Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Song Liu <songliubraving@fb.com>
To:     Pedro Tammela <pctammela@gmail.com>
CC:     Pedro Tammela <pctammela@mojatatu.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>, Martin Lau <kafai@fb.com>,
        Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>, Shuah Khan <shuah@kernel.org>,
        Joe Stringer <joe@cilium.io>,
        Quentin Monnet <quentin@isovalent.com>,
        Yang Li <yang.lee@linux.alibaba.com>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "bpf@vger.kernel.org" <bpf@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-kselftest@vger.kernel.org" <linux-kselftest@vger.kernel.org>
Subject: Re: [PATCH bpf-next] libbpf: Add '_wait()' and '_nowait()' macros for
 'bpf_ring_buffer__poll()'
Thread-Topic: [PATCH bpf-next] libbpf: Add '_wait()' and '_nowait()' macros
 for 'bpf_ring_buffer__poll()'
Thread-Index: AQHXI+03ORNntXupUk6L4u8Dfh+Z4qqbKTIA
Date:   Mon, 29 Mar 2021 16:28:18 +0000
Message-ID: <BCF68ADA-5114-4E61-87DE-D5E5C946BC6F@fb.com>
References: <20210328161055.257504-1-pctammela@mojatatu.com>
 <20210328161055.257504-3-pctammela@mojatatu.com>
In-Reply-To: <20210328161055.257504-3-pctammela@mojatatu.com>
Accept-Language: en-US
Content-Language: en-US
Content-Type: text/plain; charset="us-ascii"
Content-ID: <2C97E86928BA2049A6E95A74BA4ECA8F@namprd15.prod.outlook.com>
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: c796a977-2139-4a57-a461-08d8f2cfa96a
X-MS-Exchange-CrossTenant-originalarrivaltime: 29 Mar 2021 16:28:18.6246
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: eEMzW4hXWG99WAQrlLnbkmR5XjLlraYFXkQoY/h75b49zSChEGm4aVOcSKnWPY46iALNqLvMYXOtoC3+g+tZzQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR15MB4680
X-OriginatorOrg: fb.com
X-Proofpoint-GUID: x7958uYfxtXFtYJg_IYqIzE1DFTdvEBD
X-Proofpoint-ORIG-GUID: x7958uYfxtXFtYJg_IYqIzE1DFTdvEBD
X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.369,18.0.761
 definitions=2021-03-29_10:2021-03-26,2021-03-29 signatures=0
X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501
 malwarescore=0 mlxscore=0 bulkscore=0 clxscore=1015 phishscore=0
 mlxlogscore=999 impostorscore=0 spamscore=0 adultscore=0
 lowpriorityscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx
 scancount=1 engine=8.12.0-2103250000 definitions=main-2103290121
X-FB-Internal: deliver
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


> On Mar 28, 2021, at 9:10 AM, Pedro Tammela <pctammela@gmail.com> wrote:
>=20
> 'bpf_ring_buffer__poll()' abstracts the polling method, so abstract the
> constants that make the implementation don't wait or wait indefinetly
> for data.
>=20
> Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
> ---
> tools/lib/bpf/libbpf.h                                 | 3 +++
> tools/testing/selftests/bpf/benchs/bench_ringbufs.c    | 2 +-
> tools/testing/selftests/bpf/prog_tests/ringbuf.c       | 6 +++---
> tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c | 4 ++--
> 4 files changed, 9 insertions(+), 6 deletions(-)
>=20
> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> index f500621d28e5..3817d84f91c6 100644
> --- a/tools/lib/bpf/libbpf.h
> +++ b/tools/lib/bpf/libbpf.h
> @@ -540,6 +540,9 @@ LIBBPF_API int ring_buffer__poll(struct ring_buffer *=
rb, int timeout_ms);
> LIBBPF_API int ring_buffer__consume(struct ring_buffer *rb);
> LIBBPF_API int ring_buffer__epoll_fd(const struct ring_buffer *rb);
>=20
> +#define ring_buffer__poll_wait(rb) ring_buffer__poll(rb, -1)
> +#define ring_buffer__poll_nowait(rb) ring_buffer__poll(rb, 0)

I think we don't need ring_buffer__poll_wait() as ring_buffer__poll() alrea=
dy=20
means "wait for timeout_ms".=20

Actually, I think ring_buffer__poll() is enough. ring_buffer__poll_nowait()=
=20
is not that useful either.=20

Thanks,
Song