Fixes rare deadlock in user-side ucq
authorBarret Rhoden <brho@cs.berkeley.edu>
Tue, 20 Dec 2011 01:47:18 +0000 (17:47 -0800)
committerBarret Rhoden <brho@cs.berkeley.edu>
Tue, 20 Dec 2011 01:47:18 +0000 (17:47 -0800)
commitbe4ddb03c39bd4e8b072dbc28ef630afb2a383e5
tree60b700b88c2b15bf2c74ce3c85c8756ec300a897
parentcd23d2f72688849540355b1911affc4a82412025
Fixes rare deadlock in user-side ucq

In that loop, we spin on userspace.  If that vcore was preempted in its
short window (message reception), and we were the last vcore, and we got
to the spinning loop before getting the preempt message, then we'd
deadlock.  Side note: this hasn't happened yet.
user/parlib/ucq.c