Message-ID: <555A3C9B.2070309@plumgrid.com>
Date: Mon, 18 May 2015 12:25:15 -0700
From: Alexei Starovoitov <ast@plumgrid.com>
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To: Wang Nan <wangnan0@huawei.com>, paulus@samba.org, a.p.zijlstra@chello.nl,
        mingo@redhat.com, acme@kernel.org, namhyung@kernel.org,
        jolsa@kernel.org, dsahern@gmail.com, daniel@iogearbox.net,
        brendan.d.gregg@gmail.com, masami.hiramatsu.pt@hitachi.com
CC: lizefan@huawei.com, linux-kernel@vger.kernel.org, pi3orama@163.com
Subject: Re: [RFC PATCH v3 33/37] perf bpf: Probe at kprobe points
References: <1431860222-61636-1-git-send-email-wangnan0@huawei.com> <1431860222-61636-34-git-send-email-wangnan0@huawei.com>
In-Reply-To: <1431860222-61636-34-git-send-email-wangnan0@huawei.com>
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On 5/17/15 3:56 AM, Wang Nan wrote:
> In this patch, kprobe points are created using add_perf_probe_events.
> Since all events are already grouped together in an array, calling
> add_perf_probe_events() once creates all of them.
>
> To ensure recover the system when existing, a bpf_unprobe() is also
> provided and hooked to atexit(). Because all of events are in group
> "perf_bpf_probe" (PERF_BPF_PROBE_GROUP), use 'perf_bpf_probe:*' string
> to remove all of them should be a simple method. However, this also
> introduces a constrain that only one instance of 'perf bpf' is allowed
> to be active.

perf bits look ok to me, but I'm not a perf codebase expert.
The above restriction also looks fine for now.
We can relax it later if it really becomes a problem.

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