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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1053EE784AB for ; Mon, 2 Oct 2023 17:03:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238599AbjJBRDF (ORCPT ); Mon, 2 Oct 2023 13:03:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57176 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238594AbjJBRDE (ORCPT ); Mon, 2 Oct 2023 13:03:04 -0400 Received: from mail-pf1-f175.google.com (mail-pf1-f175.google.com [209.85.210.175]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60EC5BF; Mon, 2 Oct 2023 10:03:02 -0700 (PDT) Received: by mail-pf1-f175.google.com with SMTP id d2e1a72fcca58-69101022969so14987130b3a.3; Mon, 02 Oct 2023 10:03:02 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1696266182; x=1696870982; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=5rgW1P/kbPRRjPU2p9ZFV6J7W8Gynjv0+wqv7Y18r3U=; b=qpdHFZsecS7UTg5FAy2rJ+jycK0xTrBeBav0i4i0tNzNW7CzlCCEbHx0DHPRx9Ck4r Gzd67VZjbbXtUAybMjNhXP7PDny4PBmjlw1Vptk7Z6slBhcJXcKc9ROMDsr1J0waCcPS XEFi333SCNEL+3uJKh/bPGmNpPwGPEKgGE6CdIj8Lsg0u4oLro6PJzIF6U448CaTZFAF Ig0s63Q5dy7Ij/6JInhWGla7Pb+88mLtBzw1r/xLNkEe6r9jykQ18RGNuxoOiDi6HDVO I8/INThqEzHIdaqOkQvG5/R1Nv69deEXP3uqTYWg+HkJUm0C86RSKRfxZtX4vmIZQUGy mhGw== X-Gm-Message-State: AOJu0Yy4sYrn51YFpMeJAbjkMWkQ0aBNxzJQ854FpWmwi/HZAED0zeVz 2/kA/V5ogXoPrUmSRT80AVb06rh7kzo= X-Google-Smtp-Source: AGHT+IGyYr19Sl3Lhb6nq16oygKsbBzpUV8uwf2c0t5ClepWOQiK6E2Pj5bDYZYKyWtiFZA+hMZsqw== X-Received: by 2002:a05:6a00:24c8:b0:692:a727:1fdd with SMTP id d8-20020a056a0024c800b00692a7271fddmr15279022pfv.4.1696266181593; Mon, 02 Oct 2023 10:03:01 -0700 (PDT) Received: from ?IPV6:2620:15c:211:201:6ad7:f663:5f97:db57? ([2620:15c:211:201:6ad7:f663:5f97:db57]) by smtp.gmail.com with ESMTPSA id u19-20020aa78493000000b006933e71956dsm8786432pfn.9.2023.10.02.10.03.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 02 Oct 2023 10:03:01 -0700 (PDT) Message-ID: <3780fa8e-bdad-40b3-853d-e24fe25e8a94@acm.org> Date: Mon, 2 Oct 2023 10:02:59 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 04/13] block: Restore write hint support Content-Language: en-US To: Avri Altman , Jens Axboe Cc: "linux-block@vger.kernel.org" , "linux-scsi@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "Martin K . Petersen" , Christoph Hellwig , Alexander Viro , Christian Brauner , Jaegeuk Kim , Chao Yu , "Darrick J. Wong" References: <20230920191442.3701673-1-bvanassche@acm.org> <20230920191442.3701673-5-bvanassche@acm.org> From: Bart Van Assche In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 10/2/23 04:23, Avri Altman wrote: >> The following aspects of that commit have been dropped: >> - Debugfs support for retrieving and modifying write hints. > > Any particular reason to left those out? The above comment is misleading: what has not been restored is the struct request_queue write_hints[] array member nor the debugfs interface for accessing that array. My understanding is that that array was used to track stream statistics by the NVMe driver. From version v5.17 of the NVMe driver: if (streamid < ARRAY_SIZE(req->q->write_hints)) req->q->write_hints[streamid] += blk_rq_bytes(req) >> 9; >> - md-raid, BTRFS, ext4, gfs2 and zonefs write hint support. > > Native Linux with ext4 is being used in automotive, and even mobile > platforms. E.g. Qualcomm's RB5 is formally maintained with Debian - > https://releases.linaro.org/96boards/rb5/linaro/debian/21.12/ All ext4 did with write hint information is to copy the inode write hint information into the bio. The inode write hint information is set by the F_SET_RW_HINT fcntl. The only software packages that use the F_SET_RW_HINT fcntl and that I'm aware of are RocksDB, Samba, stress_ng and rr. Are any of these software packages used in automotive software on top of ext4? Thanks, Bart.