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Wed, 6 Aug 2025 11:42:31 GMT Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C2DF420043; Wed, 6 Aug 2025 11:42:31 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 17CBC20040; Wed, 6 Aug 2025 11:42:31 +0000 (GMT) Received: from heavy.ibm.com (unknown [9.111.29.38]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 6 Aug 2025 11:42:31 +0000 (GMT) From: Ilya Leoshkevich To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Ian Rogers , Arnaldo Carvalho de Melo Cc: bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, Thomas Richter , Jiri Olsa , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Ilya Leoshkevich , Eduard Zingerman Subject: [PATCH v4 1/2] libbpf: Add the ability to suppress perf event enablement Date: Wed, 6 Aug 2025 13:40:34 +0200 Message-ID: <20250806114227.14617-2-iii@linux.ibm.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250806114227.14617-1-iii@linux.ibm.com> References: <20250806114227.14617-1-iii@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: RjeSZbbjwwvN4eaYsdbq3rCoyu36mHDg X-Proofpoint-ORIG-GUID: 4Q29_vahi6Xz3ZMX2B2MrAa5Xq1-mKvT X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwODA2MDA3MSBTYWx0ZWRfX15si+6XF8fVZ 9fRWgbfiFD+3QAmQgF1o1tcMONzhIVqMxgQOAFqudKLcccII3heufS8KIR4AyY3F8hlbUXjly/j Lb/PzBt1pOmBCpUU4TdzhtwZVW16tae2uedXOsqPX4EWez/9k7a870VXLR6RxuPVcRiMGAsuYpJ SH0N6eWnEXyVe50a88Py+qnY7KOaIL0o99xg+6mlwODWd6azI2TkO9Fv66ca7USLZEutnHQ66rg iPNF6NMq8qikUX8Gr1fanPC64Ww+nNjwetptQWZryGii1WwfOxgBMnZAzFFVKNcOjUZtFQ/0QCC fWM1ncztNJJ6AoVCaMQSLtUb2Glcik6dkBmmol5WmU2+s6/PzSgewitEm3hn3rBpMOdqADKo40N r2LZU+mvo1Zo4i7G1xl/eI0jzx4Uu/zzkHmcP3ZMQSzdHikGhDlqnLbQfThoTC7SNQ3wB2US X-Authority-Analysis: v=2.4 cv=TayWtQQh c=1 sm=1 tr=0 ts=68933fac cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=2OwXVqhp2XgA:10 a=pGLkceISAAAA:8 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=TeCzLofx3L-FRdGKzo8A:9 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-08-06_03,2025-08-06_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 adultscore=0 phishscore=0 impostorscore=0 spamscore=0 mlxlogscore=996 bulkscore=0 priorityscore=1501 mlxscore=0 lowpriorityscore=0 malwarescore=0 clxscore=1015 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2507300000 definitions=main-2508060071 Automatically enabling a perf event after attaching a BPF prog to it is not always desirable. Add a new no_ioctl_enable field to struct bpf_perf_event_opts. While introducing ioctl_enable instead would be nicer in that it would avoid a double negation in the implementation, it would make DECLARE_LIBBPF_OPTS() less efficient. Acked-by: Eduard Zingerman Suggested-by: Jiri Olsa Tested-by: Thomas Richter Co-developed-by: Thomas Richter Signed-off-by: Thomas Richter Signed-off-by: Ilya Leoshkevich --- tools/lib/bpf/libbpf.c | 13 ++++++++----- tools/lib/bpf/libbpf.h | 4 +++- 2 files changed, 11 insertions(+), 6 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index fb4d92c5c339..8f5a81b672e1 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -10965,11 +10965,14 @@ struct bpf_link *bpf_program__attach_perf_event_opts(const struct bpf_program *p } link->link.fd = pfd; } - if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) { - err = -errno; - pr_warn("prog '%s': failed to enable perf_event FD %d: %s\n", - prog->name, pfd, errstr(err)); - goto err_out; + + if (!OPTS_GET(opts, dont_enable, false)) { + if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) { + err = -errno; + pr_warn("prog '%s': failed to enable perf_event FD %d: %s\n", + prog->name, pfd, errstr(err)); + goto err_out; + } } return &link->link; diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index d1cf813a057b..455a957cb702 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -499,9 +499,11 @@ struct bpf_perf_event_opts { __u64 bpf_cookie; /* don't use BPF link when attach BPF program */ bool force_ioctl_attach; + /* don't automatically enable the event */ + bool dont_enable; size_t :0; }; -#define bpf_perf_event_opts__last_field force_ioctl_attach +#define bpf_perf_event_opts__last_field dont_enable LIBBPF_API struct bpf_link * bpf_program__attach_perf_event(const struct bpf_program *prog, int pfd); -- 2.50.1