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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY autolearn=no 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 BDB34C17440 for ; Wed, 13 Nov 2019 01:48:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9444D222CA for ; Wed, 13 Nov 2019 01:48:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="ixDJXdjz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727020AbfKMBsg (ORCPT ); Tue, 12 Nov 2019 20:48:36 -0500 Received: from userp2120.oracle.com ([156.151.31.85]:49028 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726958AbfKMBsg (ORCPT ); Tue, 12 Nov 2019 20:48:36 -0500 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xAD1jUxi010736; Wed, 13 Nov 2019 01:48:13 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=to : cc : subject : from : references : date : in-reply-to : message-id : mime-version : content-type; s=corp-2019-08-05; bh=3YrFERbsr0dX0JOQWz/1uKzLQS6DAn/XlnRevr39op0=; b=ixDJXdjzvKV7mWJdrgXv+tqaBIgjLvGjT2AuuY/uWMeuPyNBYXWZ0NpHLD+7UElXHYE6 1j38dPKL0ge5dzPCaQHo+wYfjpIqtCy3RqnY1CYMce9Rkq62UVH/bPDxQC8xR+N9AT7K sGY9sbV9L51N8+beWW/PhAEVth3hS1hlcsJxHBVZ3eTgNgzY104nFFL1cFBT4A3yaiea 5rAFN2iwMryr5TPo4cQsf8AKq35A9ACRzGuRrDPsFUiMAi2WxoS1NrQmzykAinymF1TX 6sYX7BGSezWtnaTArDZOOpAWy39mGlij63npGDjXgxa+GnO4sdC1WlZBJs34Hcf2RYp3 7g== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by userp2120.oracle.com with ESMTP id 2w5p3qrqu5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 13 Nov 2019 01:48:12 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xAD1cJue070559; Wed, 13 Nov 2019 01:46:12 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3020.oracle.com with ESMTP id 2w7j046fan-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 13 Nov 2019 01:46:12 +0000 Received: from abhmp0018.oracle.com (abhmp0018.oracle.com [141.146.116.24]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id xAD1k9Vu012008; Wed, 13 Nov 2019 01:46:09 GMT Received: from ca-mkp.ca.oracle.com (/10.159.214.123) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 12 Nov 2019 17:46:09 -0800 To: Damien Le Moal Cc: linux-block@vger.kernel.org, Jens Axboe , linux-scsi@vger.kernel.org, "Martin K . Petersen" , dm-devel@redhat.com, Mike Snitzer , linux-f2fs-devel@lists.sourceforge.net, Jaegeuk Kim , Chao Yu Subject: Re: [PATCH v2 8/9] scsi: sd_zbc: Cleanup sd_zbc_alloc_report_buffer() From: "Martin K. Petersen" Organization: Oracle Corporation References: <20191111023930.638129-1-damien.lemoal@wdc.com> <20191111023930.638129-9-damien.lemoal@wdc.com> Date: Tue, 12 Nov 2019 20:46:06 -0500 In-Reply-To: <20191111023930.638129-9-damien.lemoal@wdc.com> (Damien Le Moal's message of "Mon, 11 Nov 2019 11:39:29 +0900") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1.92 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9439 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=932 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1910280000 definitions=main-1911130009 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9439 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=998 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1910280000 definitions=main-1911130010 Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Damien, > There is no need to arbitrarily limit the size of a report zone to the > number of zones defined by SD_ZBC_REPORT_MAX_ZONES. Rather, simply > calculate the report buffer size needed for the requested number of > zones without exceeding the device total number of zones. This buffer > size limitation to the hardware maximum transfer size and page mapping > capabilities is kept unchanged. Starting with this initial buffer size, > the allocation is optimized by iterating over decreasing buffer size > until the allocation succeeds (each iteration is allowed to fail fast > using the __GFP_NORETRY flag). This ensures forward progress for zone > reports and avoids failures of zones revalidation under memory pressure. Acked-by: Martin K. Petersen -- Martin K. Petersen Oracle Linux Engineering