svn commit: r232756 - stable/9/sys/kern

[Ryan Stone]

Author: rstone
Date: Sat Mar 10 02:26:12 2012
New Revision: 232756
URL: http://svn.freebsd.org/changeset/base/232756

Log:
  MFC r230984:
  
   Whenever a new kernel thread is spawned, explicitly clear any CPU affinity
   set on the new thread.  This prevents the thread from inadvertently
   inheriting affinity from a random sibling.

Modified:
  stable/9/sys/kern/kern_kthread.c
Directory Properties:
  stable/9/sys/   (props changed)

Modified: stable/9/sys/kern/kern_kthread.c
==============================================================================
--- stable/9/sys/kern/kern_kthread.c	Sat Mar 10 01:36:42 2012	(r232755)
+++ stable/9/sys/kern/kern_kthread.c	Sat Mar 10 02:26:12 2012	(r232756)
@@ -29,6 +29,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/cpuset.h>
 #include <sys/kthread.h>
 #include <sys/lock.h>
 #include <sys/mutex.h>
@@ -117,6 +118,9 @@ kproc_create(void (*func)(void *), void 
 
 	/* call the processes' main()... */
 	cpu_set_fork_handler(td, func, arg);
+
+	/* Avoid inheriting affinity from a random parent. */
+	cpuset_setthread(td->td_tid, cpuset_root);
 	thread_lock(td);
 	TD_SET_CAN_RUN(td);
 	sched_prio(td, PVM);
@@ -299,6 +303,9 @@ kthread_add(void (*func)(void *), void *
 
 	tidhash_add(newtd);
 
+	/* Avoid inheriting affinity from a random parent. */
+	cpuset_setthread(newtd->td_tid, cpuset_root);
+
 	/* Delay putting it on the run queue until now. */
 	if (!(flags & RFSTOPPED)) {
 		thread_lock(newtd);