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From:   Cong Wang <xiyou.wangcong@gmail.com>
Date:   Thu, 15 Apr 2021 08:51:22 -0700
Message-ID: <CAM_iQpVc=0YtKLdEZNPDjA5H84UH50pZ4uFjQ1h=qO-+eUJn-Q@mail.gmail.com>
Subject: Re: [RFC Patch bpf-next] bpf: introduce bpf timer
To:     Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc:     Linux Kernel Network Developers <netdev@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>, duanxiongchun@bytedance.com,
        Dongdong Wang <wangdongdong.6@bytedance.com>,
        Muchun Song <songmuchun@bytedance.com>,
        Cong Wang <cong.wang@bytedance.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>
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On Wed, Apr 14, 2021 at 9:25 PM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> As I said earlier:
> "
> If prog refers such hmap as above during prog free the kernel does
> for_each_map_elem {if (elem->opaque) del_timer().}
> "

This goes back to our previous discussion. Forcing timer deletions on
prog exit is not what we want. The whole point of using a map is to
extend the lifetime of a timer, that is, as long as the map exists, the
timers within it could be still running too.

Thanks.