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From:   Song Liu <song@kernel.org>
Date:   Tue, 22 Feb 2022 21:26:39 -0800
Message-ID: <CAPhsuW6UHZYr49gSMo6bo_F9dd14SBDN=GGM4PeTTxJQPUCEPw@mail.gmail.com>
Subject: Re: [PATCH bpf-next v3 2/2] bpf: Make BPF_JIT_DEFAULT_ON selectable
 in Kconfig
To:     Tiezhu Yang <yangtiezhu@loongson.cn>
Cc:     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>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Xuefeng Li <lixuefeng@loongson.cn>,
        Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
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On Tue, Feb 22, 2022 at 1:57 AM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
>
> Currently, only x86, arm64 and s390 select ARCH_WANT_DEFAULT_BPF_JIT,
> the other archs do not select ARCH_WANT_DEFAULT_BPF_JIT. On the archs
> without ARCH_WANT_DEFAULT_BPF_JIT, if we want to set bpf_jit_enable to
> 1 by default, the only way is to enable CONFIG_BPF_JIT_ALWAYS_ON, then
> the users can not change it to 0 or 2, it seems bad for some users. We
> can select ARCH_WANT_DEFAULT_BPF_JIT for those archs if it is proper,
> but at least for now, make BPF_JIT_DEFAULT_ON selectable can give them
> a chance.
>
> Additionally, with this patch, under !BPF_JIT_ALWAYS_ON, we can disable
> BPF_JIT_DEFAULT_ON on the archs with ARCH_WANT_DEFAULT_BPF_JIT when make
> menuconfig, it seems flexible for some developers.
>
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>

Acked-by: Song Liu <songliubraving@fb.com>