Re: [PATCH v4 0/7] nbd: eliminate queue freeze/unfreeze overhead in connection setup

Hi,

https://sashiko.dev/#/patchset/20260727074718.414868-1-yangerkun%40huawei.com

Sashiko has identified some problems in this series. I will address them 
in the next version. Please disregard this version. Thank you!

Thanks,
Erkun.

在 2026/7/27 15:47, Yang Erkun 写道:
> This series eliminates the blk_mq_freeze_queue()/unfreeze_queue()
> overhead that currently occurs during nbd connection setup(nbd provide
> ondemand and was using in AI sandbox e2b[1] to mount and attach rootfs).
> Each freeze cycle will introduce a RCU grace which was significant
> with multi-core system.
> 
> time nbd-client --name myexport --connections 96 127.0.0.1 1234
> 
> After this patchset:
> real    0m0.090s
> user    0m0.004s
> sys     0m0.018s
> 
> Without this patchset:
> real    0m2.195s
> user    0m0.005s
> sys     0m0.022s
> 
> v3->v4:
> 
> 1. factor out nbd_genl_foreach_sock to cleanup duplicated code
> 2. rewrite some commit message to make what's going more clearly
> 
> v2->v3:
> 1. Stop using xarray, and protect it by rejecting late NBD_SET_SOCKS
> 2. Eliminate freeze in nbd_set_size when device setup
> 3. Add module parameter to eliminate freeze for pre-created device
> 
> v1->v2:
> 1. Rewrite cover letter
> 2. Eliminate freeze call from blk_mq_update_nr_hw_queues in
>     nbd_start_device for netlink path
> 
> 
> Long Li (1):
>    nbd: simplify find_fallback() by removing redundant logic
> 
> Yang Erkun (6):
>    nbd: disallow NBD_SET_SOCK on an active device
>    nbd: remove queue freeze in nbd_add_socket
>    nbd: skip queue freeze when setting size at device startup
>    nbd: factor out a nbd_genl_foreach_sock
>    nbd: remove queue freeze for newly created nbd from netlink path
>    nbd: add nr_hw_queues module parameter for pre-created devices
> 
>   drivers/block/nbd.c | 228 +++++++++++++++++++++++---------------------
>   1 file changed, 121 insertions(+), 107 deletions(-)
>