On 3/31/2021 4:31 PM, Chuck Lever wrote:
On Wed, Mar 31, 2021 at 4:01 PM Tom Talpey <tom@xxxxxxxxxx> wrote:
On 3/31/2021 3:36 PM, Chuck Lever wrote:
Currently the Receive completion handler refreshes the Receive Queue
whenever a successful Receive completion occurs.
On disconnect, xprtrdma drains the Receive Queue. The first few
Receive completions after a disconnect are typically successful,
until the first flushed Receive.
snip
Is it not possible to mark the WRs as
being part of a batch, and allowing them to flush? You could borrow a
bit in the completion cookie, and check it when the CQE pops out. Maybe.
It's not an issue with batching, it's an issue with posting Receives from the
Receive completion handler. I'd think that any of the ULPs that post Receives
in their completion handler would have the same issue.
The purpose of the QP drain in rpcrdma_xprt_disconnect() is to ensure there
are no more WRs in flight so that the hardware resources can be safely
destroyed. If the Receive completion handler continues to post Receive WRs
after the drain sentinel has been posted, leaks and crashes become possible.
Well, why not do an atomic_set() of a flag just before posting the
sentinel, and check it with atomic_get() before any other RQ post?
Tom.
