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 6CB24E936E8 for ; Wed, 4 Oct 2023 21:01:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233900AbjJDVBF (ORCPT ); Wed, 4 Oct 2023 17:01:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40034 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233577AbjJDVBE (ORCPT ); Wed, 4 Oct 2023 17:01:04 -0400 Received: from mail-pf1-f173.google.com (mail-pf1-f173.google.com [209.85.210.173]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8BAD89E; Wed, 4 Oct 2023 14:01:01 -0700 (PDT) Received: by mail-pf1-f173.google.com with SMTP id d2e1a72fcca58-69101d33315so204680b3a.3; Wed, 04 Oct 2023 14:01:01 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1696453261; x=1697058061; 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=MqWCjpGoPtGeBxPj6NXaJjfTI+0jdvkGwu/+8Rx4Pz4=; b=LCtAqZbXV5EEBnFNAca0GPoeTLEa2hsqHrwR7Pls/FiUK7wc98ledPW4TKRH0pXfqH uT8SIsiC2ayCfIGuiDpPeOtnoh/bVV6ig6sryt17Mrzyc9w6T+EKGQFAkSkIeyXKbmSP RyxJM/kArK9xkwaZwjGwLym7OfguHOsGRMPDBhTpKtrZuQyU2U22kbO5KFQNaE7dA9HB gOwS8YEK8/9/XD50PMCB86wqvtyBRLNZ1iT0mGNF4do0QPqGLqkmkEFTlI9VZkrCV6qS D7SgUM9srYhxtWYfXDOIg+lG3y/rKt2Gk3JqJ3rJCDr/ZAJOdZW0E3UKSLsQMxKvibv4 HIfg== X-Gm-Message-State: AOJu0YxiLL41GZnvhwRwoh7lUo0woL0sDiAaOgWg1HdQV2S6PRkoCI/O zzs61cbnOApW1NQbPUlT3rM= X-Google-Smtp-Source: AGHT+IEuGjzH8Kj7y4GInNBPROGHOmz2jLurje3529a8epyygBEeFbbe5C5V5No2qUQIED/PIYh8gA== X-Received: by 2002:a05:6a00:b84:b0:68f:ccea:8e14 with SMTP id g4-20020a056a000b8400b0068fccea8e14mr4137143pfj.32.1696453260897; Wed, 04 Oct 2023 14:01:00 -0700 (PDT) Received: from ?IPV6:2620:15c:211:201:969d:167a:787c:a6c7? ([2620:15c:211:201:969d:167a:787c:a6c7]) by smtp.gmail.com with ESMTPSA id a24-20020aa78658000000b006934e7ceb79sm3657241pfo.32.2023.10.04.14.00.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 04 Oct 2023 14:01:00 -0700 (PDT) Message-ID: <45bc1c01-09c7-4c54-b305-f349d0d0e19b@acm.org> Date: Wed, 4 Oct 2023 14:00:58 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 01/21] block: Add atomic write operations to request_queue limits Content-Language: en-US To: "Martin K. Petersen" Cc: John Garry , axboe@kernel.dk, kbusch@kernel.org, hch@lst.de, sagi@grimberg.me, jejb@linux.ibm.com, djwong@kernel.org, viro@zeniv.linux.org.uk, brauner@kernel.org, chandan.babu@oracle.com, dchinner@redhat.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, tytso@mit.edu, jbongio@google.com, linux-api@vger.kernel.org, Himanshu Madhani References: <20230929102726.2985188-1-john.g.garry@oracle.com> <20230929102726.2985188-2-john.g.garry@oracle.com> <7f031c7a-1830-4331-86f9-4d5fbca94b8a@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 10/3/23 20:00, Martin K. Petersen wrote: > > Bart, > >> also that there are no guarantees that the data written by an atomic >> write will survive a power failure. See also the difference between >> the NVMe parameters AWUN and AWUPF. > > We only care about *PF. The *N variants were cut from the same cloth as > TRIM and UNMAP. Hi Martin, Has the following approach been considered? RWF_ATOMIC only guarantees atomicity. Persistence is not guaranteed without fsync() / fdatasync(). I think this would be more friendly towards battery-powered devices (smartphones). On these devices it can be safe to skip fsync() / fdatasync() if the battery level is high enough. Thanks, Bart.