Re: [dm-devel] Re: [PATCH 12/17] bottom-layer barrier support

[Mikulas Patocka <mpatocka redhat com>]

On Tue, 28 Apr 2009, Alasdair G Kergon wrote:

> On Mon, Apr 27, 2009 at 07:41:47PM -0400, Mikulas Patocka wrote:
> > There is separate read_delay and write_delay. Flushes are governed by 
> > write_delay.
>  
> And the value of read_delay has no impact on the flush?

No.

> (Because of the "wait for all outstanding I/O" bit that eventually I
> want to see removed to facilitate true barrier passing?)

With dm-delay, "true barrier passing" doesn't have sense. Dm-delay is 
designed to delay requests, so no one wants high performance from it :)

> Alasdair
> -- 
> agk redhat com

Mikulas