[LU-14392] gnilnd: re-enable large I/o buffers

Mon, 13 Dec 2021 15:16:55 +0000

Currently contiguous memory in lnet_md_build() is split into pages for described by an array of bio_vec entries.
Previously DVS would pass large buffers (~2.5M) through lnet (via gnilnd) as a single iovec entry. However this now (indirectly) breaks the 1M handshake of LNET_MAX_IOV being 256 (1 page of bio_vec) which is enforced in parts of LNet.
Here we make a new GNILND_MAX_IOV with a 4M i/o maximum and pass a hint through that LNet should accept the large buffer w/o complaint.

Whamcloud Community JIRA

[LU-14392] gnilnd: re-enable large I/o buffers