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=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 2E8D2C4743C for ; Mon, 14 Jun 2021 10:43:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 19C9961879 for ; Mon, 14 Jun 2021 10:43:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232903AbhFNKpr (ORCPT ); Mon, 14 Jun 2021 06:45:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:50058 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233568AbhFNKna (ORCPT ); Mon, 14 Jun 2021 06:43:30 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5E36761437; Mon, 14 Jun 2021 10:36:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1623666961; bh=hWG69ZQ7oXZQhDv+R0Z1/05FRfBv7Ecuh1J/C1TuPJc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S/Z818I4O4lJbYb07OlBmwk1jk4nZKS2QI60nTZwY7he/sjh56KzScwQ454+tjdQC r5nmZxxciEO0yFgKI4YhYPajShhrh4T+e6gSUppcPcBtbgRpCz1xm5IR/iHcATtb1H lyedCtNPGpBNh2ola4XDtsrRCRfyaA4s8X9/y/5Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andi Kleen , Kan Liang , "Peter Zijlstra (Intel)" , Wen Yang Subject: [PATCH 4.19 01/67] perf/core: Fix endless multiplex timer Date: Mon, 14 Jun 2021 12:26:44 +0200 Message-Id: <20210614102643.844029584@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210614102643.797691914@linuxfoundation.org> References: <20210614102643.797691914@linuxfoundation.org> User-Agent: quilt/0.66 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Peter Zijlstra commit 90c91dfb86d0ff545bd329d3ddd72c147e2ae198 upstream. Kan and Andi reported that we fail to kill rotation when the flexible events go empty, but the context does not. XXX moar Fixes: fd7d55172d1e ("perf/cgroups: Don't rotate events for cgroups unnecessarily") Reported-by: Andi Kleen Reported-by: Kan Liang Tested-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Cc: Wen Yang Link: https://lkml.kernel.org/r/20200305123851.GX2596@hirez.programming.kicks-ass.net Signed-off-by: Greg Kroah-Hartman --- kernel/events/core.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2086,6 +2086,7 @@ __perf_remove_from_context(struct perf_e if (!ctx->nr_events && ctx->is_active) { ctx->is_active = 0; + ctx->rotate_necessary = 0; if (ctx->task) { WARN_ON_ONCE(cpuctx->task_ctx != ctx); cpuctx->task_ctx = NULL; @@ -2952,12 +2953,6 @@ static void ctx_sched_out(struct perf_ev if (!ctx->nr_active || !(is_active & EVENT_ALL)) return; - /* - * If we had been multiplexing, no rotations are necessary, now no events - * are active. - */ - ctx->rotate_necessary = 0; - perf_pmu_disable(ctx->pmu); if (is_active & EVENT_PINNED) { list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list) @@ -2967,6 +2962,13 @@ static void ctx_sched_out(struct perf_ev if (is_active & EVENT_FLEXIBLE) { list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list) group_sched_out(event, cpuctx, ctx); + + /* + * Since we cleared EVENT_FLEXIBLE, also clear + * rotate_necessary, is will be reset by + * ctx_flexible_sched_in() when needed. + */ + ctx->rotate_necessary = 0; } perf_pmu_enable(ctx->pmu); } @@ -3705,6 +3707,12 @@ ctx_event_to_rotate(struct perf_event_co typeof(*event), group_node); } + /* + * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in() + * finds there are unschedulable events, it will set it again. + */ + ctx->rotate_necessary = 0; + return event; }