From: "Wangnan (F)" <wangnan0@huawei.com>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>,
Linux Kernel list <linux-kernel@vger.kernel.org>,
<pi3orama@163.com>, He Kuang <hekuang@huawei.com>,
Jiri Olsa <jolsa@kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Namhyung Kim <namhyung@kernel.org>, Zefan Li <lizefan@huawei.com>
Subject: Re: [PATCH v9 1/8] perf evlist: Introduce aux evlist
Date: Thu, 23 Jun 2016 09:29:57 +0800 [thread overview]
Message-ID: <576B3B95.8050105@huawei.com> (raw)
In-Reply-To: <20160622134051.GI4213@kernel.org>
On 2016/6/22 21:40, Arnaldo Carvalho de Melo wrote:
> Em Wed, Jun 22, 2016 at 08:17:02AM -0500, Nilay Vaish escreveu:
>> On 22 June 2016 at 04:08, Wang Nan <wangnan0@huawei.com> wrote:
>>> +struct perf_evlist *perf_evlist__new_aux(struct perf_evlist *parent)
>>> +{
>>> + struct perf_evlist *evlist;
>>> +
>>> + if (perf_evlist__is_aux(parent)) {
>>> + pr_err("Internal error: create aux evlist from another aux evlist\n");
>>> + return NULL;
>>> + }
>>> +
>>> + evlist = zalloc(sizeof(*evlist));
>>> + if (!evlist)
>>> + return NULL;
>>> +
>>> + perf_evlist__init(evlist, parent->cpus, parent->threads);
>>> + evlist->parent = parent->parent;
>> A very minor suggestion. I think evlist->parent should be set to
>> 'parent' and not 'parent->parent'. I agree the two values are equal,
>> but setting to parent->parent just does not seem right.
> I felt like that, thought I was missing something, which is always a bad
> feeling when processing a patch... So, Wang, does that have some value
> we are not seeing?
>
> I thought about the possibility of adding an aux2 to an aux1 evlist and
> that making aux2 have the same parent as aux1, but that is checked on
> that pr_err() test...
The pr_err() test is added yesterday to emphasize we don't accept
grandchildren. Before we have this test, setting parent to parent->parent
is a defensive programming. And I think it is clever :)
Thank you.
next prev parent reply other threads:[~2016-06-23 1:30 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-22 9:08 [PATCH v9 0/8] perf tools: Support overwritable ring buffer Wang Nan
2016-06-22 9:08 ` [PATCH v9 1/8] perf evlist: Introduce aux evlist Wang Nan
2016-06-22 13:17 ` Nilay Vaish
2016-06-22 13:40 ` Arnaldo Carvalho de Melo
2016-06-23 1:29 ` Wangnan (F) [this message]
2016-06-23 2:11 ` [PATCH v9.1] " Wang Nan
2016-06-22 9:08 ` [PATCH v9 2/8] perf tests: Add testcase for auxiliary evlist Wang Nan
2016-06-22 9:08 ` [PATCH v9 3/8] perf record: Extract perf_evlist__mmap_ex() processing to a new function Wang Nan
2016-06-22 9:08 ` [PATCH v9 4/8] perf record: Introduce rec->overwrite_evlist for overwritable events Wang Nan
2016-06-22 9:08 ` [PATCH v9 5/8] perf record: Toggle overwrite ring buffer for reading Wang Nan
2016-06-22 14:33 ` Nilay Vaish
2016-06-23 1:19 ` Wangnan (F)
2016-06-22 9:08 ` [PATCH v9 6/8] perf tools: Enable overwrite settings Wang Nan
2016-06-22 9:08 ` [PATCH v9 7/8] perf tools: Don't warn about out of order event if write_backward is used Wang Nan
2016-06-22 9:08 ` [PATCH v9 8/8] perf tools: Add --tail-synthesize option Wang Nan
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