search

open-iscsi / rtslib-fb

Python library for configuring the Linux kernel-based multiprotocol SCSI target (LIO)
Apache License 2.0
72 stars 90 forks source link

tcmu: add support for config param data_pager_per_blk #174

Closed bostroesser closed 3 years ago

bostroesser commented 3 years ago

Starting from kernel 5.13 tcmu (user based backend) supports config parameter DataPagesPerBlk alias data_pages_per_blk.

This change enables rtslib to save the new config parameter to saveconfig.json.

Signed-off-by: Bodo Stroesser bostroesser@gmail.com

Short explanation of the new tcmu config param: The parameter allows to specify what granularity is used in data area provided via uio device. Data space now appears to userspace as chunks of data_pages_per_blk * PAGE_SIZE. If the default value 1 of data_pages_per_blk is used, tcmu behaves like unchanged.

Setting data_pages_per_blk > 1 allows tcmu to allocate less but bigger chunks, which makes allocation quicker. Also userspace will see less iovecs per data transfer. If chunk size is as big as biggest possible data transfer, userspace will see consecutive buffers only.

bostroesser commented 3 years ago

Sorry, there is a typo in the name of the commit / merge request. I will fix it and create a new request