On Tue, 9 Apr 2013, Tejun Heo wrote:
> 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? What do you mean? I used to have a patch that keeps order of requests as they were introduced, but sorting the requests according to sector number is a bit simpler. > > 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. bio_associate_current() is only valid on a system with cgroups and there are no cgroups on the kernel where I tested it. It is an empty function: static inline int bio_associate_current(struct bio *bio) { return -ENOENT; } Mikulas > Thanks. > > -- > tejun > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/