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From: Hengqi Chen <hengqi.chen@gmail.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: bpf <bpf@vger.kernel.org>, Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>, Yonghong Song <yhs@fb.com>,
	john fastabend <john.fastabend@gmail.com>
Subject: Re: [PATCH bpf-next 2/2] selftests/bpf: Test BPF map creation using BTF-defined key/value
Date: Sun, 3 Oct 2021 00:17:45 +0800	[thread overview]
Message-ID: <6fdca592-693a-f1d5-e2c9-395cfbdb4e6d@gmail.com> (raw)
In-Reply-To: <CAEf4Bzbni1-M=9S=R_xygOYKOFwuOJjcNtJVqQVdTOLjR6512Q@mail.gmail.com>



On 10/1/21 2:39 AM, Andrii Nakryiko wrote:
> On Thu, Sep 30, 2021 at 9:05 AM Hengqi Chen <hengqi.chen@gmail.com> wrote:
>>
>>
>>
>> On 9/9/21 12:29 PM, Andrii Nakryiko wrote:
>>> On Sun, Sep 5, 2021 at 3:09 AM Hengqi Chen <hengqi.chen@gmail.com> wrote:
>>>>
>>>> Test BPF map creation using BTF-defined key/value. The test defines
>>>> some specialized maps by specifying BTF types for key/value and
>>>> checks those maps are correctly initialized and loaded.
>>>>
>>>> Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
>>>> ---
>>>>  .../selftests/bpf/prog_tests/map_create.c     |  87 ++++++++++++++
>>>>  .../selftests/bpf/progs/test_map_create.c     | 110 ++++++++++++++++++
>>>>  2 files changed, 197 insertions(+)
>>>>  create mode 100644 tools/testing/selftests/bpf/prog_tests/map_create.c
>>>>  create mode 100644 tools/testing/selftests/bpf/progs/test_map_create.c
>>>>
>>>> diff --git a/tools/testing/selftests/bpf/prog_tests/map_create.c b/tools/testing/selftests/bpf/prog_tests/map_create.c
>>>> new file mode 100644
>>>> index 000000000000..6ca32d0dffd2
>>>> --- /dev/null
>>>> +++ b/tools/testing/selftests/bpf/prog_tests/map_create.c
>>>> @@ -0,0 +1,87 @@
>>>> +/* SPDX-License-Identifier: GPL-2.0 */
>>>> +/* Copyright (c) 2021 Hengqi Chen */
>>>> +
>>>> +#include <test_progs.h>
>>>> +#include "test_map_create.skel.h"
>>>> +
>>>> +void test_map_create(void)
>>>> +{
>>>> +       struct test_map_create *skel;
>>>> +       int err, fd;
>>>> +
>>>> +       skel = test_map_create__open();
>>>> +       if (!ASSERT_OK_PTR(skel, "test_map_create__open failed"))
>>>> +               return;
>>>> +
>>>> +       err = test_map_create__load(skel);
>>>
>>> If load() succeeds, all the maps will definitely be created, so all
>>> the below tests are meaningless.
>>>
>>> I think it's better to just change all the existing map definitions
>>> used throughout selftests to use key/value types, instead of
>>> key_size/value_size. That will automatically test this feature without
>>> adding an extra test. Unfortunately to really test that the logic is
>>> working, we'd need to check that libbpf doesn't emit the warning about
>>> retrying map creation w/o BTF, but I think one-time manual check
>>> (please use ./test_progs -v to see libbpf warnings during tests)
>>> should be sufficient for this.
>>>
>>
>> Hello, Andrii
>>
>> I updated these existing tests as you suggested,
>> but I was unable to run the whole bpf selftests locally.
>>
>> Running ./test_progs -v made my system hang up,
>> didn't find the root cause yet.
> 
> This is strange. Do you know at which test this happens? Do you get
> kernel warning/oops when this happens in dmesg?
> 

No, when this situation occurred, I just restarted my laptop.
Will look into this later.

> But overall, the development and testing workflow for people working
> on bpf/bpf-next involves building latest kernel and running selftests
> inside the QEMU VM for testing. We also have vmtest.sh script in
> selftests/bpf that automates a lot of building steps. It will build
> kernel, test_progs and other selftest binaries, and will spin up QEMU
> VM with the same image that our BPF CIs are using. You just need to
> have very recent/latest Clang available and similarly pahole (from
> dwarves package) should be up to date and available through $PATH.
> After that, running ./vmtest.sh will just run all ./test_progs
> automatically.
> 

This workflow info is quite useful for me. Thanks.

> Either way, our CI will also run your changes through the tests
> (except there are some intermittent issues right now, so we'll have to
> wait a bit for that to kick in). You can monitor [0], or the link will
> actually appear on each of your patches (e.g., [1]) in "Checks"
> section, once everything is up and running properly.
> 
>   [0] https://github.com/kernel-patches/bpf/pulls
>   [1] https://patchwork.kernel.org/project/netdevbpf/patch/20210930161456.3444544-2-hengqi.chen@gmail.com/
> 
>>
>> Instead I just run the modified test with the following commands:
>>
>> sudo ./test_progs -v --name=kfree_skb,perf_event_stackmap,btf_map_in_map,pe_preserve_elems,stacktrace_map,stacktrace_build_id,xdp_bpf2bpf,select_reuseport,tcpbpf_user
>>
>>>> +       if (!ASSERT_OK(err, "test_map_create__load failed"))
>>>> +               goto cleanup;
>>>> +
>>>> +       fd = bpf_map__fd(skel->maps.map1);
>>>> +       if (!ASSERT_GT(fd, 0, "bpf_map__fd failed"))
>>>> +               goto cleanup;
>>>> +       close(fd);
>>>> +
>>>> +       fd = bpf_map__fd(skel->maps.map2);
>>>> +       if (!ASSERT_GT(fd, 0, "bpf_map__fd failed"))
>>>> +               goto cleanup;
>>>> +       close(fd);
>>>
>>> [...]
>>>

  reply	other threads:[~2021-10-02 16:17 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-05 10:09 [PATCH bpf-next 1/2] libbpf: Support uniform BTF-defined key/value specification across all BPF maps Hengqi Chen
2021-09-05 10:09 ` [PATCH bpf-next 2/2] selftests/bpf: Test BPF map creation using BTF-defined key/value Hengqi Chen
2021-09-09  4:29   ` Andrii Nakryiko
2021-09-30 16:05     ` Hengqi Chen
2021-09-30 18:39       ` Andrii Nakryiko
2021-10-02 16:17         ` Hengqi Chen [this message]
2021-09-09  4:26 ` [PATCH bpf-next 1/2] libbpf: Support uniform BTF-defined key/value specification across all BPF maps Andrii Nakryiko
2021-09-30 15:58   ` Hengqi Chen

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