From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 63863C433E3 for ; Wed, 19 Aug 2020 08:55:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3B6C52072D for ; Wed, 19 Aug 2020 08:55:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Wz6rFRXo"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="QzUYsdUH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727878AbgHSIzo (ORCPT ); Wed, 19 Aug 2020 04:55:44 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:37136 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726972AbgHSIwK (ORCPT ); Wed, 19 Aug 2020 04:52:10 -0400 Date: Wed, 19 Aug 2020 08:52:07 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1597827128; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cSB0N+9be3Ueq42H1CGqA3pI7bdNN9hhiVSr6xoOjiI=; b=Wz6rFRXoLc3SwnuLqS1fByUGIy+EoPw2lHJPYlGNudUgf2n54RpHvxlQPyqUZoV99+qnQ9 FMBOtkKedfSqv1oDZ9Ov6hSLK9mNWyrC1xIuF9Snal48cHfxo9iTuO8u4R+ZodySO9LVSx 3x1pFaYTp9oDNvrsF8Eg6efXqsDZkMyNPrSvmlkYPDXABRUNoCa81hepl4DHRAkto2Ub1T RJUSkKXDxFh3BGLXQYM2oeBz/JZBEq/acG10/D8Hc0PrGZw7JYJJHhmE2W0zrMfdkcCOvZ ic4R4vMb/wFA8MEW6pfGqDLYnqXZUNOw2fW0Js8R88tmL3cN5STmZnNkjki5xQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1597827128; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cSB0N+9be3Ueq42H1CGqA3pI7bdNN9hhiVSr6xoOjiI=; b=QzUYsdUHDO9ArO6OFldMA+iafllNBo1UlevEnhnoknv5zmwjtbEK98GSEIZ3sU7D2HZxto /uL+++Hp91shJGBA== From: "tip-bot2 for Kan Liang" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: perf/core] perf/core: Add a new PERF_EV_CAP_SIBLING event capability Cc: Peter Zijlstra , Kan Liang , x86 , LKML In-Reply-To: <20200723171117.9918-8-kan.liang@linux.intel.com> References: <20200723171117.9918-8-kan.liang@linux.intel.com> MIME-Version: 1.0 Message-ID: <159782712765.3192.11418251021976454957.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the perf/core branch of tip: Commit-ID: 9f0c4fa111dc909ca545c45ea20ec84da555ce16 Gitweb: https://git.kernel.org/tip/9f0c4fa111dc909ca545c45ea20ec84da555ce16 Author: Kan Liang AuthorDate: Thu, 23 Jul 2020 10:11:10 -07:00 Committer: Peter Zijlstra CommitterDate: Tue, 18 Aug 2020 16:34:36 +02:00 perf/core: Add a new PERF_EV_CAP_SIBLING event capability Current perf assumes that events in a group are independent. Close an event doesn't impact the value of the other events in the same group. If the closed event is a member, after the event closure, other events are still running like a group. If the closed event is a leader, other events are running as singleton events. Add PERF_EV_CAP_SIBLING to allow events to indicate they require being part of a group, and when the leader dies they cannot exist independently. Suggested-by: Peter Zijlstra Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200723171117.9918-8-kan.liang@linux.intel.com --- include/linux/perf_event.h | 4 ++++- kernel/events/core.c | 38 ++++++++++++++++++++++++++++++++----- 2 files changed, 37 insertions(+), 5 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 04a49cc..6048650 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -576,9 +576,13 @@ typedef void (*perf_overflow_handler_t)(struct perf_event *, * PERF_EV_CAP_SOFTWARE: Is a software event. * PERF_EV_CAP_READ_ACTIVE_PKG: A CPU event (or cgroup event) that can be read * from any CPU in the package where it is active. + * PERF_EV_CAP_SIBLING: An event with this flag must be a group sibling and + * cannot be a group leader. If an event with this flag is detached from the + * group it is scheduled out and moved into an unrecoverable ERROR state. */ #define PERF_EV_CAP_SOFTWARE BIT(0) #define PERF_EV_CAP_READ_ACTIVE_PKG BIT(1) +#define PERF_EV_CAP_SIBLING BIT(2) #define SWEVENT_HLIST_BITS 8 #define SWEVENT_HLIST_SIZE (1 << SWEVENT_HLIST_BITS) diff --git a/kernel/events/core.c b/kernel/events/core.c index 5bfe8e3..57efe3b 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2133,8 +2133,24 @@ static inline struct list_head *get_event_list(struct perf_event *event) return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active; } +/* + * Events that have PERF_EV_CAP_SIBLING require being part of a group and + * cannot exist on their own, schedule them out and move them into the ERROR + * state. Also see _perf_event_enable(), it will not be able to recover + * this ERROR state. + */ +static inline void perf_remove_sibling_event(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); + + event_sched_out(event, cpuctx, ctx); + perf_event_set_state(event, PERF_EVENT_STATE_ERROR); +} + static void perf_group_detach(struct perf_event *event) { + struct perf_event *leader = event->group_leader; struct perf_event *sibling, *tmp; struct perf_event_context *ctx = event->ctx; @@ -2153,7 +2169,7 @@ static void perf_group_detach(struct perf_event *event) /* * If this is a sibling, remove it from its group. */ - if (event->group_leader != event) { + if (leader != event) { list_del_init(&event->sibling_list); event->group_leader->nr_siblings--; goto out; @@ -2166,6 +2182,9 @@ static void perf_group_detach(struct perf_event *event) */ list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) { + if (sibling->event_caps & PERF_EV_CAP_SIBLING) + perf_remove_sibling_event(sibling); + sibling->group_leader = sibling; list_del_init(&sibling->sibling_list); @@ -2183,10 +2202,10 @@ static void perf_group_detach(struct perf_event *event) } out: - perf_event__header_size(event->group_leader); - - for_each_sibling_event(tmp, event->group_leader) + for_each_sibling_event(tmp, leader) perf_event__header_size(tmp); + + perf_event__header_size(leader); } static bool is_orphaned_event(struct perf_event *event) @@ -2979,6 +2998,7 @@ static void _perf_event_enable(struct perf_event *event) raw_spin_lock_irq(&ctx->lock); if (event->state >= PERF_EVENT_STATE_INACTIVE || event->state < PERF_EVENT_STATE_ERROR) { +out: raw_spin_unlock_irq(&ctx->lock); return; } @@ -2990,8 +3010,16 @@ static void _perf_event_enable(struct perf_event *event) * has gone back into error state, as distinct from the task having * been scheduled away before the cross-call arrived. */ - if (event->state == PERF_EVENT_STATE_ERROR) + if (event->state == PERF_EVENT_STATE_ERROR) { + /* + * Detached SIBLING events cannot leave ERROR state. + */ + if (event->event_caps & PERF_EV_CAP_SIBLING && + event->group_leader == event) + goto out; + event->state = PERF_EVENT_STATE_OFF; + } raw_spin_unlock_irq(&ctx->lock); event_function_call(event, __perf_event_enable, NULL);