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[99.241.198.116]) by smtp.gmail.com with ESMTPSA id f15-20020a056e020b4f00b002d125725709sm59575ilu.28.2022.05.17.12.57.33 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Tue, 17 May 2022 12:57:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1652817458; 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=WlxP3mzG79FvL1utUjQMn5yT8ZTiCbWippa7BQ3pxe4=; b=EWqr4VRI7wMT3D8j3Ifsa/XjsAfR+44jzNqYhwpIMZN9OHdnY33PGrHV430BXWWmg+4yWK Ex37jeC/kP5MC/C1waFV+LsyN0p/6Yrj34oRqLfTgbX95fyNEFA+Z3trd0vsSBp197bt3x 8TsB28gLhahgxl98v27B/1FaNWLeCLk= X-MC-Unique: 3gfJwBKXP3qAXPvoGlCzLg-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=WlxP3mzG79FvL1utUjQMn5yT8ZTiCbWippa7BQ3pxe4=; b=ZM3z59olM9l2qzxP8rTgJOWQcRCbtJKCSj6yduxSSRN41jG9mdv/wCQ04LmD2LR0ab P96eKS4wSn0QjVYfBy2z4M5Xrjuxd9H1qtJD0X34rhqSliMJaTS7emSUTAYbxYH7Bbrb j778ahcg/PpIkFYC3E592jlClfM8+lcG/lLnU7BhLO2MbKRquCHIkp4+qauQR8eLGbzx iWLzuGbZ4vjaQ4PhCUF1spsIFtzDtVLBjDoEDI/3BO6dQRxXDCbAeGpDpoLgk0if1e/B GOzUHsk/Voqoi1K+obAC4eL79Vq4SmVt/I/6zqiTT0h7Mn5N6LbzhFk9FDUt51e3l1G/ 23MA== X-Gm-Message-State: AOAM533yBB2O1o13KpJ9Svwa4eznY+MxxyWQi0YFi3DGUh37QOtya0cW saTbzJ+ukotzddXan8KtscimnVzNSY3sPgaM41cXG2AQVpvLRYY8ptv96xNXDTkaffwkryTGXDF wT8JAcAja1CkCFqh+NM6SedqVGe1vCfsr1nu6Ejzg/0L4p2uQloLvzO79ZaAabmyp X-Received: by 2002:a05:6602:2f06:b0:65d:fd3a:96cc with SMTP id q6-20020a0566022f0600b0065dfd3a96ccmr6648220iow.14.1652817455622; Tue, 17 May 2022 12:57:35 -0700 (PDT) X-Google-Smtp-Source: ABdhPJw5QM36zwwB+/6r+n3OWSabhtTuHfKw00MGfjAE++WeYv7refELCibMzFelj5uBr2o1LxSctw== X-Received: by 2002:a05:6602:2f06:b0:65d:fd3a:96cc with SMTP id q6-20020a0566022f0600b0065dfd3a96ccmr6648207iow.14.1652817455293; Tue, 17 May 2022 12:57:35 -0700 (PDT) From: Peter Xu To: qemu-devel@nongnu.org Cc: peterx@redhat.com, Leonardo Bras Soares Passos , Juan Quintela , Manish Mishra , "Dr . David Alan Gilbert" , "Daniel P . Berrange" Subject: [PATCH v6 01/13] migration: Add postcopy-preempt capability Date: Tue, 17 May 2022 15:57:18 -0400 Message-Id: <20220517195730.32312-2-peterx@redhat.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220517195730.32312-1-peterx@redhat.com> References: <20220517195730.32312-1-peterx@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1652817588984100001 Content-Type: text/plain; charset="utf-8" Firstly, postcopy already preempts precopy due to the fact that we do unqueue_page() first before looking into dirty bits. However that's not enough, e.g., when there're host huge page enabled, when sending a precopy huge page, a postcopy request needs to wait until the who= le huge page that is sending to finish. That could introduce quite some delay, the bigger the huge page is the larger delay it'll bring. This patch adds a new capability to allow postcopy requests to preempt exis= ting precopy page during sending a huge page, so that postcopy requests can be serviced even faster. Meanwhile to send it even faster, bypass the precopy stream by providing a standalone postcopy socket for sending requested pages. Since the new behavior will not be compatible with the old behavior, this w= ill not be the default, it's enabled only when the new capability is set on both src/dst QEMUs. This patch only adds the capability itself, the logic will be added in foll= ow up patches. Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Peter Xu --- migration/migration.c | 23 +++++++++++++++++++++++ migration/migration.h | 1 + qapi/migration.json | 8 +++++++- 3 files changed, 31 insertions(+), 1 deletion(-) diff --git a/migration/migration.c b/migration/migration.c index 31739b2af9..f15e1593ac 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -1240,6 +1240,11 @@ static bool migrate_caps_check(bool *cap_list, error_setg(errp, "Postcopy is not compatible with ignore-share= d"); return false; } + + if (cap_list[MIGRATION_CAPABILITY_MULTIFD]) { + error_setg(errp, "Multifd is not supported in postcopy"); + return false; + } } =20 if (cap_list[MIGRATION_CAPABILITY_BACKGROUND_SNAPSHOT]) { @@ -1283,6 +1288,13 @@ static bool migrate_caps_check(bool *cap_list, return false; } =20 + if (cap_list[MIGRATION_CAPABILITY_POSTCOPY_PREEMPT]) { + if (!cap_list[MIGRATION_CAPABILITY_POSTCOPY_RAM]) { + error_setg(errp, "Postcopy preempt requires postcopy-ram"); + return false; + } + } + return true; } =20 @@ -2669,6 +2681,15 @@ bool migrate_background_snapshot(void) return s->enabled_capabilities[MIGRATION_CAPABILITY_BACKGROUND_SNAPSHO= T]; } =20 +bool migrate_postcopy_preempt(void) +{ + MigrationState *s; + + s =3D migrate_get_current(); + + return s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_PREEMPT]; +} + /* migration thread support */ /* * Something bad happened to the RP stream, mark an error @@ -4283,6 +4304,8 @@ static Property migration_properties[] =3D { DEFINE_PROP_MIG_CAP("x-compress", MIGRATION_CAPABILITY_COMPRESS), DEFINE_PROP_MIG_CAP("x-events", MIGRATION_CAPABILITY_EVENTS), DEFINE_PROP_MIG_CAP("x-postcopy-ram", MIGRATION_CAPABILITY_POSTCOPY_RA= M), + DEFINE_PROP_MIG_CAP("x-postcopy-preempt", + MIGRATION_CAPABILITY_POSTCOPY_PREEMPT), DEFINE_PROP_MIG_CAP("x-colo", MIGRATION_CAPABILITY_X_COLO), DEFINE_PROP_MIG_CAP("x-release-ram", MIGRATION_CAPABILITY_RELEASE_RAM), DEFINE_PROP_MIG_CAP("x-block", MIGRATION_CAPABILITY_BLOCK), diff --git a/migration/migration.h b/migration/migration.h index 485d58b95f..d2269c826c 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -400,6 +400,7 @@ int migrate_decompress_threads(void); bool migrate_use_events(void); bool migrate_postcopy_blocktime(void); bool migrate_background_snapshot(void); +bool migrate_postcopy_preempt(void); =20 /* Sending on the return path - generic and then for each message type */ void migrate_send_rp_shut(MigrationIncomingState *mis, diff --git a/qapi/migration.json b/qapi/migration.json index 6130cd9fae..d8c3810ba2 100644 --- a/qapi/migration.json +++ b/qapi/migration.json @@ -461,6 +461,12 @@ # procedure starts. The VM RAM is saved with running= VM. # (since 6.0) # +# @postcopy-preempt: If enabled, the migration process will allow postcopy +# requests to preempt precopy stream, so postcopy reque= sts +# will be handled faster. This is a performance featur= e and +# should not affect the correctness of postcopy migrati= on. +# (since 7.1) +# # Features: # @unstable: Members @x-colo and @x-ignore-shared are experimental. # @@ -474,7 +480,7 @@ 'block', 'return-path', 'pause-before-switchover', 'multifd', 'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate', { 'name': 'x-ignore-shared', 'features': [ 'unstable' ] }, - 'validate-uuid', 'background-snapshot'] } + 'validate-uuid', 'background-snapshot', 'postcopy-preempt'] } =20 ## # @MigrationCapabilityStatus: --=20 2.32.0