On 10/11/2016 06:47 PM, Paolo Bonzini wrote:
the free_sema->queue head, so set free_sema->holder as
>revelant coroutine.
NBD is using the CoMutex in a way that wasn't anticipated. The simplest
fix is to change it to CoQueue, which is like a condition variable.
Instead of locking if in_flight >= MAX_NBD_REQUESTS - 1, wait on the
queue while in_flight == MAX_NBD_REQUESTS. Instead of unlocking, use
qemu_co_queue_next to wake up one request.
Thanks for your explanation! will send out a patch later.
Thanks
-Xie
Thanks for the report!
Paolo
>For example if there are N(N=26 and MAX_NBD_REQUESTS=16) nbd write
>requests, so we'll invoke nbd_client_co_pwritev 26 times.
>time request No Actions
>1 1 in_flight=1, Coroutine=C1
>2 2 in_flight=2, Coroutine=C2
