From patchwork Tue Jun 20 13:03:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13285816 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 B4146EB64D7 for ; Tue, 20 Jun 2023 13:05:36 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qBb24-0002jF-B9; Tue, 20 Jun 2023 09:04:28 -0400 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 1qBb21-0002iW-Nn for qemu-devel@nongnu.org; Tue, 20 Jun 2023 09:04:26 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qBb20-0006tl-9R for qemu-devel@nongnu.org; Tue, 20 Jun 2023 09:04:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1687266263; 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=9gikf4BE2vltak5Ude6T1zo0pu9yDG/S+fZmZfG7HRA=; b=ZCp0BLqKr78Ua7//vIHIIO1HPAttlpmbtTXzWHMoE8dwEcYVxdv64Z9O90YfE3vhFMjb5z ZOMkqEdApk0/gwZNecMHud8MgASxJTrvJFHVG0Ol76EgftTpxkoKBsv8qiKX0dmURAF2I+ jFJhI3e7reoRZfhp5UDwFJUkBzZMtNo= 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-278-z3Djug2QPWW3k3QjP9XUpA-1; Tue, 20 Jun 2023 09:04:21 -0400 X-MC-Unique: z3Djug2QPWW3k3QjP9XUpA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2C9B23C0F67B; Tue, 20 Jun 2023 13:04:02 +0000 (UTC) Received: from t480s.fritz.box (unknown [10.39.193.26]) by smtp.corp.redhat.com (Postfix) with ESMTP id 506622166B26; Tue, 20 Jun 2023 13:04:00 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Cc: David Hildenbrand , "Michael S. Tsirkin" , Juan Quintela , Peter Xu , Leonardo Bras , Paolo Bonzini , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Peng Tao Subject: [PATCH v1 2/4] virtio-mem: Skip most of virtio_mem_unplug_all() without plugged memory Date: Tue, 20 Jun 2023 15:03:52 +0200 Message-Id: <20230620130354.322180-3-david@redhat.com> In-Reply-To: <20230620130354.322180-1-david@redhat.com> References: <20230620130354.322180-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Received-SPF: pass client-ip=170.10.133.124; envelope-from=david@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_H5=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 Already when starting QEMU we perform one system reset that ends up triggering virtio_mem_unplug_all() with no actual memory plugged yet. That, in turn will trigger ram_block_discard_range() and perform some other actions that are not required in that case. Let's optimize virtio_mem_unplug_all() for the case that no memory is plugged. This will be beneficial for x-ignore-shared support as well. Signed-off-by: David Hildenbrand --- hw/virtio/virtio-mem.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c index 538b695c29..9f6169af32 100644 --- a/hw/virtio/virtio-mem.c +++ b/hw/virtio/virtio-mem.c @@ -606,20 +606,20 @@ static int virtio_mem_unplug_all(VirtIOMEM *vmem) { RAMBlock *rb = vmem->memdev->mr.ram_block; - if (virtio_mem_is_busy()) { - return -EBUSY; - } - - if (ram_block_discard_range(rb, 0, qemu_ram_get_used_length(rb))) { - return -EBUSY; - } - virtio_mem_notify_unplug_all(vmem); - - bitmap_clear(vmem->bitmap, 0, vmem->bitmap_size); if (vmem->size) { + if (virtio_mem_is_busy()) { + return -EBUSY; + } + if (ram_block_discard_range(rb, 0, qemu_ram_get_used_length(rb))) { + return -EBUSY; + } + virtio_mem_notify_unplug_all(vmem); + + bitmap_clear(vmem->bitmap, 0, vmem->bitmap_size); vmem->size = 0; notifier_list_notify(&vmem->size_change_notifiers, &vmem->size); } + trace_virtio_mem_unplugged_all(); virtio_mem_resize_usable_region(vmem, vmem->requested_size, true); return 0;