From patchwork Mon Jun 12 09:08:08 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 13276161 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 C9A3DC7EE25 for ; Mon, 12 Jun 2023 09:57:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230302AbjFLJ5f (ORCPT ); Mon, 12 Jun 2023 05:57:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33442 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234182AbjFLJyw (ORCPT ); Mon, 12 Jun 2023 05:54:52 -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 3A8864C19; Mon, 12 Jun 2023 02:39:22 -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 3757230A79088; Mon, 12 Jun 2023 11:38:49 +0200 (CEST) Message-ID: <20230612093541.524967360@infradead.org> User-Agent: quilt/0.66 Date: Mon, 12 Jun 2023 11:08:08 +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 55/57] perf: Simplify find_get_context() References: <20230612090713.652690195@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org Signed-off-by: Peter Zijlstra (Intel) --- kernel/events/core.c | 46 ++++++++++++++++++---------------------------- 1 file changed, 18 insertions(+), 28 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1202,6 +1202,8 @@ static void put_ctx(struct perf_event_co } } +DEFINE_FREE(put_ctx, struct perf_event_context *, if (_T) put_ctx(_T)) + /* * Because of perf_event::ctx migration in sys_perf_event_open::move_group and * perf_pmu_migrate_context() we need some magic. @@ -4718,41 +4720,29 @@ find_get_context(struct task_struct *tas if (clone_ctx) put_ctx(clone_ctx); } else { - ctx = alloc_perf_context(task); - err = -ENOMEM; - if (!ctx) - goto errout; - - err = 0; - mutex_lock(&task->perf_event_mutex); - /* - * If it has already passed perf_event_exit_task(). - * we must see PF_EXITING, it takes this mutex too. - */ - if (task->flags & PF_EXITING) - err = -ESRCH; - else if (task->perf_event_ctxp) - err = -EAGAIN; - else { - get_ctx(ctx); - ++ctx->pin_count; - rcu_assign_pointer(task->perf_event_ctxp, ctx); - } - mutex_unlock(&task->perf_event_mutex); + struct perf_event_context *new __free(put_ctx) = + alloc_perf_context(task); + if (!new) + return ERR_PTR(-ENOMEM); - if (unlikely(err)) { - put_ctx(ctx); + scoped_guard (mutex, &task->perf_event_mutex) { + /* + * If it has already passed perf_event_exit_task(). + * we must see PF_EXITING, it takes this mutex too. + */ + if (task->flags & PF_EXITING) + return ERR_PTR(-ESRCH); - if (err == -EAGAIN) + if (task->perf_event_ctxp) goto retry; - goto errout; + + ctx = get_ctx(no_free_ptr(new)); + ++ctx->pin_count; + rcu_assign_pointer(task->perf_event_ctxp, ctx); } } return ctx; - -errout: - return ERR_PTR(err); } DEFINE_CLASS(find_get_ctx, struct perf_event_context *,