From patchwork Tue May 19 23:29:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anchal Agarwal X-Patchwork-Id: 11559045 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 60760138A for ; Tue, 19 May 2020 23:31:10 +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 3D16F207C4 for ; Tue, 19 May 2020 23:31:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="vIqPsPAp" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3D16F207C4 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 1jbBgM-0006Hg-8h; Tue, 19 May 2020 23:29:58 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jbBgL-0006HF-65 for xen-devel@lists.xenproject.org; Tue, 19 May 2020 23:29:57 +0000 X-Inumbo-ID: a669ce68-9a28-11ea-b07b-bc764e2007e4 Received: from smtp-fw-4101.amazon.com (unknown [72.21.198.25]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id a669ce68-9a28-11ea-b07b-bc764e2007e4; Tue, 19 May 2020 23:29:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1589930997; x=1621466997; h=date:from:to:subject:message-id:references:mime-version: in-reply-to; bh=r7lbs73sfsvJ86GyRkYhd6/aeNxAVZ1wrAJ3MEWq1QM=; b=vIqPsPAplA6WpXtqyybTqMVOdFQYsDFx+OvQzEHCEdTY3aiD7ihfOx59 g+5BMFzLzIVKJIoC8HddpFK/h1w7AKRMg77HKOsDj3+9/F3v4v+Z7Pp9M Zk9x3dzk4C1EP8xfQi0G4jq2PYRjluRTA/stvNspoNmy/5TtEmH7VzYiX 0=; IronPort-SDR: 9zWNpH8TfAOVXYXC65zH0YTjctxGH5l94tqUBCBdTwFQ9nB5vkppYKlmCsdTEitS5G1lbnrQj9 3msnk5oBY8Ww== X-IronPort-AV: E=Sophos;i="5.73,411,1583193600"; d="scan'208";a="31182653" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-2a-d0be17ee.us-west-2.amazon.com) ([10.43.8.6]) by smtp-border-fw-out-4101.iad4.amazon.com with ESMTP; 19 May 2020 23:29:55 +0000 Received: from EX13MTAUEE002.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan3.pdx.amazon.com [10.170.41.166]) by email-inbound-relay-2a-d0be17ee.us-west-2.amazon.com (Postfix) with ESMTPS id 304E8A2003; Tue, 19 May 2020 23:29:53 +0000 (UTC) Received: from EX13D08UEE001.ant.amazon.com (10.43.62.126) by EX13MTAUEE002.ant.amazon.com (10.43.62.24) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 19 May 2020 23:29:40 +0000 Received: from EX13MTAUEE002.ant.amazon.com (10.43.62.24) by EX13D08UEE001.ant.amazon.com (10.43.62.126) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 19 May 2020 23:29:39 +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; Tue, 19 May 2020 23:29:39 +0000 Received: by dev-dsk-anchalag-2a-9c2d1d96.us-west-2.amazon.com (Postfix, from userid 4335130) id 81BF340712; Tue, 19 May 2020 23:29:39 +0000 (UTC) Date: Tue, 19 May 2020 23:29:39 +0000 From: Anchal Agarwal To: , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH 11/12] xen: Update sched clock offset to avoid system instability in hibernation Message-ID: <4066d54951f4ba9437eb0ff6aeb5288fcd20c2fb.1589926004.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 | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c index dae0f74f5390..7e5275944810 100644 --- a/arch/x86/xen/suspend.c +++ b/arch/x86/xen/suspend.c @@ -105,6 +105,8 @@ static int xen_syscore_suspend(void) xen_save_steal_clock(cpu); } + xen_save_sched_clock_offset(); + xrfp.domid = DOMID_SELF; xrfp.gpfn = __pa(HYPERVISOR_shared_info) >> PAGE_SHIFT; @@ -126,6 +128,12 @@ static void xen_syscore_resume(void) pvclock_resume(); + /* + * Restore xen_sched_clock_offset during resume to maintain + * monotonic clock value + */ + xen_restore_sched_clock_offset(); + /* Nonboot CPUs will be resumed when they're brought up */ xen_restore_steal_clock(smp_processor_id());