From patchwork Mon Jun 12 09:07:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 13276084 X-Patchwork-Delegate: paul@paul-moore.com 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 D1D8CC83005 for ; Mon, 12 Jun 2023 09:56:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234875AbjFLJ4p (ORCPT ); Mon, 12 Jun 2023 05:56:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60494 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233342AbjFLJyo (ORCPT ); Mon, 12 Jun 2023 05:54:44 -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 9EB964C1B; Mon, 12 Jun 2023 02:39:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; 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=kTQMzLiQOiysp6z8Xt3S6oOFWuHsLtjxBsNekM1iUPM=; b=FnsYw1rgaWsOiA0J8R1O2i1uX3 e/F70Qz8dzTuEl3kifFu3bO7NPhClNyjvgCn8IyOXFExymb1mJLxjsIE1VNsGjM+ZK5UdyD9Uvpmx 8MMlCDrtOaWNKsB/UhUOB/ZOYncIt9ndU2q2e+wO9d2EOd9MKV6zm5aJXolVKFVPXj7clRX/cVNos UIEMW7CktYOkUgJCjntPeUklJKZwTRaqyQxMkh9aZMJURF4j5ZOLong2c9l7tRmNOL8u2yfvD2bky pOzCMpkX6wckfonGJZWPeiND+Om9Xf6BVzQSrlpTGvnF4Bd5KmsJ+mb8KpkZEAGen/+v1YgVnR9df hpzryTVw==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1q8e0n-008kR9-1O; Mon, 12 Jun 2023 09:39:02 +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 446133033BD; Mon, 12 Jun 2023 11:38:53 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id D6BA430A77B71; Mon, 12 Jun 2023 11:38:48 +0200 (CEST) Message-ID: <20230612093540.324593804@infradead.org> User-Agent: quilt/0.66 Date: Mon, 12 Jun 2023 11:07:52 +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 39/57] perf: Simplify perf_event_*_userpage() References: <20230612090713.652690195@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: Signed-off-by: Peter Zijlstra (Intel) --- kernel/events/core.c | 30 ++++++++++-------------------- 1 file changed, 10 insertions(+), 20 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5971,10 +5971,10 @@ static void perf_event_init_userpage(str struct perf_event_mmap_page *userpg; struct perf_buffer *rb; - rcu_read_lock(); + guard(rcu)(); rb = rcu_dereference(event->rb); if (!rb) - goto unlock; + return; userpg = rb->user_page; @@ -5983,9 +5983,6 @@ static void perf_event_init_userpage(str userpg->size = offsetof(struct perf_event_mmap_page, __reserved); userpg->data_offset = PAGE_SIZE; userpg->data_size = perf_data_size(rb); - -unlock: - rcu_read_unlock(); } void __weak arch_perf_update_userpage( @@ -6004,10 +6001,10 @@ void perf_event_update_userpage(struct p struct perf_buffer *rb; u64 enabled, running, now; - rcu_read_lock(); + guard(rcu)(); rb = rcu_dereference(event->rb); if (!rb) - goto unlock; + return; /* * compute total_time_enabled, total_time_running @@ -6025,7 +6022,7 @@ void perf_event_update_userpage(struct p * Disable preemption to guarantee consistent time stamps are stored to * the user page. */ - preempt_disable(); + guard(preempt)(); ++userpg->lock; barrier(); userpg->index = perf_event_index(event); @@ -6043,9 +6040,6 @@ void perf_event_update_userpage(struct p barrier(); ++userpg->lock; - preempt_enable(); -unlock: - rcu_read_unlock(); } EXPORT_SYMBOL_GPL(perf_event_update_userpage); @@ -6061,27 +6055,23 @@ static vm_fault_t perf_mmap_fault(struct return ret; } - rcu_read_lock(); + guard(rcu)(); rb = rcu_dereference(event->rb); if (!rb) - goto unlock; + return ret; if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) - goto unlock; + return ret; vmf->page = perf_mmap_to_page(rb, vmf->pgoff); if (!vmf->page) - goto unlock; + return ret; get_page(vmf->page); vmf->page->mapping = vmf->vma->vm_file->f_mapping; vmf->page->index = vmf->pgoff; - ret = 0; -unlock: - rcu_read_unlock(); - - return ret; + return 0; } static void ring_buffer_attach(struct perf_event *event,