Module Name: src
Committed By: thorpej
Date: Tue Dec 21 19:00:38 UTC 2021
Modified Files:
src/sys/kern: kern_lwp.c
Log Message:
Rather than calling xc_barrier() in lwp_dtor(), set a pre-destruct hook
on the lwp_cache and invoke the barrier there.
To generate a diff of this commit:
cvs rdiff -u -r1.244 -r1.245 src/sys/kern/kern_lwp.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/kern_lwp.c
diff -u src/sys/kern/kern_lwp.c:1.244 src/sys/kern/kern_lwp.c:1.245
--- src/sys/kern/kern_lwp.c:1.244 Tue Sep 28 15:05:42 2021
+++ src/sys/kern/kern_lwp.c Tue Dec 21 19:00:37 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_lwp.c,v 1.244 2021/09/28 15:05:42 thorpej Exp $ */
+/* $NetBSD: kern_lwp.c,v 1.245 2021/12/21 19:00:37 thorpej Exp $ */
/*-
* Copyright (c) 2001, 2006, 2007, 2008, 2009, 2019, 2020
@@ -217,7 +217,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.244 2021/09/28 15:05:42 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.245 2021/12/21 19:00:37 thorpej Exp $");
#include "opt_ddb.h"
#include "opt_lockdebug.h"
@@ -262,6 +262,7 @@ struct lwplist alllwp __cacheline_alig
static int lwp_ctor(void *, void *, int);
static void lwp_dtor(void *, void *);
+static void lwp_pre_dtor(void *);
/* DTrace proc provider probes */
SDT_PROVIDER_DEFINE(proc);
@@ -341,6 +342,7 @@ lwpinit(void)
lwpinit_specificdata();
lwp_cache = pool_cache_init(sizeof(lwp_t), MIN_LWP_ALIGNMENT, 0, 0,
"lwppl", NULL, IPL_NONE, lwp_ctor, lwp_dtor, NULL);
+ pool_cache_setpredestruct(lwp_cache, lwp_pre_dtor);
maxlwp = cpu_maxlwp();
sysctl_kern_lwp_setup();
@@ -391,23 +393,29 @@ lwp_ctor(void *arg, void *obj, int flags
}
static void
-lwp_dtor(void *arg, void *obj)
+lwp_pre_dtor(void *arg __unused)
{
- lwp_t *l = obj;
- (void)l;
-
/*
* Provide a barrier to ensure that all mutex_oncpu() and rw_oncpu()
- * calls will exit before memory of LWP is returned to the pool, where
+ * calls will exit before memory of LWPs is returned to the pool, where
* KVA of LWP structure might be freed and re-used for other purposes.
* Kernel preemption is disabled around mutex_oncpu() and rw_oncpu()
- * callers, therefore cross-call to all CPUs will do the job. Also,
- * the value of l->l_cpu must be still valid at this point.
+ * callers, therefore cross-call to all CPUs will do the job.
*
* XXX should use epoch based reclamation.
*/
- KASSERT(l->l_cpu != NULL);
xc_barrier(0);
+}
+
+static void
+lwp_dtor(void *arg, void *obj)
+{
+ lwp_t *l = obj;
+
+ /*
+ * The value of l->l_cpu must still be valid at this point.
+ */
+ KASSERT(l->l_cpu != NULL);
/*
* We can't return turnstile0 to the pool (it didn't come from it),
