From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E5ACE18C00 for ; Mon, 12 Jun 2023 09:45:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=uQ/8+qtEwxL57I4UlVvTVvhZ1JibWBOVMl2SE33h5lQ=; b=ZOiq1ke3pot53kQunNRUtXsq1d V5y/hgJbdq0ZCpi19CP5k0s9TVugeElYoMtBjNQiMfKhriDdOViXz13z+mXjhQs1lh5Add+N5EsA+ 97Ytp162GD8DmEyvlIAZDmbyvOg0B9z6LUmK67yAvvHZt5LgJpEb+JZMCr+61gpJu+KOVFSzfR36F 3tqTV1asHS3VYK51N36Uh7QTWlIeQvJ59dJfAYcdLbTUgO2wX/hJw43LbU5N+I998tv53aUMKO5L4 LpWRzwVaRTJBUgMK657xFiLyq8TevHcFHer9zZyt+HcUX4ZJRPRohzv80h606NIyeSXIMh+J++VC2 8w01ss2A==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1q8e0t-002NH2-HK; Mon, 12 Jun 2023 09:39:03 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 52E42303406; 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> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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;