[LU-11449] osc: send RPCs with random i/o

Related — Wed, 17 Feb 2021 21:05:59 +0000

~~LU-8515~~ modified osc_makes_rpc to remove a check which sent RPCs once the total number of pages == max_pages_per_rpc. This fixed an issue with > 1 writer per stripe where smaller, fragmented RPCs would be sent instead of full size RPCs.

However, it introduced a different issue with small random writes, particularly when sparse. Because small random writes will (in the large file/sparse case) not make complete, contiguous extents, no RPCs will be sent until the max_dirty_mb or grant limit is hit.

This means that in the small-random-sparse write case not enough RPCs will be sent.

The solution is to add an additional check for greater than max_pages_per_rpc pages. Details in patch.

Whamcloud Community JIRA

[LU-11449] osc: send RPCs with random i/o