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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 98550C433FE for ; Mon, 21 Nov 2022 13:00:44 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ox6P9-0001tw-JW; Mon, 21 Nov 2022 08:00:07 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ox6P8-0001si-8r for qemu-devel@nongnu.org; Mon, 21 Nov 2022 08:00:06 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ox6P5-0006XW-Bb for qemu-devel@nongnu.org; Mon, 21 Nov 2022 08:00:05 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1669035602; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=o0zwjIEQ0RGHrg3uupRJrCxkZxGKrVGbvF+zRHI8YNI=; b=MsO7w6q5Kux9llAAh02tIZC0LWVOfe/q52+3HZDvUSyMmuShWTHtNHZrp8Rm2Hhn0iDzSv tq1V3YnrUFxl8C5S54a3xIMIY+SDjPXZwRFqxRAn+Emg1XP5wiG+LUt3Ghm6/vzPV2040V MNtS2JcZyMl71X36gWLps18B4DUqYb0= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-70-Ez6osqvMOOWF37znrdMTig-1; Mon, 21 Nov 2022 07:59:28 -0500 X-MC-Unique: Ez6osqvMOOWF37znrdMTig-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C0EA0801585; Mon, 21 Nov 2022 12:59:27 +0000 (UTC) Received: from secure.mitica (unknown [10.39.193.227]) by smtp.corp.redhat.com (Postfix) with ESMTP id 18A8FC15BB3; Mon, 21 Nov 2022 12:59:25 +0000 (UTC) From: Juan Quintela To: qemu-devel@nongnu.org Cc: Stefan Hajnoczi , "Dr. David Alan Gilbert" , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Fam Zheng , Juan Quintela , qemu-block@nongnu.org, David Hildenbrand , Peter Xu , Paolo Bonzini Subject: [PULL 7/8] migration: Disable multifd explicitly with compression Date: Mon, 21 Nov 2022 13:59:06 +0100 Message-Id: <20221121125907.62469-8-quintela@redhat.com> In-Reply-To: <20221121125907.62469-1-quintela@redhat.com> References: <20221121125907.62469-1-quintela@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 Received-SPF: pass client-ip=170.10.129.124; envelope-from=quintela@redhat.com; helo=us-smtp-delivery-124.mimecast.com 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_H2=-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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Peter Xu Multifd thread model does not work for compression, explicitly disable it. Note that previuosly even we can enable both of them, nothing will go wrong, because the compression code has higher priority so multifd feature will just be ignored. Now we'll fail even earlier at config time so the user should be aware of the consequence better. Note that there can be a slight chance of breaking existing users, but let's assume they're not majority and not serious users, or they should have found that multifd is not working already. With that, we can safely drop the check in ram_save_target_page() for using multifd, because when multifd=on then compression=off, then the removed check on save_page_use_compression() will also always return false too. Signed-off-by: Peter Xu Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela --- migration/migration.c | 7 +++++++ migration/ram.c | 11 +++++------ 2 files changed, 12 insertions(+), 6 deletions(-) diff --git a/migration/migration.c b/migration/migration.c index f3ed77a7d0..f485eea5fb 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -1350,6 +1350,13 @@ static bool migrate_caps_check(bool *cap_list, } } + if (cap_list[MIGRATION_CAPABILITY_MULTIFD]) { + if (cap_list[MIGRATION_CAPABILITY_COMPRESS]) { + error_setg(errp, "Multifd is not compatible with compress"); + return false; + } + } + return true; } diff --git a/migration/ram.c b/migration/ram.c index 1d42414ecc..1338e47665 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -2305,13 +2305,12 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss) } /* - * Do not use multifd for: - * 1. Compression as the first page in the new block should be posted out - * before sending the compressed page - * 2. In postcopy as one whole host page should be placed + * Do not use multifd in postcopy as one whole host page should be + * placed. Meanwhile postcopy requires atomic update of pages, so even + * if host page size == guest page size the dest guest during run may + * still see partially copied pages which is data corruption. */ - if (!save_page_use_compression(rs) && migrate_use_multifd() - && !migration_in_postcopy()) { + if (migrate_use_multifd() && !migration_in_postcopy()) { return ram_save_multifd_page(rs, block, offset); } -- 2.38.1