From: Matthew Dillon <dillon@apollo.backplane.com>
Date: Tue, 4 Jan 2011 04:22:47 +0000 (-0800)
Subject: kernel - Fix vkernel lwp stuck thread bug
X-Git-Tag: v2.11.0~397
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/7e8888ce7f674f2071ff724ef17afa053eadd953

kernel - Fix vkernel lwp stuck thread bug

* Fix a tsleep hz / 100 which calculates to 0 due to the vkernel's 20hz
  tick rate.  This could cause threads running under the vkernel to get
  stuck.
---

diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index 55b520740f..2c26b8549a 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -2043,7 +2043,8 @@ restart:
 		/*
 		 * Sanity Checks
 		 */
-		KASSERT(bp->b_qindex == qindex, ("getnewbuf: inconsistent queue %d bp %p", qindex, bp));
+		KASSERT(bp->b_qindex == qindex,
+			("getnewbuf: inconsistent queue %d bp %p", qindex, bp));
 
 		/*
 		 * Note: we no longer distinguish between VMIO and non-VMIO
@@ -2081,7 +2082,7 @@ restart:
 
 		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT) != 0) {
 			spin_unlock(&bufqspin);
-			tsleep(&bd_request, 0, "gnbxxx", hz / 100);
+			tsleep(&bd_request, 0, "gnbxxx", (hz + 99) / 100);
 			goto restart;
 		}
 		if (bp->b_qindex != qindex) {