From patchwork Thu Jun 6 07:02:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wei Wang X-Patchwork-Id: 10978787 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8F3D992A for ; Thu, 6 Jun 2019 07:45:26 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8499920564 for ; Thu, 6 Jun 2019 07:45:26 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 788E3287FB; Thu, 6 Jun 2019 07:45:26 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id ED80427FB1 for ; Thu, 6 Jun 2019 07:45:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727113AbfFFHpR (ORCPT ); Thu, 6 Jun 2019 03:45:17 -0400 Received: from mga01.intel.com ([192.55.52.88]:25012 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726976AbfFFHoq (ORCPT ); Thu, 6 Jun 2019 03:44:46 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Jun 2019 00:44:41 -0700 X-ExtLoop1: 1 Received: from devel-ww.sh.intel.com ([10.239.48.128]) by orsmga005.jf.intel.com with ESMTP; 06 Jun 2019 00:44:38 -0700 From: Wei Wang To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, pbonzini@redhat.com, ak@linux.intel.com, peterz@infradead.org Cc: kan.liang@intel.com, mingo@redhat.com, rkrcmar@redhat.com, like.xu@intel.com, wei.w.wang@intel.com, jannh@google.com, arei.gonglei@huawei.com, jmattson@google.com Subject: [PATCH v6 07/12] perf/x86: no counter allocation support Date: Thu, 6 Jun 2019 15:02:26 +0800 Message-Id: <1559804551-42271-8-git-send-email-wei.w.wang@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1559804551-42271-1-git-send-email-wei.w.wang@intel.com> References: <1559804551-42271-1-git-send-email-wei.w.wang@intel.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In some cases, an event may be created without needing a counter allocation. For example, an lbr event may be created by the host only to help save/restore the lbr stack on the vCPU context switching. This patch adds a new interface to allow users to create a perf event without the need of counter assignment. Signed-off-by: Wei Wang Cc: Andi Kleen Cc: Peter Zijlstra --- arch/x86/events/core.c | 12 ++++++++++++ include/linux/perf_event.h | 13 +++++++++++++ kernel/events/core.c | 37 +++++++++++++++++++++++++------------ 3 files changed, 50 insertions(+), 12 deletions(-) diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index f315425..eebbd65 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -410,6 +410,9 @@ int x86_setup_perfctr(struct perf_event *event) struct hw_perf_event *hwc = &event->hw; u64 config; + if (is_no_counter_event(event)) + return 0; + if (!is_sampling_event(event)) { hwc->sample_period = x86_pmu.max_period; hwc->last_period = hwc->sample_period; @@ -1248,6 +1251,12 @@ static int x86_pmu_add(struct perf_event *event, int flags) hwc = &event->hw; n0 = cpuc->n_events; + + if (is_no_counter_event(event)) { + n = n0; + goto done_collect; + } + ret = n = collect_events(cpuc, event, false); if (ret < 0) goto out; @@ -1422,6 +1431,9 @@ static void x86_pmu_del(struct perf_event *event, int flags) if (cpuc->txn_flags & PERF_PMU_TXN_ADD) goto do_del; + if (is_no_counter_event(event)) + goto do_del; + /* * Not a TXN, therefore cleanup properly. */ diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 0ab99c7..19e6593 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -528,6 +528,7 @@ typedef void (*perf_overflow_handler_t)(struct perf_event *, */ #define PERF_EV_CAP_SOFTWARE BIT(0) #define PERF_EV_CAP_READ_ACTIVE_PKG BIT(1) +#define PERF_EV_CAP_NO_COUNTER BIT(2) #define SWEVENT_HLIST_BITS 8 #define SWEVENT_HLIST_SIZE (1 << SWEVENT_HLIST_BITS) @@ -895,6 +896,13 @@ extern int perf_event_refresh(struct perf_event *event, int refresh); extern void perf_event_update_userpage(struct perf_event *event); extern int perf_event_release_kernel(struct perf_event *event); extern struct perf_event * +perf_event_create(struct perf_event_attr *attr, + int cpu, + struct task_struct *task, + perf_overflow_handler_t overflow_handler, + void *context, + bool counter_assignment); +extern struct perf_event * perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, struct task_struct *task, @@ -1032,6 +1040,11 @@ static inline bool is_sampling_event(struct perf_event *event) return event->attr.sample_period != 0; } +static inline bool is_no_counter_event(struct perf_event *event) +{ + return !!(event->event_caps & PERF_EV_CAP_NO_COUNTER); +} + /* * Return 1 for a software event, 0 for a hardware event */ diff --git a/kernel/events/core.c b/kernel/events/core.c index abbd4b3..70884df 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11162,18 +11162,10 @@ SYSCALL_DEFINE5(perf_event_open, return err; } -/** - * perf_event_create_kernel_counter - * - * @attr: attributes of the counter to create - * @cpu: cpu in which the counter is bound - * @task: task to profile (NULL for percpu) - */ -struct perf_event * -perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, - struct task_struct *task, - perf_overflow_handler_t overflow_handler, - void *context) +struct perf_event *perf_event_create(struct perf_event_attr *attr, int cpu, + struct task_struct *task, + perf_overflow_handler_t overflow_handler, + void *context, bool need_counter) { struct perf_event_context *ctx; struct perf_event *event; @@ -11193,6 +11185,9 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, /* Mark owner so we could distinguish it from user events. */ event->owner = TASK_TOMBSTONE; + if (!need_counter) + event->event_caps |= PERF_EV_CAP_NO_COUNTER; + ctx = find_get_context(event->pmu, task, event); if (IS_ERR(ctx)) { err = PTR_ERR(ctx); @@ -11241,6 +11236,24 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, err: return ERR_PTR(err); } +EXPORT_SYMBOL_GPL(perf_event_create); + +/** + * perf_event_create_kernel_counter + * + * @attr: attributes of the counter to create + * @cpu: cpu in which the counter is bound + * @task: task to profile (NULL for percpu) + */ +struct perf_event * +perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, + struct task_struct *task, + perf_overflow_handler_t overflow_handler, + void *context) +{ + return perf_event_create(attr, cpu, task, overflow_handler, + context, true); +} EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)