On 2019/10/15 16:05, Christoph Hellwig wrote:
On Mon, Oct 14, 2019 at 10:43:13PM +0800, yangerkun wrote:
Just set REQ_HIPRI for the last bio in iomap_dio_bio_actor. Because
multi bio created by this function can goto different cpu since this
process can be preempted by other process. And in iomap_dio_rw we will
just poll for the last bio. Fix it by only set polled for the last bio.
I agree that there is a problem with the separate poll queue now. But
doing partially polled I/O also doesn't seem very useful. Until we
can find a way to poll for multiple bios from one kiocb I think we need
to limit polling to iocbs with just a single bio. Can you look into
that? __blkdev_direct_IO do_blockdev_direct_IO probably have the same
issues. The former should be just as simple to fix, and for the latter
it might make sense to drop polling support entirely.
Thanks for your suggestion, i will try to fix it.
Thanks,
Kun.
