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Thu, 1 May 2025 10:28:26 +0000 (GMT) Message-ID: <06aa7604-bf57-421c-8906-bc4162e665cd@linux.ibm.com> Date: Thu, 1 May 2025 15:58:25 +0530 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 V4 15/24] block: unifying elevator change To: Ming Lei , Jens Axboe , linux-block@vger.kernel.org Cc: Shinichiro Kawasaki , =?UTF-8?Q?Thomas_Hellstr=C3=B6m?= , Christoph Hellwig , Hannes Reinecke References: <20250430043529.1950194-1-ming.lei@redhat.com> <20250430043529.1950194-16-ming.lei@redhat.com> Content-Language: en-US From: Nilay Shroff In-Reply-To: <20250430043529.1950194-16-ming.lei@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNTAxMDA3NyBTYWx0ZWRfXzyCBsaA7zCAA FXhDtmXS0dfbgWFyA09A7yrzbS00QWSQIBRBgYv5lG6AMAJtOUB+bgHURD71CqOu8ox07varbyF RdgIk4prxjh94YgIDPEMrVvl8vXJePUWpe5cYKbUVMOnH3K/xcbi8rwIyKluniV4C6/QpTL/E2Z uXdBec3a47/GzLImAQjvVOzqUM32ZTO+MnJjTzYEDnh0DmXNylyr522aM6r2vkSUPs1Q0sbxvSj 7ZQ67i/2w0cJjYMr6Rg4RfQbPAiyK1nfgSGOzRkE/4w/d5BhgWBESWoencCU0VDGlxb2BBoUMYV 8B0bk3YyRnDLv0YiZlGpvNVlWZe+bCC2go3BD/qzXty6Tgpoq+upVb+m3ofbeH0ZbWLsXnvE9TV Vsg0tNw4iUT7nZCwAqeGilIPOQ45AnVp/7JKcG937PVZeHTbFoxlw5hwokgXtnhbdFtS1pIG X-Authority-Analysis: v=2.4 cv=GI8IEvNK c=1 sm=1 tr=0 ts=68134ccf cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=IkcTkHD0fZMA:10 a=dt9VzEwgFbYA:10 a=20KFwNOVAAAA:8 a=VnNF1IyMAAAA:8 a=RyKiTIznjPsxi7qa8aUA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: GnGjNbvotHjEmLIFR9Sy5_U8ZCJlwmZo X-Proofpoint-ORIG-GUID: GnGjNbvotHjEmLIFR9Sy5_U8ZCJlwmZo X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.0.736,FMLib:17.12.80.40 definitions=2025-05-01_03,2025-04-24_02,2025-02-21_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 spamscore=0 mlxlogscore=999 mlxscore=0 bulkscore=0 clxscore=1015 priorityscore=1501 lowpriorityscore=0 malwarescore=0 suspectscore=0 adultscore=0 impostorscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2504070000 definitions=main-2505010077 On 4/30/25 10:05 AM, Ming Lei wrote: > Elevator change is one well-define behavior: > > - tear down current elevator if it exists > > - setup new elevator > > It is supposed to cover any case for changing elevator by single > internal API, typically the following cases: > > - setup default elevator in add_disk() > > - switch to none in del_disk() > > - reset elevator in blk_mq_update_nr_hw_queues() > > - switch elevator in sysfs `store` elevator attribute > > This patch uses elevator_change() to cover all above cases: > > - every elevator switch is serialized with each other: add_disk/del_disk/ > store elevator is serialized already, blk_mq_update_nr_hw_queues() uses > srcu for syncing with the other three cases > > - for both add_disk()/del_disk(), queue freeze works at atomic mode > or has been froze, so the freeze in elevator_change() won't add extra > delay > > - `struct elev_change_ctx` instance holds any info for changing elevator > > Reviewed-by: Hannes Reinecke > Signed-off-by: Ming Lei Looks good to me: Reviewed-by : Nilay Shroff