[src/trunk]: src/sys/kern lwp_create:

[ad <ad%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/7ace0f0b671c
branches:  trunk
changeset: 461276:7ace0f0b671c
user:      ad <ad%NetBSD.org@localhost>
date:      Thu Nov 21 18:22:05 2019 +0000

description:
lwp_create:
- Don't need to check for PK_SYSTEM when inheriting an affinity mask.
- Inherit processor set ID under proc_lock, to sync with pset syscalls.

diffstat:

 sys/kern/kern_lwp.c |  34 ++++++++++++++--------------------
 1 files changed, 14 insertions(+), 20 deletions(-)

diffs (64 lines):

diff -r 13a8ab18896e -r 7ace0f0b671c sys/kern/kern_lwp.c
--- a/sys/kern/kern_lwp.c       Thu Nov 21 18:17:36 2019 +0000
+++ b/sys/kern/kern_lwp.c       Thu Nov 21 18:22:05 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_lwp.c,v 1.209 2019/11/21 18:17:36 ad Exp $        */
+/*     $NetBSD: kern_lwp.c,v 1.210 2019/11/21 18:22:05 ad Exp $        */
 
 /*-
  * Copyright (c) 2001, 2006, 2007, 2008, 2009, 2019 The NetBSD Foundation, Inc.
@@ -211,7 +211,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.209 2019/11/21 18:17:36 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.210 2019/11/21 18:22:05 ad Exp $");
 
 #include "opt_ddb.h"
 #include "opt_lockdebug.h"
@@ -952,26 +952,18 @@
 
        KASSERT(l2->l_affinity == NULL);
 
-       if ((p2->p_flag & PK_SYSTEM) == 0) {
-               /* Inherit the affinity mask. */
+       /* Inherit the affinity mask. */
+       if (l1->l_affinity) {
+               /*
+                * Note that we hold the state lock while inheriting
+                * the affinity to avoid race with sched_setaffinity().
+                */
+               lwp_lock(l1);
                if (l1->l_affinity) {
-                       /*
-                        * Note that we hold the state lock while inheriting
-                        * the affinity to avoid race with sched_setaffinity().
-                        */
-                       lwp_lock(l1);
-                       if (l1->l_affinity) {
-                               kcpuset_use(l1->l_affinity);
-                               l2->l_affinity = l1->l_affinity;
-                       }
-                       lwp_unlock(l1);
+                       kcpuset_use(l1->l_affinity);
+                       l2->l_affinity = l1->l_affinity;
                }
-               lwp_lock(l2);
-               /* Inherit a processor-set */
-               l2->l_psid = l1->l_psid;
-               /* Look for a CPU to start */
-               l2->l_cpu = sched_takecpu(l2);
-               lwp_unlock_to(l2, l2->l_cpu->ci_schedstate.spc_mutex);
+               lwp_unlock(l1);
        }
        mutex_exit(p2->p_lock);
 
@@ -979,6 +971,8 @@
 
        mutex_enter(proc_lock);
        LIST_INSERT_HEAD(&alllwp, l2, l_list);
+       /* Inherit a processor-set */
+       l2->l_psid = l1->l_psid;
        mutex_exit(proc_lock);
 
        SYSCALL_TIME_LWP_INIT(l2);