From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EAB472505A5; Mon, 3 Nov 2025 07:18:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762154299; cv=none; b=szGrH+LcCOZHuv90q+rft+bxmJEz9HQPoz4X7fKOuM2fTs+jowEtghZ9niM0lsW2zKQzcmFZ3uHSbHd79nFCarPElKSfuxWUDPt6G4fhqxAoXWjprnvnc4tqt0FeIn1BDU6+aDZdOs/n8tBTyCSz/2vrKMRvvSOlrHhk+ysYSrs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762154299; c=relaxed/simple; bh=vlAqAmTDh4Z/QVBO24ytbjpGSmt0U77g+FzG3aQu5i4=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=GVuq8zjUzJwLV6xsPsZ1RqgITd4O1NzYG+TqfRAKmkXmCCaWgYMC51iX+bGcnKWuSHBXLhpFlcqPTdPvQxzHfM113DP6rTy7it3bCL643TsG9gAbB+DHGpc9kqMp/qwNRV6jchVxe9KZjwfNwMoQGYT0yhYavlWod2GKUpyhYjA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sXgqXUKr; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="sXgqXUKr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E082C116B1; Mon, 3 Nov 2025 07:18:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762154298; bh=vlAqAmTDh4Z/QVBO24ytbjpGSmt0U77g+FzG3aQu5i4=; h=Date:Subject:To:References:From:In-Reply-To:From; b=sXgqXUKrx4uv7eCDDbOTW1FX2EPok9okwx0Lrr6XBQ45+D708jWbU21sZDvabs/hn qvNvsMevjEkOo6P3J42RSOQ3Ac+pQ5EdatTBhtEwIUWGGrBBq20xe3q6xxFFsJNKul /8fHCp3TUL/EkkGaTHHAsONSBNYkj8+xxoX+y49HwtFgaCqvyAbc+/FfzYtRjHwDSZ gAuXGCMs1NkkiH83gyEO+vnrejyB8h3zyAACvbXKd1oLdL+P7gTfjX8PJox2wBwNln TWVE+b2XT2lo4y1t4cK//cuvil16uW/0WrZZAuJVZhSMMX8d6tnb/t/8nekeQqT4jb GMfwQhjssGKGQ== Message-ID: <7a8d31de-f1bb-468f-8a44-2787f0080dcf@kernel.org> Date: Mon, 3 Nov 2025 16:18:14 +0900 Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 09/13] block: introduce blkdev_report_zones_cached() To: Bart Van Assche , Jens Axboe , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, Keith Busch , Christoph Hellwig , dm-devel@lists.linux.dev, Mike Snitzer , Mikulas Patocka , "Martin K . Petersen" , linux-scsi@vger.kernel.org, linux-xfs@vger.kernel.org, Carlos Maiolino , linux-btrfs@vger.kernel.org, David Sterba References: <20251031061307.185513-1-dlemoal@kernel.org> <20251031061307.185513-10-dlemoal@kernel.org> <4287484a-3a3d-4f50-9c5b-7a901458bfbc@acm.org> Content-Language: en-US From: Damien Le Moal Organization: Western Digital Research In-Reply-To: <4287484a-3a3d-4f50-9c5b-7a901458bfbc@acm.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/1/25 06:53, Bart Van Assche wrote: > On 10/30/25 11:13 PM, Damien Le Moal wrote: >> Introduce the function blkdev_report_zones_cached() to provide a fast >> report zone built using the blkdev_get_zone_info() function, which gets >> zone information from a disk zones_cond array or zone write plugs. >> For a large capacity SMR drive, such fast report zone can be completed >> in a few millioseconds compared to several seconds completion times >> when the report zone is obtained from the device. > > millioseconds -> milliseconds > > Does retrieving the cached zone information really require multiple > milliseconds instead of only a few microseconds? There are over 100,000 zones on large capacity SMR HDDs. And I have models with smaller zone size that have over 200,000 zones. So yes, a few milliseconds are needed on normal (read not super fast) CPUs. -- Damien Le Moal Western Digital Research