From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-io1-f54.google.com (mail-io1-f54.google.com [209.85.166.54]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5197691 for ; Tue, 12 Dec 2023 09:42:27 -0800 (PST) Received: by mail-io1-f54.google.com with SMTP id ca18e2360f4ac-7b6fa79b547so351115139f.1 for ; Tue, 12 Dec 2023 09:42:27 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702402946; x=1703007746; 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=q+gS8FgjYGOJzlLiWHZHMdMu5WYv6GcbSYGpOAsbDgQ=; b=IQnRWyCZTAsYeVUvsQprqxS9RLVx3UKF6TqrmsP6HPwYcPW1GKK51c3S78EJO9RXoZ kn22VBMtLflS7aiUdf/5sbSbLUSXUywn47is3DdqzPXChRY0tHfHOKI0Z+r6oCFNN0SQ DZZTVTu70PbX2S69Jv/HxuNpR30ahRGj2+hwZyG13WPeDrKsu9ZQqSNo6iM5UZgJi9NG 0uty/wrCUQTLVDfLNY/PYy9qAxrWBqtBbkq686WHLA9+0P4ynwWuWi+BlMiEA3J/jrzn jOiVd+SzIWYIbBWKMLyTkIL+0EpkmBmkvzJq9jdG4ni9Y1YocbYK+GPu0pj7c2zJEzX6 EKOg== X-Gm-Message-State: AOJu0YxFAVDomRAaN6Dp1XQdONpBvXG8GRYX0m1DRdKTHTT3EtRXPmUF wHSN8gxd0IOMxff10VBqKDNYqyvmRmw= X-Google-Smtp-Source: AGHT+IEUyoS/7vmpF0Hb4UQcmc0fZm2hx7IOpI48M2beeRDp/xLAOeezXLNEmtWWS0kjCVWOv/5m5Q== X-Received: by 2002:a05:6e02:178a:b0:35d:6caf:78c4 with SMTP id y10-20020a056e02178a00b0035d6caf78c4mr9562243ilu.80.1702402946452; Tue, 12 Dec 2023 09:42:26 -0800 (PST) Received: from ?IPV6:2620:0:1000:8411:4cb1:76fa:137e:ca8? ([2620:0:1000:8411:4cb1:76fa:137e:ca8]) by smtp.gmail.com with ESMTPSA id b32-20020a630c20000000b0059d34fb9ccasm8397938pgl.2.2023.12.12.09.42.25 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 12 Dec 2023 09:42:26 -0800 (PST) Message-ID: <686cc853-96e2-4aa4-8f68-fdcc5cdabbba@acm.org> Date: Tue, 12 Dec 2023 09:42:24 -0800 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 3/3] block/mq-deadline: Disable I/O prioritization in certain cases Content-Language: en-US To: Christoph Hellwig Cc: Damien Le Moal , Jens Axboe , linux-block@vger.kernel.org, Jaegeuk Kim References: <20231205053213.522772-1-bvanassche@acm.org> <20231205053213.522772-4-bvanassche@acm.org> <20231211165720.GC26039@lst.de> <177773fd-c8ed-4822-9344-3058e820ddf0@kernel.org> <20231212154140.GB20933@lst.de> <42054848-2e8d-4856-b404-c042a4365097@acm.org> <20231212171846.GA28682@lst.de> From: Bart Van Assche In-Reply-To: <20231212171846.GA28682@lst.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 12/12/23 09:18, Christoph Hellwig wrote: > On Tue, Dec 12, 2023 at 09:15:48AM -0800, Bart Van Assche wrote: >> As mentioned before, UFS devices implement the SCSI command set and hence do not >> support write append operations. If anyone else standardizes a write append >> command for SCSI we can ask UFS vendors to implement that command. However, as >> far as I know nobody in T10 is working on standardizing a write append command. > > The actual hardware support does not matter, it's the programming model. > Even with the zone append emulation in sd you don't need to care about > reordering due to I/O priorities. The actual hardware support does matter. Using the zone append emulation from drivers/scsi/sd_zbc.c (or any other zone append emulation) is not an option for high performance devices. This is because emulating zone append can only be done by serializing write operations. Any such serialization negatively affects performance. Thanks, Bart.