On Sat, Oct 28 2006, Ravi Krishnamurthy wrote:Hi all,
I have written a block driver that registers a virtual device and
routes requests to appropriate real devices after some re-mapping of
the requests. I am testing the driver by creating a filesystem on the
virtual device and copying a large number of files on to it. The test
causes the device to become unresponsive after some time. After some
debugging, I noticed that this happens only if the I/O scheduler being
used is CFQ. I have not had any trouble if the scheduler is noop,
anticipatory or deadline. The problem occurs on all the kernels I have
tested - 2.6.18-rc2, 2.6.18-rc4, 2.6.19-rc3.
The io scheduler is not obligated to recall your request handling
function, _unless_ you have no pending io at the point where
elv_next_request() returns NULL but there are things pending. IOW, when you complete your requests you want to just recall your request handling
function. Just insert something ala:
when you are done completing requests.
Does that fix it?