[dm-devel] dm-crypt parallelization patches

Tejun Heo tj at kernel.org
Tue Apr 9 17:57:53 UTC 2013


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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