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 X-Spam-Level: X-Spam-Status: No, score=-5.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2EA73C433E3 for ; Tue, 7 Jul 2020 15:31:23 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id ED4DA204EC for ; Tue, 7 Jul 2020 15:31:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="doJz8bgc" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ED4DA204EC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:47736 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jspZ4-00050T-9H for qemu-devel@archiver.kernel.org; Tue, 07 Jul 2020 11:31:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49926) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jspYD-0004S3-8v for qemu-devel@nongnu.org; Tue, 07 Jul 2020 11:30:29 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:56822 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jspYB-0007qR-I4 for qemu-devel@nongnu.org; Tue, 07 Jul 2020 11:30:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1594135826; 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=7uhudkcqYa+dJJQVsnYss9EKCCASOYmltouF21ej5Pc=; b=doJz8bgcKwGoDW2xZX6n7TpovOptItdd5rOEkFnncev1Xziw8YqW5kdnQIviEk8mhdEM1v NCLbF5oN+Q/KUTyeYM4FV1X7DcGENofssZzeff3GitagbP1yy7loRb9mnFy56stYATXp5X TJIFtRCC6XkQ3zfg05wseuOwP/8SJF0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-301-7lOhl7LDNj6XwzMasPwVsA-1; Tue, 07 Jul 2020 11:30:06 -0400 X-MC-Unique: 7lOhl7LDNj6XwzMasPwVsA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3E0F01052509; Tue, 7 Jul 2020 15:30:05 +0000 (UTC) Received: from [10.3.113.97] (ovpn-113-97.phx2.redhat.com [10.3.113.97]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2511973FE0; Tue, 7 Jul 2020 15:30:04 +0000 (UTC) Subject: Re: [PATCH] qemu-img map: Don't limit block status request size To: Kevin Wolf References: <20200707144629.51235-1-kwolf@redhat.com> <9f74d8dc-9c4e-d519-9dd7-0895ece3de17@redhat.com> <20200707152147.GC7002@linux.fritz.box> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <8cfe5adb-a2ae-86cd-51af-4ba25c34336d@redhat.com> Date: Tue, 7 Jul 2020 10:30:03 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20200707152147.GC7002@linux.fritz.box> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eblake@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=207.211.31.81; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/07 00:20:54 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, 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_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, qemu-devel@nongnu.org, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 7/7/20 10:21 AM, Kevin Wolf wrote: > Am 07.07.2020 um 16:54 hat Eric Blake geschrieben: >> On 7/7/20 9:46 AM, Kevin Wolf wrote: >>> Limiting each loop iteration of qemu-img map to 1 GB was arbitrary from >>> the beginning, though it only cut the maximum in half then because the >>> interface a signed 32 bit byte count. These days, bdrv_block_status() interface was a >>> supports a 64 bit byte count, so the arbitrary limit is even worse. >>> >>> On file-posix, bdrv_block_status() eventually maps to SEEK_HOLE and >>> SEEK_DATA, which don't support a limit, but always do all of the work >>> necessary to find the start of the next hole/data. Much of this work may >>> be repeated if we don't use this information fully, but query with an >>> only slightly larger offset in the next loop iteration. Therefore, if >>> bdrv_block_status() is called in a loop, it should always pass the >>> full number of bytes that the whole loop is interested in. >>> >>> This removes the arbitrary limit and speeds up 'qemu-img map' >>> significantly on heavily fragmented images. >>> >>> Signed-off-by: Kevin Wolf >>> --- >>> qemu-img.c | 5 +---- >>> 1 file changed, 1 insertion(+), 4 deletions(-) >> >> Do you want this in 5.1? It seems like a nice optimization. > > I guess now that I have your R-b, I can sneak both patches in for soft > freeze. :-) Can we treat optimizations for speed problems as bug fixes if they land after soft freeze but before -rc1? At any rate, this post reminds me that Vladimir's series to support 64-bit actions elsewhere has probably slipped into 5.2 territory, but I still need to fix the fact that nbd is sending uint32_t trim/zero values into signed int block layer functions (Vladimir's work is nicer but harder to review, so I'll probably end up writing one-off patches for 5.1 with minimal churn to just block/nbd.c rather than the whole block layer...) -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org