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To: John Garry , Keith Busch Cc: Christoph Hellwig , Alan Adamson , "Martin K. Petersen" , Jens Axboe , linux-nvme@lists.infradead.org, linux-block@vger.kernel.org References: <20250707141834.GA30198@lst.de> <27a01d31-0432-4340-9f45-1595f66f0500@linux.ibm.com> Content-Language: en-US From: Nilay Shroff In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=EJELElZC c=1 sm=1 tr=0 ts=68f7a086 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=I5r0CxplrSDLCy34:21 a=IkcTkHD0fZMA:10 a=x6icFKpwvdMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=yPCof4ZbAAAA:8 a=TakWwMvn3hYBPWLwZwUA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMDE4MDAyMiBTYWx0ZWRfX9kyN3yeIF1VP lFJJrlwUuBVhHNK3FogKnywjZqb3LY/SqgUeMZY0/GgT5hsULn2RVI8gcCUOSvEG3xhWKbRoh3B K8U1Yt/qSuiZhj8rOEJTnZMJfb5qZhzg/V/1nu9BRf/XsZhoXuiTTKmK9+UL/j82Y5AfwiDLmGV NXEKCcPmzxoY3H5ug/5yj8vlV+//ihBAt/9xxdHBNxCpPREdZA60JkhlkL57cRFLNkhNi6yVgaN 1oRYgcIUdNf7YoZx1xFSVjdLQwodkslZAq7NkoIF3ytW8NN7IzPGwMS8X8gRQzeMLAG5hpJOBLN hlQSH0v1Qy7CCriubiqEqzFFJq6NIHZOEvyU9zkgA2IHg+Lx1IHHp4hTS3E5Vi36W/v1YGaSOT6 iXAW1S5uqKurxre3Pgrcawa2ZK+J5g== X-Proofpoint-GUID: xIWKchR_gvnhykSQPwUL9AvJTejebeoA X-Proofpoint-ORIG-GUID: xIWKchR_gvnhykSQPwUL9AvJTejebeoA X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-10-21_02,2025-10-13_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 priorityscore=1501 suspectscore=0 bulkscore=0 spamscore=0 malwarescore=0 phishscore=0 adultscore=0 lowpriorityscore=0 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510020000 definitions=main-2510180022 On 10/20/25 7:12 PM, John Garry wrote: > On 10/07/2025 06:07, Nilay Shroff wrote: >>> Considering multi-controller subsystems, some controllers might have >>> namespaces with only 512b formats attached, and other controllers might >>> have some 4k mixed in, so then they can't all consistently report the >>> desired AWUPF value. They'd have to just scale AWUPF based on the >>> largest sector size supported. Which I guess is what the current wording >>> is guiding toward, but that just suggests host drivers disregard the >>> value and use NAWUPF instead. So still option III. >> Yes, I agree — option III seems to be the best possible way forward. >> However, does this mean we would disregard atomic write support for any >> multi-controller NVMe vendor that consistently reports a valid AWUPF value >> across all controllers and namespace formats, but sets NAWUPF to zero? > > Hi Nilay, > > Does the drive which you are using report NAWUPF as zero (as hinted)? > > If so, have you tried the following https://lore.kernel.org/linux-nvme/20250820150220.1923826-1-john.g.garry@oracle.com/ > > We were considering changing the NVMe driver to not use AWUPF at all... Yes, I just tested your patch with the latest upstream kernel on my drive, which reports a non-zero AWUPF but a zero NAWUPF. And your opt-in change works well on my disk. So we may consider merging this change if everyone agrees. Thanks, --Nilay