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Subject: Re: [PATCH 1/2] kernel/bpf: change "char *" string form to "char []"
To:     liqiong <liqiong@nfschina.com>, Yonghong Song <yhs@fb.com>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>
Cc:     Alexei Starovoitov <ast@kernel.org>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>, netdev@vger.kernel.org,
        bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
        hukun@nfschina.com, qixu@nfschina.com, yuzhe@nfschina.com,
        renyu@nfschina.com
References: <20220512142814.26705-1-liqiong@nfschina.com>
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 <223f19c0-70a7-3b1f-6166-22d494b62b6e@nfschina.com>
From:   Daniel Borkmann <daniel@iogearbox.net>
Message-ID: <92cc4844-5815-c3b0-63be-2e54dc36e1d9@iogearbox.net>
Date:   Thu, 12 May 2022 22:59:31 +0200
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On 5/12/22 7:08 PM, liqiong wrote:
> 在 2022年05月12日 23:16, Yonghong Song 写道:
>>
>> On 5/12/22 7:28 AM, liqiong wrote:
>>> The string form of "char []" declares a single variable. It is better
>>> than "char *" which creates two variables.
>>
>> Could you explain in details about why it is better in generated codes?
>> It is not clear to me why your patch is better than the original code.
> 
> The  string form of "char *" creates two variables in the final assembly output,
> a static string, and a char pointer to the static string.  Use  "objdump -S -D  *.o",
> can find out the static string  occurring  at "Contents of section .rodata".

There are ~360 instances of this type in the tree from a quick grep, do you
plan to convert all them ?

Thanks,
Daniel