From patchwork Fri Oct 2 17:53:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 303795 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=-12.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 757B6C4363C for ; Fri, 2 Oct 2020 17:56:33 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 D6DA1206DD for ; Fri, 2 Oct 2020 17:56:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ReOcH29y" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D6DA1206DD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:47460 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kOPIF-00047O-Qn for qemu-devel@archiver.kernel.org; Fri, 02 Oct 2020 13:56:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48368) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kOPGp-0002Mz-5z for qemu-devel@nongnu.org; Fri, 02 Oct 2020 13:55:04 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:55206) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kOPGl-0005El-SQ for qemu-devel@nongnu.org; Fri, 02 Oct 2020 13:55:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1601661299; h=from:from: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=Vx+Hot1wSXytFGZn9Y3x89aH6Pp0nwmA/pTo/g6zg/M=; b=ReOcH29ysagrJrLRROC7huBbWaeZTmIKPqe3Hjs3xOz+rCIOuTHkz2pYet1+IvyGsQjo5V /pVucsOg6N8HmboCgDvj3ZpsHybx7hAYBNmrCBc6+M4n3U8758pWPBSgTnP51krTyNyZqI YfebhWzpCmi9YMKTP4MY8bWsAa9gOOg= Received: from mail-qt1-f197.google.com (mail-qt1-f197.google.com [209.85.160.197]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-217-LwwSpMGHMv60mEQA7wJP6g-1; Fri, 02 Oct 2020 13:53:44 -0400 X-MC-Unique: LwwSpMGHMv60mEQA7wJP6g-1 Received: by mail-qt1-f197.google.com with SMTP id 60so1550892qtf.21 for ; Fri, 02 Oct 2020 10:53:44 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Vx+Hot1wSXytFGZn9Y3x89aH6Pp0nwmA/pTo/g6zg/M=; b=UVVKnFBjonFilePhTBCJ8bpNfEQswJcdOeKrKSpBERpss36av2UiYZXebwyMGhUZQ8 SOggbUnph4jsIXmm2sErq0KT7GpCOAMG/6dg9zipnT7fDd2/SNX8uaaBw5XFFQNY1Z7y 2N1BSwTbCYnYuuPeaEqbMJP5XVTWq1GCs7wCo2ZUysLJLZToP09fCsbZGKZ2EKGcVIw/ TE4yfrK7P5njBTHS5nhlWdn2SNsrpk2mRIjxWuLtGyJ6+5MQWwjTtEhhxh8G2KBsNdAb n7Xj/v384CB/ER/uH19yD14f0ZVFpLv2iKRqDLx1t46v7Ku/nyfnojqGAVs0tixkAGTe Uo0g== X-Gm-Message-State: AOAM530242Jrapbek7eMUTlSDfQoyqwYSX5zHT3NCcIXeJpaPcOYm9ZW UdgerKBXTWTj/kAxoczNVZccbRO7vYVTJvkzda+9z0BJRG9BMBvvGOttRr2RcKDTdCprhjeu/Nk oF6jjcq15SrLZfVo= X-Received: by 2002:ad4:52e3:: with SMTP id p3mr3072689qvu.42.1601661224157; Fri, 02 Oct 2020 10:53:44 -0700 (PDT) X-Google-Smtp-Source: ABdhPJy68Blgtf9zKN5k5AKJUK220BH4aZWwCjaOC0kiM0FUXYTB/HW8Sop5hbRsjmYWw16udz49wg== X-Received: by 2002:ad4:52e3:: with SMTP id p3mr3072670qvu.42.1601661223911; Fri, 02 Oct 2020 10:53:43 -0700 (PDT) Received: from xz-x1.redhat.com (toroon474qw-lp130-09-184-147-14-204.dsl.bell.ca. [184.147.14.204]) by smtp.gmail.com with ESMTPSA id a3sm1562229qtp.63.2020.10.02.10.53.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Oct 2020 10:53:43 -0700 (PDT) From: Peter Xu To: qemu-devel@nongnu.org Subject: [PATCH v4 4/4] migration: Sync requested pages after postcopy recovery Date: Fri, 2 Oct 2020 13:53:36 -0400 Message-Id: <20201002175336.30858-5-peterx@redhat.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201002175336.30858-1-peterx@redhat.com> References: <20201002175336.30858-1-peterx@redhat.com> MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=peterx@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=216.205.24.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/02 01:13:31 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Xiaohui Li , "Dr . David Alan Gilbert" , peterx@redhat.com, Juan Quintela Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" We synchronize the requested pages right after a postcopy recovery happens. This helps to synchronize the prioritized pages on source so that the faulted threads can be served faster. Reported-by: Xiaohui Li Signed-off-by: Peter Xu Reviewed-by: Dr. David Alan Gilbert --- migration/savevm.c | 57 ++++++++++++++++++++++++++++++++++++++++++ migration/trace-events | 1 + 2 files changed, 58 insertions(+) diff --git a/migration/savevm.c b/migration/savevm.c index 34e4b71052..1dc021ee53 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -2011,6 +2011,49 @@ static int loadvm_postcopy_handle_run(MigrationIncomingState *mis) return LOADVM_QUIT; } +/* We must be with page_request_mutex held */ +static gboolean postcopy_sync_page_req(gpointer key, gpointer value, + gpointer data) +{ + MigrationIncomingState *mis = data; + void *host_addr = (void *) key; + ram_addr_t rb_offset; + RAMBlock *rb; + int ret; + + rb = qemu_ram_block_from_host(host_addr, true, &rb_offset); + if (!rb) { + /* + * This should _never_ happen. However be nice for a migrating VM to + * not crash/assert. Post an error (note: intended to not use *_once + * because we do want to see all the illegal addresses; and this can + * never be triggered by the guest so we're safe) and move on next. + */ + error_report("%s: illegal host addr %p", __func__, host_addr); + /* Try the next entry */ + return FALSE; + } + + ret = migrate_send_rp_message_req_pages(mis, rb, rb_offset); + if (ret) { + /* Please refer to above comment. */ + error_report("%s: send rp message failed for addr %p", + __func__, host_addr); + return FALSE; + } + + trace_postcopy_page_req_sync(host_addr); + + return FALSE; +} + +static void migrate_send_rp_req_pages_pending(MigrationIncomingState *mis) +{ + WITH_QEMU_LOCK_GUARD(&mis->page_request_mutex) { + g_tree_foreach(mis->page_requested, postcopy_sync_page_req, mis); + } +} + static int loadvm_postcopy_handle_resume(MigrationIncomingState *mis) { if (mis->state != MIGRATION_STATUS_POSTCOPY_RECOVER) { @@ -2033,6 +2076,20 @@ static int loadvm_postcopy_handle_resume(MigrationIncomingState *mis) /* Tell source that "we are ready" */ migrate_send_rp_resume_ack(mis, MIGRATION_RESUME_ACK_VALUE); + /* + * After a postcopy recovery, the source should have lost the postcopy + * queue, or potentially the requested pages could have been lost during + * the network down phase. Let's re-sync with the source VM by re-sending + * all the pending pages that we eagerly need, so these threads won't get + * blocked too long due to the recovery. + * + * Without this procedure, the faulted destination VM threads (waiting for + * page requests right before the postcopy is interrupted) can keep hanging + * until the pages are sent by the source during the background copying of + * pages, or another thread faulted on the same address accidentally. + */ + migrate_send_rp_req_pages_pending(mis); + return 0; } diff --git a/migration/trace-events b/migration/trace-events index e4d5eb94ca..0fbfd2da60 100644 --- a/migration/trace-events +++ b/migration/trace-events @@ -49,6 +49,7 @@ vmstate_save(const char *idstr, const char *vmsd_name) "%s, %s" vmstate_load(const char *idstr, const char *vmsd_name) "%s, %s" postcopy_pause_incoming(void) "" postcopy_pause_incoming_continued(void) "" +postcopy_page_req_sync(void *host_addr) "sync page req %p" # vmstate.c vmstate_load_field_error(const char *field, int ret) "field \"%s\" load failed, ret = %d"