From patchwork Fri Aug 21 22:25:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anchal Agarwal X-Patchwork-Id: 256982 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=-11.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 3636BC433E3 for ; Fri, 21 Aug 2020 22:26:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0DF062076E for ; Fri, 21 Aug 2020 22:26:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="Ig431mc8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726747AbgHUW0B (ORCPT ); Fri, 21 Aug 2020 18:26:01 -0400 Received: from smtp-fw-2101.amazon.com ([72.21.196.25]:15381 "EHLO smtp-fw-2101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726761AbgHUW0A (ORCPT ); Fri, 21 Aug 2020 18:26:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1598048760; x=1629584760; h=date:from:to:subject:message-id:references:mime-version: in-reply-to; bh=P6c+ghbxBFW6FKLFXMggDpsPZB1htB1D5l7v91pDUP4=; b=Ig431mc8nkL7A2MVUhWBPacrSyQ+W4gVssi6yw6WUQTFR00KxbUYfSEJ bBNll5FaRaUMO5TOqXtvye6SAqBu2NJzWumWb3wuXT7f4N/u5fsF0D7J8 9/oh2CQz2KfRvXKiniguHk+6c2+s5QwCeTtQBUrgpZ5nyYMWhEFxrQ5ti c=; X-IronPort-AV: E=Sophos;i="5.76,338,1592870400"; d="scan'208";a="49215629" Received: from iad12-co-svc-p1-lb1-vlan2.amazon.com (HELO email-inbound-relay-1a-7d76a15f.us-east-1.amazon.com) ([10.43.8.2]) by smtp-border-fw-out-2101.iad2.amazon.com with ESMTP; 21 Aug 2020 22:25:58 +0000 Received: from EX13MTAUEE002.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan3.iad.amazon.com [10.40.159.166]) by email-inbound-relay-1a-7d76a15f.us-east-1.amazon.com (Postfix) with ESMTPS id B7A6CA2891; Fri, 21 Aug 2020 22:25:50 +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; Fri, 21 Aug 2020 22:25:50 +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; Fri, 21 Aug 2020 22:25:49 +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 22:25:49 +0000 Received: by dev-dsk-anchalag-2a-9c2d1d96.us-west-2.amazon.com (Postfix, from userid 4335130) id 6AD8840362; Fri, 21 Aug 2020 22:25:49 +0000 (UTC) Date: Fri, 21 Aug 2020 22:25:49 +0000 From: Anchal Agarwal To: , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v3 01/11] xen/manage: keep track of the on-going suspend mode Message-ID: <9b970e12491107afda0c1d4a6f154b52d90346ac.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) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Munehisa Kamata Guest hibernation is different from xen suspend/resume/live migration. Xen save/restore does not use pm_ops as is needed by guest hibernation. Hibernation in guest follows ACPI path and is guest inititated , the hibernation image is saved within guest as compared to later modes which are xen toolstack assisted and image creation/storage is in control of hypervisor/host machine. To differentiate between Xen suspend and PM hibernation, keep track of the on-going suspend mode by mainly using a new API to keep track of SHUTDOWN_SUSPEND state. Introduce a simple function that keeps track of on-going suspend mode so that PM hibernation code can behave differently according to the current suspend mode. Since Xen suspend doesn't have corresponding PM event, its main logic is modfied to acquire pm_mutex. Though, accquirng pm_mutex is still right thing to do, we may see deadlock if PM hibernation is interrupted by Xen suspend. PM hibernation depends on xenwatch thread to process xenbus state transactions, but the thread will sleep to wait pm_mutex which is already held by PM hibernation context in the scenario. Xen shutdown code may need some changes to avoid the issue. [Anchal Agarwal: Changelog]: RFC v1->v2: Code refactoring v1->v2: Remove unused functions for PM SUSPEND/PM hibernation v2->v3: Added logic to use existing pm_notifier to detect for ARM and abort hibernation for ARM guests. Also removed different suspend_modes and simplified the code with using existing state variables for tracking Xen suspend. The notifier won't get registered for pvh dom0 either. Signed-off-by: Anchal Agarwal Signed-off-by: Munehisa Kamata --- drivers/xen/manage.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ include/xen/xen-ops.h | 1 + 2 files changed, 47 insertions(+) diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c index cd046684e0d1..d2a51c454c3e 100644 --- a/drivers/xen/manage.c +++ b/drivers/xen/manage.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include @@ -40,6 +41,11 @@ enum shutdown_state { /* Ignore multiple shutdown requests. */ static enum shutdown_state shutting_down = SHUTDOWN_INVALID; +bool is_xen_suspend(void) +{ + return shutting_down == SHUTDOWN_SUSPEND; +} + struct suspend_info { int cancelled; }; @@ -99,6 +105,8 @@ static void do_suspend(void) int err; struct suspend_info si; + lock_system_sleep(); + shutting_down = SHUTDOWN_SUSPEND; err = freeze_processes(); @@ -162,6 +170,8 @@ static void do_suspend(void) thaw_processes(); out: shutting_down = SHUTDOWN_INVALID; + + unlock_system_sleep(); } #endif /* CONFIG_HIBERNATE_CALLBACKS */ @@ -387,3 +397,39 @@ int xen_setup_shutdown_event(void) EXPORT_SYMBOL_GPL(xen_setup_shutdown_event); subsys_initcall(xen_setup_shutdown_event); + +static int xen_pm_notifier(struct notifier_block *notifier, + unsigned long pm_event, void *unused) +{ + int ret; + + switch (pm_event) { + case PM_SUSPEND_PREPARE: + case PM_HIBERNATION_PREPARE: + /* Guest hibernation is not supported for aarch64 currently*/ + if (IS_ENABLED(CONFIG_ARM64)) { + ret = NOTIFY_BAD; + break; + } + case PM_RESTORE_PREPARE: + case PM_POST_SUSPEND: + case PM_POST_HIBERNATION: + case PM_POST_RESTORE: + default: + ret = NOTIFY_OK; + } + return ret; +}; + +static struct notifier_block xen_pm_notifier_block = { + .notifier_call = xen_pm_notifier +}; + +static int xen_setup_pm_notifier(void) +{ + if (!xen_hvm_domain() || xen_initial_domain()) + return -ENODEV; + return register_pm_notifier(&xen_pm_notifier_block); +} + +subsys_initcall(xen_setup_pm_notifier); diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h index 39a5580f8feb..e8b08734fab1 100644 --- a/include/xen/xen-ops.h +++ b/include/xen/xen-ops.h @@ -40,6 +40,7 @@ u64 xen_steal_clock(int cpu); int xen_setup_shutdown_event(void); +bool is_xen_suspend(void); extern unsigned long *xen_contiguous_bitmap; #if defined(CONFIG_XEN_PV) || defined(CONFIG_ARM) || defined(CONFIG_ARM64) From patchwork Fri Aug 21 22:27:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anchal Agarwal X-Patchwork-Id: 256981 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=-11.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 6B83EC433DF for ; Fri, 21 Aug 2020 22:27:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 498992076E for ; 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21 Aug 2020 22:27:34 +0000 Received: from EX13MTAUWB001.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan3.pdx.amazon.com [10.170.41.166]) by email-inbound-relay-2c-579b7f5b.us-west-2.amazon.com (Postfix) with ESMTPS id AA474A2B36; Fri, 21 Aug 2020 22:27:32 +0000 (UTC) Received: from EX13D05UWB003.ant.amazon.com (10.43.161.26) by EX13MTAUWB001.ant.amazon.com (10.43.161.207) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 21 Aug 2020 22:27:26 +0000 Received: from EX13MTAUWB001.ant.amazon.com (10.43.161.207) by EX13D05UWB003.ant.amazon.com (10.43.161.26) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 21 Aug 2020 22:27:25 +0000 Received: from dev-dsk-anchalag-2a-9c2d1d96.us-west-2.amazon.com (172.22.96.68) by mail-relay.amazon.com (10.43.161.249) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Fri, 21 Aug 2020 22:27:25 +0000 Received: by dev-dsk-anchalag-2a-9c2d1d96.us-west-2.amazon.com (Postfix, from userid 4335130) id E96BE40362; Fri, 21 Aug 2020 22:27:25 +0000 (UTC) Date: Fri, 21 Aug 2020 22:27:25 +0000 From: Anchal Agarwal To: , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v3 04/11] x86/xen: add system core suspend and resume callbacks Message-ID: <6b86a4bf71ee3e3e9b0bb00f594a4edc85da19a9.1598042152.git.anchalag@amazon.com> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Munehisa Kamata Add Xen PVHVM specific system core callbacks for PM hibernation support. The callbacks suspend and resume Xen primitives like shared_info, pvclock and grant table. These syscore_ops are specifically for domU hibernation. xen_suspend() calls syscore_suspend() during Xen suspend operation however, during xen suspend lock_system_sleep() lock is taken and thus system cannot trigger hibernation. These system core callbacks will be called only from the hibernation context. [Anchal Agarwal: Changelog]: v1->v2: Edit commit message Fixed syscore_suspend() to call gnntab_suspend Removed suspend mode check in syscore_suspend()/ syscore_resume() v2->v3: Re-introduced check for xen suspend mode to avoid syscore osp callbacks getting executed during xen suspend/resume Signed-off-by: Agarwal Anchal Signed-off-by: Munehisa Kamata --- arch/x86/xen/enlighten_hvm.c | 1 + arch/x86/xen/suspend.c | 55 ++++++++++++++++++++++++++++++++++++++++++++ include/xen/xen-ops.h | 2 ++ 3 files changed, 58 insertions(+) diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c index ff7c69278f63..4b6ad30106dd 100644 --- a/arch/x86/xen/enlighten_hvm.c +++ b/arch/x86/xen/enlighten_hvm.c @@ -216,6 +216,7 @@ static void __init xen_hvm_guest_init(void) if (xen_feature(XENFEAT_hvm_callback_vector)) xen_have_vector_callback = 1; + xen_setup_syscore_ops(); xen_hvm_smp_init(); WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_hvm, xen_cpu_dead_hvm)); xen_unplug_emulated_devices(); diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c index 1d83152c761b..550aa0fc9465 100644 --- a/arch/x86/xen/suspend.c +++ b/arch/x86/xen/suspend.c @@ -2,17 +2,22 @@ #include #include #include +#include +#include #include #include +#include #include #include +#include #include #include #include #include #include +#include #include "xen-ops.h" #include "mmu.h" @@ -82,3 +87,53 @@ void xen_arch_suspend(void) on_each_cpu(xen_vcpu_notify_suspend, NULL, 1); } + +static int xen_syscore_suspend(void) +{ + struct xen_remove_from_physmap xrfp; + int ret; + + /* Xen suspend does similar stuffs in its own logic */ + if (is_xen_suspend()) + return 0; + + gnttab_suspend(); + + xrfp.domid = DOMID_SELF; + xrfp.gpfn = __pa(HYPERVISOR_shared_info) >> PAGE_SHIFT; + + ret = HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrfp); + if (!ret) + HYPERVISOR_shared_info = &xen_dummy_shared_info; + + return ret; +} + +static void xen_syscore_resume(void) +{ + /* Xen suspend does similar stuffs in its own logic */ + if (is_xen_suspend()) + return; + + /* No need to setup vcpu_info as it's already moved off */ + xen_hvm_map_shared_info(); + + pvclock_resume(); + + gnttab_resume(); +} + +/* + * These callbacks will be called with interrupts disabled and when having only + * one CPU online. + */ +static struct syscore_ops xen_hvm_syscore_ops = { + .suspend = xen_syscore_suspend, + .resume = xen_syscore_resume +}; + +void __init xen_setup_syscore_ops(void) +{ + if (xen_hvm_domain()) + register_syscore_ops(&xen_hvm_syscore_ops); +} diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h index e8b08734fab1..bad334cd55d7 100644 --- a/include/xen/xen-ops.h +++ b/include/xen/xen-ops.h @@ -41,6 +41,8 @@ u64 xen_steal_clock(int cpu); int xen_setup_shutdown_event(void); bool is_xen_suspend(void); +void xen_setup_syscore_ops(void); + extern unsigned long *xen_contiguous_bitmap; #if defined(CONFIG_XEN_PV) || defined(CONFIG_ARM) || defined(CONFIG_ARM64) From patchwork Fri Aug 21 22:28:19 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anchal Agarwal X-Patchwork-Id: 256980 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=-11.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_SANE_1 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 27910C433DF for ; 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Fri, 21 Aug 2020 22:28:19 +0000 Received: by dev-dsk-anchalag-2a-9c2d1d96.us-west-2.amazon.com (Postfix, from userid 4335130) id 82B9740362; Fri, 21 Aug 2020 22:28:19 +0000 (UTC) Date: Fri, 21 Aug 2020 22:28:19 +0000 From: Anchal Agarwal To: , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v3 06/11] xen-blkfront: add callbacks for PM suspend and hibernation Message-ID: <22b8e0d0c2a5a7b7755d5f0206aa8de61537c5c3.1598042152.git.anchalag@amazon.com> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Munehisa Kamata S4 power transisiton states are much different than xen suspend/resume. Former is visible to the guest and frontend drivers should be aware of the state transistions and should be able to take appropriate actions when needed. In transition to S4 we need to make sure that at least all the in-flight blkif requests get completed, since they probably contain bits of the guest's memory image and that's not going to get saved any other way. Hence, re-issuing of in-flight requests as in case of xen resume will not work here. This is in contrast to xen-suspend where we need to freeze with as little processing as possible to avoid dirtying RAM late in the migration cycle and we know that in-flight data can wait. Add freeze, thaw and restore callbacks for PM suspend and hibernation support. All frontend drivers that needs to use PM_HIBERNATION/PM_SUSPEND events, need to implement these xenbus_driver callbacks. The freeze handler stops block-layer queue and disconnect the frontend from the backend while freeing ring_info and associated resources. Before disconnecting from the backend, we need to prevent any new IO from being queued and wait for existing IO to complete. Freeze/unfreeze of the queues will guarantee that there are no requests in use on the shared ring. However, for sanity we should check state of the ring before disconnecting to make sure that there are no outstanding requests to be processed on the ring. The restore handler re-allocates ring_info, unquiesces and unfreezes the queue and re-connect to the backend, so that rest of the kernel can continue to use the block device transparently. Note:For older backends,if a backend doesn't have commit'12ea729645ace' xen/blkback: unmap all persistent grants when frontend gets disconnected, the frontend may see massive amount of grant table warning when freeing resources. [ 36.852659] deferring g.e. 0xf9 (pfn 0xffffffffffffffff) [ 36.855089] xen:grant_table: WARNING:e.g. 0x112 still in use! In this case, persistent grants would need to be disabled. [Anchal Agarwal: Changelog]: RFC v1->v2: Removed timeout per request before disconnect during blkfront freeze. Added queue freeze/quiesce to the blkfront_freeze Code cleanup RFC v2->v3: None RFC v3->v1: Code cleanup, Refractoring v1->v2: * remove err variable in blkfront_freeze * BugFix: error handling if rings are still busy after queue freeze/quiesce and returnign driver to connected state * add TODO if blkback fails to disconnect on freeze * Code formatting Signed-off-by: Anchal Agarwal Signed-off-by: Munehisa Kamata --- drivers/block/xen-blkfront.c | 122 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 118 insertions(+), 4 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 3bb3dd8da9b0..500f1753e339 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -48,6 +48,8 @@ #include #include #include +#include +#include #include #include @@ -80,6 +82,8 @@ enum blkif_state { BLKIF_STATE_DISCONNECTED, BLKIF_STATE_CONNECTED, BLKIF_STATE_SUSPENDED, + BLKIF_STATE_FREEZING, + BLKIF_STATE_FROZEN, }; struct grant { @@ -219,6 +223,7 @@ struct blkfront_info struct list_head requests; struct bio_list bio_list; struct list_head info_list; + struct completion wait_backend_disconnected; }; static unsigned int nr_minors; @@ -1005,6 +1010,7 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size, info->sector_size = sector_size; info->physical_sector_size = physical_sector_size; blkif_set_queue_limits(info); + init_completion(&info->wait_backend_disconnected); return 0; } @@ -1353,6 +1359,8 @@ static void blkif_free(struct blkfront_info *info, int suspend) unsigned int i; struct blkfront_ring_info *rinfo; + if (info->connected == BLKIF_STATE_FREEZING) + goto free_rings; /* Prevent new requests being issued until we fix things up. */ info->connected = suspend ? BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED; @@ -1360,6 +1368,7 @@ static void blkif_free(struct blkfront_info *info, int suspend) if (info->rq) blk_mq_stop_hw_queues(info->rq); +free_rings: for_each_rinfo(info, rinfo, i) blkif_free_ring(rinfo); @@ -1563,8 +1572,10 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id) struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)dev_id; struct blkfront_info *info = rinfo->dev_info; - if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) + if (unlikely(info->connected != BLKIF_STATE_CONNECTED && + info->connected != BLKIF_STATE_FREEZING)) { return IRQ_HANDLED; + } spin_lock_irqsave(&rinfo->ring_lock, flags); again: @@ -2027,6 +2038,7 @@ static int blkif_recover(struct blkfront_info *info) struct bio *bio; unsigned int segs; struct blkfront_ring_info *rinfo; + bool frozen = info->connected == BLKIF_STATE_FROZEN; blkfront_gather_backend_features(info); /* Reset limits changed by blk_mq_update_nr_hw_queues(). */ @@ -2049,6 +2061,9 @@ static int blkif_recover(struct blkfront_info *info) kick_pending_request_queues(rinfo); } + if (frozen) + return 0; + list_for_each_entry_safe(req, n, &info->requests, queuelist) { /* Requeue pending requests (flush or discard) */ list_del_init(&req->queuelist); @@ -2365,6 +2380,7 @@ static void blkfront_connect(struct blkfront_info *info) return; case BLKIF_STATE_SUSPENDED: + case BLKIF_STATE_FROZEN: /* * If we are recovering from suspension, we need to wait * for the backend to announce it's features before @@ -2482,12 +2498,37 @@ static void blkback_changed(struct xenbus_device *dev, break; case XenbusStateClosed: - if (dev->state == XenbusStateClosed) + if (dev->state == XenbusStateClosed) { + if (info->connected == BLKIF_STATE_FREEZING) { + blkif_free(info, 0); + info->connected = BLKIF_STATE_FROZEN; + complete(&info->wait_backend_disconnected); + } break; + } + /* + * We receive backend's Closed again while thawing + * or restoring and it causes thawing or restoring to fail. + * During blkfront_restore, backend is still in Closed state + * and we receive backend as closed here while frontend's + * dev->state is set to XenBusStateInitialized. + * Ignore such unexpected state regardless of the backend's + * state. + */ + if (info->connected == BLKIF_STATE_FROZEN) { + dev_dbg(&dev->dev, "Thawing/Restoring, ignore the backend's Closed state: %s", + dev->nodename); + break; + } + /* fall through */ case XenbusStateClosing: - if (info) - blkfront_closing(info); + if (info) { + if (info->connected == BLKIF_STATE_FREEZING) + xenbus_frontend_closed(dev); + else + blkfront_closing(info); + } break; } } @@ -2631,6 +2672,76 @@ static void blkif_release(struct gendisk *disk, fmode_t mode) mutex_unlock(&blkfront_mutex); } +static int blkfront_freeze(struct xenbus_device *dev) +{ + unsigned int i; + struct blkfront_info *info = dev_get_drvdata(&dev->dev); + struct blkfront_ring_info *rinfo; + /* This would be reasonable timeout as used in xenbus_dev_shutdown() */ + unsigned int timeout = 5 * HZ; + unsigned long flags; + + info->connected = BLKIF_STATE_FREEZING; + + blk_mq_freeze_queue(info->rq); + blk_mq_quiesce_queue(info->rq); + + for_each_rinfo(info, rinfo, i) { + /* No more gnttab callback work. */ + gnttab_cancel_free_callback(&rinfo->callback); + /* Flush gnttab callback work. Must be done with no locks held. */ + flush_work(&rinfo->work); + } + + for_each_rinfo(info, rinfo, i) { + spin_lock_irqsave(&rinfo->ring_lock, flags); + if (RING_FULL(&rinfo->ring) || + RING_HAS_UNCONSUMED_RESPONSES(&rinfo->ring)) { + spin_unlock_irqrestore(&rinfo->ring_lock, flags); + xenbus_dev_error(dev, -EBUSY, "Hibernation Failed. The ring is still busy"); + info->connected = BLKIF_STATE_CONNECTED; + blk_mq_unquiesce_queue(info->rq); + blk_mq_unfreeze_queue(info->rq); + return -EBUSY; + } + spin_unlock_irqrestore(&rinfo->ring_lock, flags); + } + /* Kick the backend to disconnect */ + xenbus_switch_state(dev, XenbusStateClosing); + + /* + * We don't want to move forward before the frontend is diconnected + * from the backend cleanly. + * TODO:Handle timeout by falling back to the normal + * disconnect path and just wait for the backend to close before + * reconnecting. Bring the system back to its original state by + * failing hibernation gracefully. + */ + timeout = wait_for_completion_timeout(&info->wait_backend_disconnected, + timeout); + if (!timeout) { + xenbus_dev_error(dev, -EBUSY, "Freezing timed out;" + "the device may become inconsistent state"); + return -EBUSY; + } + + return 0; +} + +static int blkfront_restore(struct xenbus_device *dev) +{ + struct blkfront_info *info = dev_get_drvdata(&dev->dev); + int err; + + err = talk_to_blkback(dev, info); + if (!err) { + blk_mq_update_nr_hw_queues(&info->tag_set, info->nr_rings); + blk_mq_unquiesce_queue(info->rq); + blk_mq_unfreeze_queue(info->rq); + } + return err; +} + static const struct block_device_operations xlvbd_block_fops = { .owner = THIS_MODULE, @@ -2654,6 +2765,9 @@ static struct xenbus_driver blkfront_driver = { .resume = blkfront_resume, .otherend_changed = blkback_changed, .is_ready = blkfront_is_ready, + .freeze = blkfront_freeze, + .thaw = blkfront_restore, + .restore = blkfront_restore, }; static void purge_persistent_grants(struct blkfront_info *info) From patchwork Fri Aug 21 22:29:55 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anchal Agarwal X-Patchwork-Id: 256979 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=-11.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 79CDBC433E1 for ; Fri, 21 Aug 2020 22:30:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 518CC20738 for ; Fri, 21 Aug 2020 22:30:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="Y0GwpSGF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726773AbgHUWaU (ORCPT ); Fri, 21 Aug 2020 18:30:20 -0400 Received: from smtp-fw-4101.amazon.com ([72.21.198.25]:30896 "EHLO smtp-fw-4101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726747AbgHUWaU (ORCPT ); Fri, 21 Aug 2020 18:30:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1598049020; x=1629585020; h=date:from:to:subject:message-id:references:mime-version: in-reply-to; bh=YPGbk1ro99+2byQqY7wPsPaRaSmgzuUay7e4tUoB1AM=; b=Y0GwpSGFmXYdsWq+z4vz6YIJHIaIMEhXEyPR1F38J/jYNhI4dwoK55gM gzqqBGmRkvB3cn/X6nne40JI30uYbFIBgiA0iL7Xhq8vk08mnsCHMyIaK nYQMptdlbsflRcsvfsF8yX5yskkowFXllvR96x9X8S1sTI7lyC32Bsl/9 w=; X-IronPort-AV: E=Sophos;i="5.76,338,1592870400"; d="scan'208";a="49403800" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-1d-5dd976cd.us-east-1.amazon.com) ([10.43.8.6]) by smtp-border-fw-out-4101.iad4.amazon.com with ESMTP; 21 Aug 2020 22:30:19 +0000 Received: from EX13MTAUWC001.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan2.iad.amazon.com [10.40.159.162]) by email-inbound-relay-1d-5dd976cd.us-east-1.amazon.com (Postfix) with ESMTPS id 06E32A2486; Fri, 21 Aug 2020 22:30:11 +0000 (UTC) Received: from EX13D05UWC003.ant.amazon.com (10.43.162.226) by EX13MTAUWC001.ant.amazon.com (10.43.162.135) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 21 Aug 2020 22:29:55 +0000 Received: from EX13MTAUWC001.ant.amazon.com (10.43.162.135) by EX13D05UWC003.ant.amazon.com (10.43.162.226) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 21 Aug 2020 22:29:55 +0000 Received: from dev-dsk-anchalag-2a-9c2d1d96.us-west-2.amazon.com (172.22.96.68) by mail-relay.amazon.com (10.43.162.232) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Fri, 21 Aug 2020 22:29:54 +0000 Received: by dev-dsk-anchalag-2a-9c2d1d96.us-west-2.amazon.com (Postfix, from userid 4335130) id 3480C40362; Fri, 21 Aug 2020 22:29:55 +0000 (UTC) Date: Fri, 21 Aug 2020 22:29:55 +0000 From: Anchal Agarwal To: , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v3 08/11] x86/xen: save and restore steal clock during PM hibernation Message-ID: <5c3be5c7519b1f63a51b08abc388c33bd6f66661.1598042152.git.anchalag@amazon.com> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Save/restore steal times in syscore suspend/resume during PM hibernation. Commit '5e25f5db6abb9: ("xen/time: do not decrease steal time after live migration on xen")' fixes xen guest steal time handling during migration. A similar issue is seen during PM hibernation. Currently, steal time accounting code in scheduler expects steal clock callback to provide monotonically increasing value. If the accounting code receives a smaller value than previous one, it uses a negative value to calculate steal time and results in incorrectly updated idle and steal time accounting. This breaks userspace tools which read /proc/stat. top - 08:05:35 up 2:12, 3 users, load average: 0.00, 0.07, 0.23 Tasks: 80 total, 1 running, 79 sleeping, 0 stopped, 0 zombie Cpu(s): 0.0%us, 0.0%sy, 0.0%ni,30100.0%id, 0.0%wa, 0.0%hi, 0.0%si,-1253874204672.0%st This can actually happen when a Xen PVHVM guest gets restored from hibernation, because such a restored guest is just a fresh domain from Xen perspective and the time information in runstate info starts over from scratch. Changelog: v1->v2: Removed patches that introduced new function calls for saving/restoring sched clock offset and using existing ones that are used during LM Signed-off-by: Anchal Agarwal --- arch/x86/xen/suspend.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c index 550aa0fc9465..b12db6966af6 100644 --- a/arch/x86/xen/suspend.c +++ b/arch/x86/xen/suspend.c @@ -99,6 +99,7 @@ static int xen_syscore_suspend(void) gnttab_suspend(); + xen_manage_runstate_time(-1); xrfp.domid = DOMID_SELF; xrfp.gpfn = __pa(HYPERVISOR_shared_info) >> PAGE_SHIFT; @@ -119,7 +120,7 @@ static void xen_syscore_resume(void) xen_hvm_map_shared_info(); pvclock_resume(); - + xen_manage_runstate_time(0); gnttab_resume(); } 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: 256978 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=-11.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 A7A70C433DF for ; Fri, 21 Aug 2020 22:31:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 81A9D207DF for ; Fri, 21 Aug 2020 22:31:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="RgsIr8Z7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727830AbgHUWa7 (ORCPT ); Fri, 21 Aug 2020 18:30:59 -0400 Received: from smtp-fw-4101.amazon.com ([72.21.198.25]:12254 "EHLO smtp-fw-4101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726747AbgHUWa5 (ORCPT ); Fri, 21 Aug 2020 18:30:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1598049057; x=1629585057; h=date:from:to:subject:message-id:references:mime-version: in-reply-to; bh=8mKR6nGsN4/J6yUPoHqgy6Vb/KbDSfcnRfNiku5bjZI=; b=RgsIr8Z7VXg/2KiGmru6OI2t0IpbT+jjoTnyR+KBB1255FwjNnNT5zSG LTwZRsFZd5c/zrYvE/mDlVNPKXZsu119muuZfuZ0zZOpcR5B/cwpZMYHF IQ7GrE3nZUGkSB8JSkg3PWKM5pbiZMUhjnGB8Qv6N6pS5UvmHuhmuELLe E=; 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) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org 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(); }