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Tue, 29 Sep 2020 21:08:39 +0000 From: Song Liu To: Alexei Starovoitov CC: Daniel Borkmann , Network Development , bpf , Kernel Team , Alexei Starovoitov , John Fastabend , KP Singh Subject: Re: [PATCH bpf-next 1/2] bpf: introduce BPF_F_SHARE_PE for perf event array Thread-Topic: [PATCH bpf-next 1/2] bpf: introduce BPF_F_SHARE_PE for perf event array Thread-Index: AQHWlj1FNhN/q3rWS0i/6Efm6LO1bql/pcQAgABTdwCAAATXgIAAAu+AgAAb6gA= Date: Tue, 29 Sep 2020 21:08:39 +0000 Message-ID: <81BFF6AD-A8B7-4D15-AB31-2DEEE904B881@fb.com> References: <20200929084750.419168-1-songliubraving@fb.com> <20200929084750.419168-2-songliubraving@fb.com> <04ba2027-a5ad-d715-ffc8-67f13e40f2d2@iogearbox.net> <20200929190054.4a2chcuxuvicndtu@ast-mbp.dhcp.thefacebook.com> <7c13d40b-fe79-ddbf-2a37-abae1b44de71@iogearbox.net> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-mailer: Apple Mail (2.3608.120.23.2.1) authentication-results: gmail.com; dkim=none (message not signed) header.d=none;gmail.com; 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x-ms-exchange-antispam-messagedata: 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 Content-Type: text/plain; charset="us-ascii" Content-ID: <0CE5F9350559C2448EE51122147696F2@namprd15.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: BYAPR15MB2999.namprd15.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: 2fb0b57a-45f8-4e6a-da63-08d864bbd66b X-MS-Exchange-CrossTenant-originalarrivaltime: 29 Sep 2020 21:08:39.0820 (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: SdE0KGokiOyWTEZRVVNWgD31yFAFQ7g1uSLcXfB0dHsNPAiDrYMze2F/Mtdo0N+k8V/fWaehfCcIKuIczit08g== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR15MB2406 X-OriginatorOrg: fb.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-09-29_14:2020-09-29,2020-09-29 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxlogscore=999 mlxscore=0 lowpriorityscore=0 suspectscore=0 impostorscore=0 malwarescore=0 phishscore=0 clxscore=1015 bulkscore=0 priorityscore=1501 spamscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009290180 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org > On Sep 29, 2020, at 12:28 PM, Alexei Starovoitov wrote: >=20 > On Tue, Sep 29, 2020 at 12:18 PM Daniel Borkmann w= rote: >>=20 >> On 9/29/20 9:00 PM, Alexei Starovoitov wrote: >>> On Tue, Sep 29, 2020 at 04:02:10PM +0200, Daniel Borkmann wrote: >>>>> + >>>>> +/* Share perf_event among processes */ >>>>> + BPF_F_SHARE_PE =3D (1U << 11), >>>>=20 >>>> nit but given UAPI: maybe name into something more self-descriptive >>>> like BPF_F_SHAREABLE_EVENT ? >>>=20 >>> I'm not happy with either name. >>> It's not about sharing and not really about perf event. >>> I think the current behavior of perf_event_array is unusual and surpris= ing. >>> Sadly we cannot fix it without breaking user space, so flag is needed. >>> How about BPF_F_STICKY_OBJECTS or BPF_F_PRESERVE_OBJECTS >>> or the same with s/OBJECTS/FILES/ ? >>=20 >> Sounds good to me, BPF_F_PRESERVE_OBJECTS or _ENTRIES seems reasonable. >=20 > May be BPF_F_PRESERVE_ELEMENTS? > or _ELEMS ? > I think we refer to map elements more often as elements instead of entrie= s. > But both _entries and _elems work for me. BPF_F_PRESERVE_ELEMS sounds best to me. I will go ahead with it.=20 Thanks, Song=