jiangshan <jiangshanlai@gmail.com>
Subject: Re: [PATCH RESEND 1/3] tracing/syscalls: Rename variable 'nr' to 'syscall_nr'
Date: Fri, 26 Feb 2016 02:26:58 +0900	[thread overview]
Message-ID: <56CF3962.9060400@gmail.com> (raw)
In-Reply-To: <20160225120907.0a30d792@gandalf.local.home>



On 02/26/2016 02:09 AM, Steven Rostedt wrote:
> On Thu, 25 Feb 2016 12:05:01 -0500
> Steven Rostedt <rostedt@goodmis.org> wrote:
>
>> On Fri, 26 Feb 2016 01:53:47 +0900
>> Taeung Song <treeze.taeung@gmail.com> wrote:
>>
>>>
>>> The underlying cause of this problem is not because of
>>> the python script. This problem have relevance to tracing/syscalls
>>> as below.
>>>
>>> # cat
>>> /sys/kernel/debug/tracing/events/syscalls/sys_enter_io_getevents/format
>>> name: sys_enter_io_getevents
>>> ID: 739
>>> format:
>>>          field:unsigned short common_type; offset:0;size:2;signed:0;
>>>          field:unsigned char common_flags; offset:2;size:1;signed:0;
>>>          field:unsigned char common_preempt_count; offset:3;size:1;signed:0;
>>>          field:int common_pid;             offset:4;size:4;signed:1;
>>>          field:int nr;                     offset:8;size:4;signed:1;
>>>          field:aio_context_t ctx_id;       offset:16;size:8;signed:0;
>>>          field:long min_nr;                offset:24;size:8;signed:0;
>>>          field:long nr;                    offset:32;size:8;signed:0;
>>>          field:struct io_event * events;   offset:40;size:8;signed:0;
>>>          field:struct timespec * timeout;  offset:48;size:8;signed:0;
>>>
>>> print fmt: "ctx_id: 0x%08lx, min_nr: 0x%08lx, nr: 0x%08lx, events:
>>> 0x%08lx, timeout: 0x%08lx", ((unsigned long)(REC->ctx_id)), ((unsigned
>>> long)(REC->min_nr)), ((unsigned long)(REC->nr)), ((unsigned
>>> long)(REC->events)), ((unsigned long)(REC->timeout))
>>>
>>>
>>> As you see, there are duplicated variable name among fields.
>>> So I renamed the variable name 'nr' to 'syscall_nr' to avoid this
>>> duplication. As you know 'nr' in print_syscall_enter() mean
>>> system call number so, I changed 'nr' to 'syscall_nr'(IMHO).
>>>
>>
>> The above should have been in the change log. That makes much more
>> sense.
>>

Sorry, this change log is misinterpretable.
So I'm rewriting change log for this patch.
I will resend it soon.

>
> I'm a bit nervous about this change though. Because it is an ABI
> change. Hopefully there's no tools that parse the syscall tracepoints
> and expect to find a 'nr' in there.
>

AFIAIK, I think so but resend this modified patch.

Thanks,
Taeung

      reply	other threads:[~2016-02-25 17:27 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-25 15:24 [PATCH RESEND 1/3] tracing/syscalls: Rename variable 'nr' to 'syscall_nr' Taeung Song
2016-02-25 15:47 ` Steven Rostedt
2016-02-25 16:53   ` Taeung Song
2016-02-25 17:05     ` Steven Rostedt
2016-02-25 17:09       ` Steven Rostedt
2016-02-25 17:26         ` Taeung Song [this message]

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