From patchwork Tue Jul 19 17:02:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Dr. David Alan Gilbert" X-Patchwork-Id: 12922838 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 7C4F0C433EF for ; Tue, 19 Jul 2022 17:47:51 +0000 (UTC) Received: from localhost ([::1]:36366 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oDrK2-000358-HH for qemu-devel@archiver.kernel.org; Tue, 19 Jul 2022 13:47:50 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43032) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oDqck-0006tD-3S for qemu-devel@nongnu.org; Tue, 19 Jul 2022 13:03:07 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:44455) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oDqci-0002z0-4T for qemu-devel@nongnu.org; Tue, 19 Jul 2022 13:03:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1658250183; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4zcK+6dry+L1L47kPTO8uIkf+ST9oXTYo4lRfB4nReU=; b=dQ6vgBIbGBJrmAc+wj0asfHLv4E3LvNQO2cJ+SHxMJZL/WDT54Kgc4lDvueVoHyL4YlWsm DzmjSmkBwXKqCkwEy8IfGCcphpdp002i4qrTtscck0GLjP4EIlah0GdA4/TdSsvyVKcEdP tZL632hGhDmIUluXRpd4hnguaJgXoBE= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-300-wR8MjRR-NnmBuhSmRJCQow-1; Tue, 19 Jul 2022 13:02:59 -0400 X-MC-Unique: wR8MjRR-NnmBuhSmRJCQow-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id ED29C3C1014A; Tue, 19 Jul 2022 17:02:58 +0000 (UTC) Received: from dgilbert-t580.localhost (unknown [10.33.36.162]) by smtp.corp.redhat.com (Postfix) with ESMTP id 04C0840CFD0A; Tue, 19 Jul 2022 17:02:57 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, leobras@redhat.com, quintela@redhat.com, berrange@redhat.com, peterx@redhat.com, iii@linux.ibm.com, huangy81@chinatelecom.cn Subject: [PULL 27/29] migration/multifd: Report to user when zerocopy not working Date: Tue, 19 Jul 2022 18:02:19 +0100 Message-Id: <20220719170221.576190-28-dgilbert@redhat.com> In-Reply-To: <20220719170221.576190-1-dgilbert@redhat.com> References: <20220719170221.576190-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 Received-SPF: pass client-ip=170.10.133.124; envelope-from=dgilbert@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=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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" From: Leonardo Bras Some errors, like the lack of Scatter-Gather support by the network interface(NETIF_F_SG) may cause sendmsg(...,MSG_ZEROCOPY) to fail on using zero-copy, which causes it to fall back to the default copying mechanism. After each full dirty-bitmap scan there should be a zero-copy flush happening, which checks for errors each of the previous calls to sendmsg(...,MSG_ZEROCOPY). If all of them failed to use zero-copy, then increment dirty_sync_missed_zero_copy migration stat to let the user know about it. Signed-off-by: Leonardo Bras Reviewed-by: Daniel P. Berrangé Acked-by: Peter Xu Message-Id: <20220711211112.18951-4-leobras@redhat.com> Signed-off-by: Dr. David Alan Gilbert --- migration/multifd.c | 2 ++ migration/ram.c | 5 +++++ migration/ram.h | 2 ++ 3 files changed, 9 insertions(+) diff --git a/migration/multifd.c b/migration/multifd.c index 1e49594b02..586ddc9d65 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -624,6 +624,8 @@ int multifd_send_sync_main(QEMUFile *f) if (ret < 0) { error_report_err(err); return -1; + } else if (ret == 1) { + dirty_sync_missed_zero_copy(); } } } diff --git a/migration/ram.c b/migration/ram.c index 4fbad74c6c..b94669ba5d 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -434,6 +434,11 @@ static void ram_transferred_add(uint64_t bytes) ram_counters.transferred += bytes; } +void dirty_sync_missed_zero_copy(void) +{ + ram_counters.dirty_sync_missed_zero_copy++; +} + /* used by the search for pages to send */ struct PageSearchStatus { /* Current block being searched */ diff --git a/migration/ram.h b/migration/ram.h index 5d90945a6e..c7af65ac74 100644 --- a/migration/ram.h +++ b/migration/ram.h @@ -89,4 +89,6 @@ void ram_write_tracking_prepare(void); int ram_write_tracking_start(void); void ram_write_tracking_stop(void); +void dirty_sync_missed_zero_copy(void); + #endif