On Tue, 2019-02-19 at 09:54 -0500, Chuck Lever wrote: > Hi Trond- > > > On Feb 19, 2019, at 9:06 AM, Trond Myklebust <trondmy@xxxxxxxxx> > > wrote: > > > > Because we clear XPRT_SOCK_DATA_READY before reading, we can end up > > with a situation where new data arrives, causing xs_data_ready() to > > queue up a second receive worker job for the same socket, which > > then > > immediately gets stuck waiting on the transport receive mutex. > > The fix is to only clear XPRT_SOCK_DATA_READY once we're done > > reading, > > and then to use poll() to check if we might need to queue up a new > > job in order to deal with any new data. > > Does this fix an application-visible hang, or is it merely a > performance > optimization? I'm not aware of any hang associated with this behaviour. The patch is rather intended as an optimisation to avoid having these threads block uselessly on a mutex. -- Trond Myklebust Linux NFS client maintainer, Hammerspace trond.myklebust@xxxxxxxxxxxxxxx
