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From: Jiri Olsa <jolsa@redhat.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>, Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	Martin KaFai Lau <kafai@fb.com>, David Miller <davem@redhat.com>,
	John Fastabend <john.fastabend@gmail.com>,
	Wenbo Zhang <ethercflow@gmail.com>,
	KP Singh <kpsingh@chromium.org>, Andrii Nakryiko <andriin@fb.com>,
	Brendan Gregg <bgregg@netflix.com>,
	Florent Revest <revest@chromium.org>,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH 03/11] bpf: Add btf_ids object
Date: Fri, 19 Jun 2020 15:16:31 +0200	[thread overview]
Message-ID: <20200619131631.GE2465907@krava> (raw)
In-Reply-To: <CAEf4BzZivgf2r+tAnY4+cMTKN3dCb_M-PyVWL_ZSa7SY=x2efA@mail.gmail.com>

On Thu, Jun 18, 2020 at 06:06:49PM -0700, Andrii Nakryiko wrote:

SNIP

> > > +/*
> > > + * The BTF_ID_LIST macro defines pure (unsorted) list
> > > + * of BTF IDs, with following layout:
> > > + *
> > > + * BTF_ID_LIST(list1)
> > > + * BTF_ID(type1, name1)
> > > + * BTF_ID(type2, name2)
> > > + *
> > > + * list1:
> > > + * __BTF_ID__type1__name1__1:
> > > + * .zero 4
> > > + * __BTF_ID__type2__name2__2:
> > > + * .zero 4
> > > + *
> > > + */
> > > +#define BTF_ID_LIST(name)                              \
> >
> > nit: btw, you call it a list here, but btfids tool talks about
> > "sorts". Maybe stick to consistent naming. Either "list" or "set"
> > seems to be appropriate. Set implies a sorted aspect a bit more, IMO.

so how about we keep BTF_ID_LIST as it is and rename
BTF_WHITELIST_* to BTF_SET_*

> >
> > > +asm(                                                   \
> > > +".pushsection " SECTION ",\"a\";               \n"     \
> > > +".global " #name ";                            \n"     \
> >
> > I was expecting to see reserved 4 bytes for list size? I also couldn't
> > find where btfids tool prepends it. From what I could understand, it
> > just assumed the first 4 bytes are the length prefix? Sorry if I'm
> > slow...
> 
> Never mind, this is different from whitelisting you do in patch #8.
> But now I'm curious how this list symbol gets its size correctly
> calculated?..

so the BTF_ID_LIST list does not care about the size,
each symbol in the 'list' gets resolved based on its
__BTF_ID__XX__symbol__XX symbol

the count is kept in BTF_WHITELIST_* list because we
need it to sort it and search in it

thanks,
jirka


  reply	other threads:[~2020-06-19 13:16 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-16 10:05 [PATCHv3 0/9] bpf: Add d_path helper Jiri Olsa
2020-06-16 10:05 ` [PATCH 01/11] bpf: Add btfid tool to resolve BTF IDs in ELF object Jiri Olsa
2020-06-19  0:38   ` Andrii Nakryiko
2020-06-19 13:03     ` Jiri Olsa
2020-06-19 18:12       ` Andrii Nakryiko
2020-06-22  8:59         ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 02/11] bpf: Compile btfid tool at kernel compilation start Jiri Olsa
2020-06-18 20:40   ` John Fastabend
2020-06-18 21:17     ` John Fastabend
2020-06-19 13:23     ` Jiri Olsa
2020-06-19  0:40   ` Andrii Nakryiko
2020-06-19  0:47     ` Arnaldo Carvalho de Melo
2020-06-19  2:08       ` Alexei Starovoitov
2020-06-19  3:51         ` Andrii Nakryiko
2020-06-16 10:05 ` [PATCH 03/11] bpf: Add btf_ids object Jiri Olsa
2020-06-19  0:56   ` Andrii Nakryiko
2020-06-19  1:06     ` Andrii Nakryiko
2020-06-19 13:16       ` Jiri Olsa [this message]
2020-06-19 13:13     ` Jiri Olsa
2020-06-19 18:15       ` Andrii Nakryiko
2020-06-19  1:02   ` Andrii Nakryiko
2020-06-19 13:05     ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 04/11] bpf: Resolve BTF IDs in vmlinux image Jiri Olsa
2020-06-16 10:05 ` [PATCH 05/11] bpf: Remove btf_id helpers resolving Jiri Olsa
2020-06-19  1:10   ` Andrii Nakryiko
2020-06-19 13:18     ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 06/11] bpf: Do not pass enum bpf_access_type to btf_struct_access Jiri Olsa
2020-06-19  3:58   ` Andrii Nakryiko
2020-06-19 13:23     ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 07/11] bpf: Allow nested BTF object to be refferenced by BTF object + offset Jiri Olsa
2020-06-16 10:05 ` [PATCH 08/11] bpf: Add BTF whitelist support Jiri Olsa
2020-06-19  4:29   ` Andrii Nakryiko
2020-06-19 13:29     ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 09/11] bpf: Add d_path helper Jiri Olsa
2020-06-19  4:35   ` Andrii Nakryiko
2020-06-19 13:31     ` Jiri Olsa
2020-06-19 18:25       ` Andrii Nakryiko
2020-06-22  9:02         ` Jiri Olsa
2020-06-22 19:18           ` Andrii Nakryiko
2020-06-23 10:02             ` Jiri Olsa
2020-06-23 18:58               ` Andrii Nakryiko
2020-06-23 20:14                 ` Jiri Olsa
2020-06-23 20:17                   ` Andrii Nakryiko
2020-06-16 10:05 ` [PATCH 10/11] selftests/bpf: Add verifier test for " Jiri Olsa
2020-06-19  4:38   ` Andrii Nakryiko
2020-06-19 13:32     ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 11/11] selftests/bpf: Add " Jiri Olsa
2020-06-19  4:44   ` Andrii Nakryiko
2020-06-19 13:34     ` Jiri Olsa
2020-06-18 20:57 ` [PATCHv3 0/9] bpf: Add " John Fastabend
2020-06-19 12:35   ` Jiri Olsa

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