Re: dm-crypt parallelization patches

From: Tejun Heo
Date: Tue Apr 09 2013 - 13:58:06 EST


On Tue, Apr 09, 2013 at 01:51:43PM -0400, Mikulas Patocka wrote:
> The patch dm-crypt-sort-requests.patch sorts write requests submitted by a
> single thread. The requests are sorted according to the sector number,
> rb-tree is used for efficient sorting.

Hmmm? Why not just keep the issuing order along with plugging
boundaries?

> So it seems that CFQ has some deficiency that it cannot merge adjacent
> requests done by different processes.

As I wrote before, please use bio_associate_current(). Currently,
dm-crypt is completely messing up all the context information that cfq
depends on to schedule IOs. Of course, it doesn't perform well.

Thanks.

--
tejun
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