[issue1872] nfs stall (fix pushed)

[Matthew Dillon]

:Thomas Nikolajsen <thomas.nikolajsen at mail.dk> added the comment:
:
:I reduced vfs.nfs.maxasyncbio to 16 (from default of 64),
:and haven't seen the 'Insufficient sendspace' since.
:
:NFS stall can still be experienced, if I do 'too many' things at once,
:e.g. doing `git status' with repo and checkout on NFS mounts while
:doing `make -j3 buildworld' did stall NFS.
:
:Forced core dump avail. on request.
:
:Using x86_64 system also still stall NFS (above was i386);
:here forced core dump didn't work out, `panic' failed to generate core dump.

    Ok, I'm attempting to reproduce the issue.  It sounds like there is a
    code path that has a bug in it that isn't normally executed unless the
    socket buffer fills up.  Theoretically it should be ok for the socket
    buffer to limit out but it kinda sounds like data is being lost when
    that happens and causing rpcs to be lost.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>