Module Name: src
Committed By: riz
Date: Mon Feb 11 20:42:32 UTC 2013
Modified Files:
src/sys/kern [netbsd-6]: subr_pserialize.c
Log Message:
Pull up following revision(s) (requested by rmind in ticket #811):
sys/kern/subr_pserialize.c: revision 1.7
- pserialize_switchpoint: check for passing twice, not more than needed.
- pserialize_perform: avoid a possible race with softint handler.
Reported by hannken@.
To generate a diff of this commit:
cvs rdiff -u -r1.5.2.1 -r1.5.2.2 src/sys/kern/subr_pserialize.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/subr_pserialize.c
diff -u src/sys/kern/subr_pserialize.c:1.5.2.1 src/sys/kern/subr_pserialize.c:1.5.2.2
--- src/sys/kern/subr_pserialize.c:1.5.2.1 Fri Feb 8 19:32:07 2013
+++ src/sys/kern/subr_pserialize.c Mon Feb 11 20:42:32 2013
@@ -1,4 +1,4 @@
-/* $NetBSD: subr_pserialize.c,v 1.5.2.1 2013/02/08 19:32:07 riz Exp $ */
+/* $NetBSD: subr_pserialize.c,v 1.5.2.2 2013/02/11 20:42:32 riz Exp $ */
/*-
* Copyright (c) 2010, 2011 The NetBSD Foundation, Inc.
@@ -38,7 +38,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_pserialize.c,v 1.5.2.1 2013/02/08 19:32:07 riz Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_pserialize.c,v 1.5.2.2 2013/02/11 20:42:32 riz Exp $");
#include <sys/param.h>
@@ -48,13 +48,13 @@ __KERNEL_RCSID(0, "$NetBSD: subr_pserial
#include <sys/kmem.h>
#include <sys/mutex.h>
#include <sys/pserialize.h>
+#include <sys/proc.h>
#include <sys/queue.h>
#include <sys/xcall.h>
struct pserialize {
TAILQ_ENTRY(pserialize) psz_chain;
lwp_t * psz_owner;
- kcondvar_t psz_notifier;
kcpuset_t * psz_target;
kcpuset_t * psz_pass;
};
@@ -102,7 +102,6 @@ pserialize_create(void)
pserialize_t psz;
psz = kmem_zalloc(sizeof(struct pserialize), KM_SLEEP);
- cv_init(&psz->psz_notifier, "psrlz");
kcpuset_create(&psz->psz_target, true);
kcpuset_create(&psz->psz_pass, true);
psz->psz_owner = NULL;
@@ -121,7 +120,6 @@ pserialize_destroy(pserialize_t psz)
KASSERT(psz->psz_owner == NULL);
- cv_destroy(&psz->psz_notifier);
kcpuset_destroy(psz->psz_target);
kcpuset_destroy(psz->psz_pass);
kmem_free(psz, sizeof(struct pserialize));
@@ -163,27 +161,21 @@ pserialize_perform(pserialize_t psz)
mutex_spin_enter(&psz_lock);
TAILQ_INSERT_TAIL(&psz_queue0, psz, psz_chain);
psz_work_todo++;
- mutex_spin_exit(&psz_lock);
- /*
- * Force some context switch activity on every CPU, as the system
- * may not be busy. Note: should pass the point twice.
- */
- xc = xc_broadcast(XC_HIGHPRI, (xcfunc_t)nullop, NULL, NULL);
- xc_wait(xc);
+ do {
+ mutex_spin_exit(&psz_lock);
- /* No need to xc_wait() as we implement our own condvar. */
- xc_broadcast(XC_HIGHPRI, (xcfunc_t)nullop, NULL, NULL);
+ /*
+ * Force some context switch activity on every CPU, as
+ * the system may not be busy. Pause to not flood.
+ */
+ xc = xc_broadcast(XC_HIGHPRI, (xcfunc_t)nullop, NULL, NULL);
+ xc_wait(xc);
+ kpause("psrlz", false, 1, NULL);
+
+ mutex_spin_enter(&psz_lock);
+ } while (!kcpuset_iszero(psz->psz_target));
- /*
- * Wait for all CPUs to cycle through mi_switch() twice.
- * The last one through will remove our update from the
- * queue and awaken us.
- */
- mutex_spin_enter(&psz_lock);
- while (!kcpuset_iszero(psz->psz_target)) {
- cv_wait(&psz->psz_notifier, &psz_lock);
- }
psz_ev_excl.ev_count++;
mutex_spin_exit(&psz_lock);
@@ -236,8 +228,8 @@ pserialize_switchpoint(void)
*/
for (psz = TAILQ_FIRST(&psz_queue1); psz != NULL; psz = next) {
next = TAILQ_NEXT(psz, psz_chain);
+ kcpuset_set(psz->psz_pass, cid);
if (!kcpuset_match(psz->psz_pass, psz->psz_target)) {
- kcpuset_set(psz->psz_pass, cid);
continue;
}
kcpuset_zero(psz->psz_pass);
@@ -250,8 +242,8 @@ pserialize_switchpoint(void)
*/
for (psz = TAILQ_FIRST(&psz_queue0); psz != NULL; psz = next) {
next = TAILQ_NEXT(psz, psz_chain);
+ kcpuset_set(psz->psz_pass, cid);
if (!kcpuset_match(psz->psz_pass, psz->psz_target)) {
- kcpuset_set(psz->psz_pass, cid);
continue;
}
kcpuset_zero(psz->psz_pass);
@@ -265,7 +257,6 @@ pserialize_switchpoint(void)
while ((psz = TAILQ_FIRST(&psz_queue2)) != NULL) {
TAILQ_REMOVE(&psz_queue2, psz, psz_chain);
kcpuset_zero(psz->psz_target);
- cv_signal(&psz->psz_notifier);
psz_work_todo--;
}
mutex_spin_exit(&psz_lock);
