[dm-devel] A target to just process bios background?

Akira Hayakawa hayakawa at valinux.co.jp
Tue Mar 4 01:30:37 UTC 2014


Hi,

Is it meaningless to submit the split and cloned bios in background
using workqueue?

device-mapper doesn't go to next split before the .map hook returns
(and generic_make_request() returns only in case of DM_MAPIO_REMAPPED).
So, quitting from .map hook and going into next split fast sounds to me
effective at least in terms of CPU usage (in multicore system).

is this discussed before?

A target as tiny as linear or flakey can be thought:
- it has work_struct in per_bio_data
- .map hook queue_work the work into private wq.
- and then return DM_MAPIO_SUBMITTED

is this implemented before?

I think this target will make people happy if they
want to see what if the bio submission is done background
without changing their code but only stacking a dm target.

I am sorry if I am confused.

-- 
Akira




More information about the dm-devel mailing list