Hi Jens, I was just running xfstests on a 3.13 kernel that has had the block layer changed merged into it. generic/269 on XFS is hanging on a 2 CPU VM using virtio,cache=none for the block devices under test, with many (130+) threads stuck below submit_bio() like this:
Call Trace: [<ffffffff81adb1c9>] schedule+0x29/0x70 [<ffffffff817833ee>] percpu_ida_alloc+0x16e/0x330 [<ffffffff81759bef>] blk_mq_wait_for_tags+0x1f/0x40 [<ffffffff81758bee>] blk_mq_alloc_request_pinned+0x4e/0xf0 [<ffffffff8175931b>] blk_mq_make_request+0x3bb/0x4a0 [<ffffffff8174d2b2>] generic_make_request+0xc2/0x110 [<ffffffff8174e40c>] submit_bio+0x6c/0x120 reads and writes are hung, both data (direct and buffered) and metadata. Some IOs are sitting in io_schedule, waiting for IO completion (both buffered and direct IO, both reads and writes) so it looks like IO completion has stalled in some manner, too. Also, when I run iostat, all my virtio block devices have disappeared from it. i.e. I only see /dev/sda, and not /dev/vd[a-d] like all previous kernels have shown up. That appears to be due to /proc/diskstats not showing any stats for those devices anymore. $ cat /proc/diskstats |grep vd 253 0 vda 0 0 0 0 0 0 0 0 0 0 0 253 16 vdb 0 0 0 0 0 0 0 0 0 0 0 253 32 vdc 0 0 0 0 0 0 0 0 0 0 0 253 48 vdd 0 0 0 0 0 0 0 0 0 0 0 I have no idea if it's related to the above hang, but either way breaking iostat is a major regression.... Cheers, Dave. -- Dave Chinner da...@fromorbit.com -- 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/
