From: Matthew Dillon <dillon@apollo.backplane.com>
Date: Mon, 31 Jan 2011 21:08:26 +0000 (-0800)
Subject: kernel - Fix stall after mountroot w/ SMP & ncpus == 1
X-Git-Tag: v2.11.0~268^2~6
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/58bb3381c4471bee358b69dec424840490348f65

kernel - Fix stall after mountroot w/ SMP & ncpus == 1

* Fix a degenerate case for SMP builds when ncpus == 1.  This effects
  both the vkernel and the normal kernel (when a SMP kernel is booted
  on a non-SMP box which has a LAPIC).

  The init process was not bring scheduled properly.
---

diff --git a/sys/kern/usched_bsd4.c b/sys/kern/usched_bsd4.c
index 29dd464152..1f9fe999fc 100644
--- a/sys/kern/usched_bsd4.c
+++ b/sys/kern/usched_bsd4.c
@@ -553,8 +553,13 @@ bsd4_setrunqueue(struct lwp *lp)
 found:
 	if (gd == mycpu) {
 		spin_unlock(&bsd4_spin);
-		if ((dd->upri & ~PPQMASK) > (lp->lwp_priority & ~PPQMASK))
-			need_user_resched();
+		if ((dd->upri & ~PPQMASK) > (lp->lwp_priority & ~PPQMASK)) {
+			if (dd->uschedcp == NULL) {
+				lwkt_schedule(&dd->helper_thread);
+			} else {
+				need_user_resched();
+			}
+		}
 	} else {
 		atomic_clear_cpumask(&bsd4_rdyprocmask, CPUMASK(cpuid));
 		spin_unlock(&bsd4_spin);