[dm-devel] [PATCH 7/7] dm-snapshot: use bufio prefetch

[Mikulas Patocka]

On Mon, 13 Jan 2014, Mike Snitzer wrote:

> The patch header should speak to why 12 is adequate.  Your 0th patch
> header said we should do further testing to arrive at a good value.

12 is optimal on my system (dm-loop on filesystem on 15k SCSI disk).

> I think a follow-on patch should make the 'prefetch_chunks' configurable.

I think the user wouldn't configure it anyway.

Find a configuration scenario where this request for prefetch came from 
and find the optimal value for that scenario.

> The dm_exception_store structure has a 4 byte hole before the context
> member.  Making prefetch_chunks configurable (either from table load or
> dm-snapshot module param) would help future-proof this code.

Mikulas