From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: David Ahern <dsahern@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@kernel.org>,
Adrian Hunter <adrian.hunter@intel.com>,
Brendan Gregg <brendan.d.gregg@gmail.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Alexei Starovoitov <ast@kernel.org>,
He Kuang <hekuang@huawei.com>, Jiri Olsa <jolsa@redhat.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Milian Wolff <milian.wolff@kdab.com>,
Namhyung Kim <namhyung@kernel.org>,
Stephane Eranian <eranian@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Vince Weaver <vincent.weaver@maine.edu>,
Wang Nan <wangnan0@huawei.com>, Zefan Li <lizefan@huawei.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH/RFC v2] perf core: Allow setting up max frame stack depth via sysctl
Date: Mon, 25 Apr 2016 17:07:26 -0700 [thread overview]
Message-ID: <20160426000724.GA28705@ast-mbp.thefacebook.com> (raw)
In-Reply-To: <20160425234138.GA16708@kernel.org>
On Mon, Apr 25, 2016 at 08:41:39PM -0300, Arnaldo Carvalho de Melo wrote:
>
> +int sysctl_perf_event_max_stack __read_mostly = PERF_MAX_STACK_DEPTH;
> +
> +static inline size_t perf_callchain_entry__sizeof(void)
> +{
> + return (sizeof(struct perf_callchain_entry) +
> + sizeof(__u64) * sysctl_perf_event_max_stack);
> +}
> @@ -1144,6 +1144,14 @@ static struct ctl_table kern_table[] = {
> .extra1 = &zero,
> .extra2 = &one_hundred,
> },
> + {
> + .procname = "perf_event_max_stack",
> + .data = NULL, /* filled in by handler */
> + .maxlen = sizeof(sysctl_perf_event_max_stack),
> + .mode = 0644,
> + .proc_handler = perf_event_max_stack_handler,
> + .extra1 = &zero,
> + },
you need to define a max value otherwise perf_callchain_entry__sizeof
will overflow. Sure it's root only facility, but still not nice.
1M? Anything above 1M stack frames would be insane anyway.
The rest looks good. Thanks!
next prev parent reply other threads:[~2016-04-26 0:07 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-20 22:47 [PATCH/RFC] " Arnaldo Carvalho de Melo
2016-04-20 23:04 ` Alexei Starovoitov
2016-04-22 20:52 ` [PATCH/RFC v2] " Arnaldo Carvalho de Melo
2016-04-22 21:37 ` Alexei Starovoitov
2016-04-22 22:05 ` David Ahern
2016-04-22 22:18 ` Alexei Starovoitov
2016-04-25 16:14 ` Arnaldo Carvalho de Melo
2016-04-25 16:27 ` Arnaldo Carvalho de Melo
2016-04-25 19:22 ` Arnaldo Carvalho de Melo
2016-04-25 20:06 ` Alexei Starovoitov
2016-04-25 20:17 ` Arnaldo Carvalho de Melo
2016-04-25 21:59 ` Alexei Starovoitov
2016-04-25 23:41 ` Arnaldo Carvalho de Melo
2016-04-26 0:07 ` Alexei Starovoitov [this message]
2016-04-26 0:29 ` [PATCH/RFC v3] " Arnaldo Carvalho de Melo
2016-04-26 0:44 ` Alexei Starovoitov
2016-04-26 0:47 ` Arnaldo Carvalho de Melo
2016-04-26 0:49 ` Brendan Gregg
2016-04-26 16:33 ` Arnaldo Carvalho de Melo
2016-04-26 16:45 ` David Ahern
2016-04-27 13:20 ` Arnaldo Carvalho de Melo
2016-04-26 20:02 ` Brendan Gregg
2016-04-26 21:05 ` Arnaldo Carvalho de Melo
2016-04-26 21:55 ` Peter Zijlstra
2016-04-27 12:53 ` Arnaldo Carvalho de Melo
2016-04-26 21:58 ` Brendan Gregg
2016-04-26 22:10 ` Peter Zijlstra
2016-04-27 12:56 ` Arnaldo Carvalho de Melo
2016-04-26 21:58 ` Frederic Weisbecker
2016-04-27 12:53 ` Arnaldo Carvalho de Melo
2016-04-27 16:09 ` Frederic Weisbecker
2016-04-27 16:27 ` David Ahern
2016-04-27 15:39 ` [tip:perf/core] " tip-bot for Arnaldo Carvalho de Melo
2016-04-20 23:10 ` [PATCH/RFC] " David Ahern
2016-04-21 0:18 ` Arnaldo Carvalho de Melo
2016-04-21 10:48 ` Peter Zijlstra
2016-04-21 15:17 ` Arnaldo Carvalho de Melo
2016-04-21 15:42 ` Arnaldo Carvalho de Melo
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