From patchwork Fri Aug 21 22:30:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anchal Agarwal X-Patchwork-Id: 11730733 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2FC3A913 for ; Fri, 21 Aug 2020 22:31:16 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0AB1720738 for ; Fri, 21 Aug 2020 22:31:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="MkCHjZoR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0AB1720738 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=amazon.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k9FYo-0005gq-3J; Fri, 21 Aug 2020 22:30:58 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k9FYm-0005gQ-Dr for xen-devel@lists.xenproject.org; Fri, 21 Aug 2020 22:30:56 +0000 X-Inumbo-ID: 23a791be-77dc-4915-88ab-bddfc92f30fc Received: from smtp-fw-4101.amazon.com (unknown [72.21.198.25]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 23a791be-77dc-4915-88ab-bddfc92f30fc; Fri, 21 Aug 2020 22:30:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1598049056; x=1629585056; h=date:from:to:subject:message-id:references:mime-version: in-reply-to; bh=8mKR6nGsN4/J6yUPoHqgy6Vb/KbDSfcnRfNiku5bjZI=; b=MkCHjZoRmGV1mlt+yZGs3x2eub+6vqYV7SL51xOew2tqzrJGS2u0V+kr rrK7N2dmCUsmzTS4XamKGrcmclnwvIEkjszgY/pYkTEOoHL5OrdBOTWqB LRmGB18keQJhzXKwlIoQMZZThN4SDvrYf1OChaibVvvllOuJH3yM/Vyoi 8=; X-IronPort-AV: E=Sophos;i="5.76,338,1592870400"; d="scan'208";a="49403856" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-1a-af6a10df.us-east-1.amazon.com) ([10.43.8.6]) by smtp-border-fw-out-4101.iad4.amazon.com with ESMTP; 21 Aug 2020 22:30:56 +0000 Received: from EX13MTAUEE002.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan2.iad.amazon.com [10.40.159.162]) by email-inbound-relay-1a-af6a10df.us-east-1.amazon.com (Postfix) with ESMTPS id 51046A22AF; Fri, 21 Aug 2020 22:30:48 +0000 (UTC) Received: from EX13D08UEE002.ant.amazon.com (10.43.62.92) by EX13MTAUEE002.ant.amazon.com (10.43.62.24) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 21 Aug 2020 22:30:29 +0000 Received: from EX13MTAUEE002.ant.amazon.com (10.43.62.24) by EX13D08UEE002.ant.amazon.com (10.43.62.92) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 21 Aug 2020 22:30:29 +0000 Received: from dev-dsk-anchalag-2a-9c2d1d96.us-west-2.amazon.com (172.22.96.68) by mail-relay.amazon.com (10.43.62.224) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Fri, 21 Aug 2020 22:30:29 +0000 Received: by dev-dsk-anchalag-2a-9c2d1d96.us-west-2.amazon.com (Postfix, from userid 4335130) id 1520540362; Fri, 21 Aug 2020 22:30:29 +0000 (UTC) Date: Fri, 21 Aug 2020 22:30:29 +0000 From: Anchal Agarwal To: , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v3 10/11] xen: Update sched clock offset to avoid system instability in hibernation Message-ID: <238e837b8d4e17925801c4e85de17bdfca4ddd00.1598042152.git.anchalag@amazon.com> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Precedence: Bulk X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Save/restore xen_sched_clock_offset in syscore suspend/resume during PM hibernation. Commit '867cefb4cb1012: ("xen: Fix x86 sched_clock() interface for xen")' fixes xen guest time handling during migration. A similar issue is seen during PM hibernation when system runs CPU intensive workload. Post resume pvclock resets the value to 0 however, xen sched_clock_offset is never updated. System instability is seen during resume from hibernation when system is under heavy CPU load. Since xen_sched_clock_offset is not updated, system does not see the monotonic clock value and the scheduler would then think that heavy CPU hog tasks need more time in CPU, causing the system to freeze Signed-off-by: Anchal Agarwal --- arch/x86/xen/suspend.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c index b12db6966af6..a62e08a11681 100644 --- a/arch/x86/xen/suspend.c +++ b/arch/x86/xen/suspend.c @@ -98,8 +98,9 @@ static int xen_syscore_suspend(void) return 0; gnttab_suspend(); - xen_manage_runstate_time(-1); + xen_save_sched_clock_offset(); + xrfp.domid = DOMID_SELF; xrfp.gpfn = __pa(HYPERVISOR_shared_info) >> PAGE_SHIFT; @@ -120,6 +121,12 @@ static void xen_syscore_resume(void) xen_hvm_map_shared_info(); pvclock_resume(); + + /* + * Restore xen_sched_clock_offset during resume to maintain + * monotonic clock value + */ + xen_restore_sched_clock_offset(); xen_manage_runstate_time(0); gnttab_resume(); }