From: Yonghong Song <yhs@fb.com>
To: Quentin Monnet <quentin@isovalent.com>, <bpf@vger.kernel.org>,
<netdev@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>, <kernel-team@fb.com>,
Martin KaFai Lau <kafai@fb.com>
Subject: Re: [PATCH bpf-next 09/13] tools/bpftool: add bpftool support for bpf map element iterator
Date: Thu, 16 Jul 2020 10:42:13 -0700 [thread overview]
Message-ID: <c70ebb0a-538c-a84f-f606-1d08af426fde@fb.com> (raw)
In-Reply-To: <9f865c02-291c-8622-b601-f4613356a469@isovalent.com>
On 7/16/20 9:39 AM, Quentin Monnet wrote:
> 2020-07-13 09:17 UTC-0700 ~ Yonghong Song <yhs@fb.com>
>> The optional parameter "map MAP" can be added to "bpftool iter"
>> command to create a bpf iterator for map elements. For example,
>> bpftool iter pin ./prog.o /sys/fs/bpf/p1 map id 333
>>
>> For map element bpf iterator "map MAP" parameter is required.
>> Otherwise, bpf link creation will return an error.
>>
>> Signed-off-by: Yonghong Song <yhs@fb.com>
>> ---
>> .../bpftool/Documentation/bpftool-iter.rst | 16 ++++++++--
>> tools/bpf/bpftool/iter.c | 32 ++++++++++++++++---
>> 2 files changed, 42 insertions(+), 6 deletions(-)
>>
>> diff --git a/tools/bpf/bpftool/Documentation/bpftool-iter.rst b/tools/bpf/bpftool/Documentation/bpftool-iter.rst
>> index 8dce698eab79..53ee4fb188b4 100644
>> --- a/tools/bpf/bpftool/Documentation/bpftool-iter.rst
>> +++ b/tools/bpf/bpftool/Documentation/bpftool-iter.rst
>> @@ -17,14 +17,15 @@ SYNOPSIS
>> ITER COMMANDS
>> ===================
>>
>> -| **bpftool** **iter pin** *OBJ* *PATH*
>> +| **bpftool** **iter pin** *OBJ* *PATH* [**map** *MAP*]
>> | **bpftool** **iter help**
>> |
>> | *OBJ* := /a/file/of/bpf_iter_target.o
>> +| *MAP* := { **id** *MAP_ID* | **pinned** *FILE* }
>
> Please don't change the indentation style (other lines have a tab).
Will fix.
>
>>
>> DESCRIPTION
>> ===========
>> - **bpftool iter pin** *OBJ* *PATH*
>> + **bpftool iter pin** *OBJ* *PATH* [**map** *MAP*]
>> A bpf iterator combines a kernel iterating of
>> particular kernel data (e.g., tasks, bpf_maps, etc.)
>> and a bpf program called for each kernel data object
>> @@ -37,6 +38,10 @@ DESCRIPTION
>> character ('.'), which is reserved for future extensions
>> of *bpffs*.
>>
>> + Map element bpf iterator requires an additional parameter
>> + *MAP* so bpf program can iterate over map elements for
>> + that map.
>> +
>
> Same note on indentation.
>
> Could you please also explain in a few words what the "Map element bpf
> iterator" is? Reusing part of your cover letter (see below) could do,
> it's just so that users not familiar with the concept can get an idea of
> what it does.
Will do.
>
> ---
> User can have a bpf program in kernel to run with each map element,
> do checking, filtering, aggregation, etc. without copying data
> to user space.
> ---
>
>> User can then *cat PATH* to see the bpf iterator output.
>>
>> **bpftool iter help**
>
> [...]
>
>> @@ -62,13 +83,16 @@ static int do_pin(int argc, char **argv)
>> bpf_link__destroy(link);
>> close_obj:
>> bpf_object__close(obj);
>> +close_map_fd:
>> + if (map_fd >= 0)
>> + close(map_fd);
>> return err;
>> }
>>
>> static int do_help(int argc, char **argv)
>> {
>> fprintf(stderr,
>> - "Usage: %1$s %2$s pin OBJ PATH\n"
>> + "Usage: %1$s %2$s pin OBJ PATH [map MAP]\n"
>
> You probably want to add HELP_SPEC_MAP (as in map.c) to tell the user
> what MAP should be.
Good suggestion.
>
> Could you please also update the bash completion?
This is always my hardest part! In this case it is
bpftool iter pin <filedir> <filedir> [map MAP]
Any particular existing bpftool implementation I can imitate?
>
> Thanks,
> Quentin
>
next prev parent reply other threads:[~2020-07-16 17:42 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-13 16:17 [PATCH bpf-next 00/13] bpf: implement bpf iterator for map elements Yonghong Song
2020-07-13 16:17 ` [PATCH bpf-next 01/13] bpf: refactor bpf_iter_reg to have separate seq_info member Yonghong Song
2020-07-13 16:17 ` [PATCH bpf-next 02/13] bpf: refactor to provide aux info to bpf_iter_init_seq_priv_t Yonghong Song
2020-07-13 16:17 ` [PATCH bpf-next 03/13] bpf: support readonly buffer in verifier Yonghong Song
2020-07-13 23:25 ` Alexei Starovoitov
2020-07-15 17:34 ` Yonghong Song
2020-07-15 17:52 ` Alexei Starovoitov
2020-07-13 16:17 ` [PATCH bpf-next 04/13] bpf: implement bpf iterator for map elements Yonghong Song
2020-07-13 16:17 ` [PATCH bpf-next 05/13] bpf: implement bpf iterator for hash maps Yonghong Song
2020-07-13 16:17 ` [PATCH bpf-next 06/13] bpf: implement bpf iterator for array maps Yonghong Song
2020-07-13 18:49 ` kernel test robot
2020-07-13 16:17 ` [PATCH bpf-next 07/13] bpf: implement bpf iterator for sock local storage map Yonghong Song
2020-07-13 16:17 ` [PATCH bpf-next 08/13] tools/libbpf: add support for bpf map element iterator Yonghong Song
2020-07-13 16:17 ` [PATCH bpf-next 09/13] tools/bpftool: add bpftool " Yonghong Song
2020-07-16 16:39 ` Quentin Monnet
2020-07-16 17:42 ` Yonghong Song [this message]
2020-07-17 12:57 ` Quentin Monnet
2020-07-17 18:52 ` Yonghong Song
2020-07-13 16:17 ` [PATCH bpf-next 10/13] selftests/bpf: add test for bpf hash map iterators Yonghong Song
2020-07-13 16:17 ` [PATCH bpf-next 11/13] selftests/bpf: add test for bpf array " Yonghong Song
2020-07-13 16:17 ` [PATCH bpf-next 12/13] selftests/bpf: add a test for bpf sk_storage_map iterator Yonghong Song
2020-07-13 16:17 ` [PATCH bpf-next 13/13] selftests/bpf: add a test for out of bound rdonly buf access Yonghong Song
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