tree 317c9a9c921b34adfca46b494e446fdb212def69
parent bfa12a51940bfa20432778a9dd4b4e2865a8c3be
author Suharsh Sivakumar <suharshs@google.com> 1430376699 -0700
committer Suharsh Sivakumar <suharshs@google.com> 1430376711 -0700

rpc/stream/vif: Concurrent mgr.FindOrDialVIFs should share VIF cache.

Before this change, concurrent mgr.FindOrDialVIFs would all create
separate VIFs because they would skip passed the vifSet.Find and Dial
a VIF before the vifSet gets populated.
This was being seen in a JS test that concurrently create 22 Servers
whose attempts to mount were taking forever, even though they shared
the same client for mounting.

The solution in this CL is to introduce a vif.Set.BlockingFind that
blocks if it knows another thread is going Dial the VIF to the desired
network and address shortly.

This guarantees that only one VIF will be created per (network,address)

Note: something similar will need to be done in the vcMap in client.go
as well.

Change-Id: Iaa422467c1df132ed0902db4ccd2e7a3e7f7c24d