Re: [PATCH] dcache: Define DNAME_INLINE_LEN as a number directly

[Yonghong Song <yonghong.song@linux.dev>]

On 5/20/25 1:04 AM, Alexei Starovoitov wrote:
> On Tue, May 20, 2025 at 1:23 AM Al Viro <viro@zeniv.linux.org.uk> wrote:
>> On Tue, May 20, 2025 at 02:47:07PM +0800, Tiezhu Yang wrote:
>>> When executing the bcc script, there exists the following error
>>> on LoongArch and x86_64:
>> NOTABUG.  You can't require array sizes to contain no arithmetics,
>> including sizeof().  Well, you can, but don't expect your requests
>> to be satisfied.
>>
>>> How to reproduce:
>>>
>>> git clone https://github.com/iovisor/bcc.git
>>> mkdir bcc/build; cd bcc/build
>>> cmake ..
>>> make
>>> sudo make install
>>> sudo /usr/share/bcc/tools/filetop
>> So fix the script.  Or report it to whoever wrote it, if it's
>> not yours.
> +1
>
>> I'm sorry, but we are NOT going to accomodate random parsers
>> poking inside the kernel-internal headers and failing to
>> actually parse the language they are written in.
>>
>> If you want to exfiltrate a constant, do what e.g. asm-offsets is
>> doing.  Take a look at e.g.  arch/loongarch/kernel/asm-offsets.c
>> and check what ends up in include/generated/asm-offsets.h - the
>> latter is entirely produced out of the former.
>>
>> The trick is to have inline asm that would spew a recognizable
>> line when compiled into assembler, with the value(s) you want
>> substituted into it.  See include/linux/kbuild.h for the macros.
>>
>> Then you pick these lines out of generated your_file.s - no need
>> to use python, sed(1) will do just fine.  See filechk_offsets in
>> scripts/Makefile.lib for that part.
> None of it is necessary.
>
> Tiezhu,
>
> bcc's tools/filetop.py is really old and obsolete.
> It's not worth fixing. I'd delete it.
> Use bcc's libbpf-tools/filetop instead.

Tiezhu, please check whether libbpf-tools/filetop satisfied your need or 
not. Thanks!