From patchwork Mon Jun 12 09:07:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 13276206 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD98CC87FE1 for ; Mon, 12 Jun 2023 09:56:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235824AbjFLJ4d (ORCPT ); Mon, 12 Jun 2023 05:56:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33436 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234058AbjFLJyv (ORCPT ); Mon, 12 Jun 2023 05:54:51 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C93D5122; Mon, 12 Jun 2023 02:39:20 -0700 (PDT) DKIM-Signature: v=1; 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Mon, 12 Jun 2023 11:38:53 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id F2AAD30A77B78; Mon, 12 Jun 2023 11:38:48 +0200 (CEST) Message-ID: <20230612093540.708955479@infradead.org> User-Agent: quilt/0.66 Date: Mon, 12 Jun 2023 11:07:57 +0200 From: Peter Zijlstra To: torvalds@linux-foundation.org, keescook@chromium.org, gregkh@linuxfoundation.org, pbonzini@redhat.com Cc: masahiroy@kernel.org, nathan@kernel.org, ndesaulniers@google.com, nicolas@fjasle.eu, catalin.marinas@arm.com, will@kernel.org, vkoul@kernel.org, trix@redhat.com, ojeda@kernel.org, peterz@infradead.org, mingo@redhat.com, longman@redhat.com, boqun.feng@gmail.com, dennis@kernel.org, tj@kernel.org, cl@linux.com, acme@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, namhyung@kernel.org, irogers@google.com, adrian.hunter@intel.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, paulmck@kernel.org, frederic@kernel.org, quic_neeraju@quicinc.com, joel@joelfernandes.org, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, rientjes@google.com, vbabka@suse.cz, roman.gushchin@linux.dev, 42.hyeyoo@gmail.com, apw@canonical.com, joe@perches.com, dwaipayanray1@gmail.com, lukas.bulwahn@gmail.com, john.johansen@canonical.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, llvm@lists.linux.dev, linux-perf-users@vger.kernel.org, rcu@vger.kernel.org, linux-security-module@vger.kernel.org, tglx@linutronix.de, ravi.bangoria@amd.com, error27@gmail.com, luc.vanoostenryck@gmail.com Subject: [PATCH v3 44/57] perf: Simplify bpf_overflow_handler() References: <20230612090713.652690195@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Signed-off-by: Peter Zijlstra (Intel) --- kernel/events/core.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -10288,16 +10288,14 @@ static void bpf_overflow_handler(struct int ret = 0; ctx.regs = perf_arch_bpf_user_pt_regs(regs); - if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) - goto out; - rcu_read_lock(); - prog = READ_ONCE(event->prog); - if (prog) { - perf_prepare_sample(data, event, regs); - ret = bpf_prog_run(prog, &ctx); + if (likely(__this_cpu_inc_return(bpf_prog_active) == 1)) { + guard(rcu)(); + prog = READ_ONCE(event->prog); + if (prog) { + perf_prepare_sample(data, event, regs); + ret = bpf_prog_run(prog, &ctx); + } } - rcu_read_unlock(); -out: __this_cpu_dec(bpf_prog_active); if (!ret) return;