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 715C3C46CD8 for ; Fri, 22 Dec 2023 10:38:46 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rGcv6-0000EP-95; Fri, 22 Dec 2023 05:38:20 -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 1rGcv4-0000EC-GS for qemu-devel@nongnu.org; Fri, 22 Dec 2023 05:38:18 -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 1rGcv2-0002yL-Pu for qemu-devel@nongnu.org; Fri, 22 Dec 2023 05:38:18 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1703241495; 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: in-reply-to:in-reply-to:references:references; bh=o0BSyKkgp4Ck20HWn4xpEfLbAblV38ipvHBs2yMK1ss=; b=GTYFHhAxbp1NmNARURLKZipRDqSLAoAzRRvPC1toMjH+GvYtcLx6EvpvGu2G8jCAcwrdTN wt51wEvCNv3ZBkHcpQgNuA7Zfxm+CwNf1+xoEC0D1pf7P8vQ2pZYIb0fGB66D8h0Wlwu1R Scy2SAJ5jTRe51AsxSLU4ldHJ0Ro/0Y= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-265-JeS3pqRrM8aa6HUjW_Zb3A-1; Fri, 22 Dec 2023 05:38:12 -0500 X-MC-Unique: JeS3pqRrM8aa6HUjW_Zb3A-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D43433C02750; Fri, 22 Dec 2023 10:38:11 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.129]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B39F9492BFA; Fri, 22 Dec 2023 10:38:11 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id AE2A821E6920; Fri, 22 Dec 2023 11:38:10 +0100 (CET) From: Markus Armbruster To: Fabiano Rosas Cc: qemu-devel@nongnu.org, berrange@redhat.com, Juan Quintela , Peter Xu , Leonardo Bras , Claudio Fontana , Eric Blake Subject: Re: [RFC PATCH v3 23/30] migration: Add direct-io parameter In-Reply-To: <20231127202612.23012-24-farosas@suse.de> (Fabiano Rosas's message of "Mon, 27 Nov 2023 17:26:05 -0300") References: <20231127202612.23012-1-farosas@suse.de> <20231127202612.23012-24-farosas@suse.de> Date: Fri, 22 Dec 2023 11:38:10 +0100 Message-ID: <87v88qttd9.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.10 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.061, 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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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 Fabiano Rosas writes: > Add the direct-io migration parameter that tells the migration code to > use O_DIRECT when opening the migration stream file whenever possible. Why is that useful? > This is currently only used with fixed-ram migration for the multifd > channels that transfer the RAM pages. Those channels only transfer the > pages and are guaranteed to perform aligned writes. > > However the parameter could be made to affect other types of > file-based migrations in the future. > > Signed-off-by: Fabiano Rosas [...] > diff --git a/qapi/migration.json b/qapi/migration.json > index 3b93e13743..1d38619842 100644 > --- a/qapi/migration.json > +++ b/qapi/migration.json > @@ -878,6 +878,9 @@ > # @mode: Migration mode. See description in @MigMode. Default is 'normal'. > # (Since 8.2) > # > +# @direct-io: Open migration files with O_DIRECT when possible. This > +# requires that the 'fixed-ram' capability is enabled. (since 9.0) Two spaces between sentences for consistency, please. > +# > # Features: > # > # @deprecated: Member @block-incremental is deprecated. Use > @@ -911,7 +914,8 @@ > 'block-bitmap-mapping', > { 'name': 'x-vcpu-dirty-limit-period', 'features': ['unstable'] }, > 'vcpu-dirty-limit', > - 'mode'] } > + 'mode', > + 'direct-io'] } > > ## > # @MigrateSetParameters: > @@ -1066,6 +1070,9 @@ > # @mode: Migration mode. See description in @MigMode. Default is 'normal'. > # (Since 8.2) > # > +# @direct-io: Open migration files with O_DIRECT when possible. This > +# requires that the 'fixed-ram' capability is enabled. (since 9.0) > +# > # Features: > # > # @deprecated: Member @block-incremental is deprecated. Use > @@ -1119,7 +1126,8 @@ > '*x-vcpu-dirty-limit-period': { 'type': 'uint64', > 'features': [ 'unstable' ] }, > '*vcpu-dirty-limit': 'uint64', > - '*mode': 'MigMode'} } > + '*mode': 'MigMode', > + '*direct-io': 'bool' } } > > ## > # @migrate-set-parameters: > @@ -1294,6 +1302,9 @@ > # @mode: Migration mode. See description in @MigMode. Default is 'normal'. > # (Since 8.2) > # > +# @direct-io: Open migration files with O_DIRECT when possible. This > +# requires that the 'fixed-ram' capability is enabled. (since 9.0) > +# > # Features: > # > # @deprecated: Member @block-incremental is deprecated. Use > @@ -1344,7 +1355,8 @@ > '*x-vcpu-dirty-limit-period': { 'type': 'uint64', > 'features': [ 'unstable' ] }, > '*vcpu-dirty-limit': 'uint64', > - '*mode': 'MigMode'} } > + '*mode': 'MigMode', > + '*direct-io': 'bool' } } > > ## > # @query-migrate-parameters: [...]