The patch doesn't say if this is an actual bug you are seeing or
theoretical.
I've noticed this issue while running the below fio command:
fio --rw=randwrite --name=random --norandommap --ioengine=libaio
--size=16m --group_reporting --exitall --fsync_on_close=1 --invalidate=1
--direct=1 --filename=/dev/nvme2n1 --iodepth=32 --numjobs=16
--unit_base=1 --bs=4m --kb_base=1000
Note: here NVMe Host is on SIW & Target is on iw_cxgb4 and the
max_pages_per_mr supported by SIW and iw_cxgb4 are 255 and 128
respectively.
This needs to be documented in the change log.
The proposed patch enables host to advertise the max_fr_pages(via
nvme_rdma_cm_req) such that target can allocate that many number of
RW ctxs(if host's max_fr_pages is higher than target's).
As mentioned by Jason, this s a non-compatible change, if you want to
introduce this you need to go through the standard and update the
cm private_data layout (would mean that the fmt needs to increment as
well to be backward compatible).
Sure, will initiate a discussion at NVMe TWG about CM private_data format.
Will update the response soon.
As a stop-gap, nvmet needs to limit the controller mdts to how much
it can allocate based on the HCA capabilities
(max_fast_reg_page_list_len).
Sounds good, please look at capping mdts in the mean time.
