Module Name: src
Committed By: riastradh
Date: Thu Dec 5 03:21:17 UTC 2019
Modified Files:
src/sys/kern: subr_pserialize.c
Log Message:
Restore psz_lock just for the event count.
Cost of mutex_enter/exit is negligible compared to the xcall we just
did, so this is not going to meaningfully affect performance.
To generate a diff of this commit:
cvs rdiff -u -r1.15 -r1.16 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:1.15 src/sys/kern/subr_pserialize.c:1.16
--- src/sys/kern/subr_pserialize.c:1.15 Tue Dec 3 13:30:52 2019
+++ src/sys/kern/subr_pserialize.c Thu Dec 5 03:21:17 2019
@@ -1,4 +1,4 @@
-/* $NetBSD: subr_pserialize.c,v 1.15 2019/12/03 13:30:52 martin Exp $ */
+/* $NetBSD: subr_pserialize.c,v 1.16 2019/12/05 03:21:17 riastradh Exp $ */
/*-
* Copyright (c) 2010, 2011 The NetBSD Foundation, Inc.
@@ -31,13 +31,14 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_pserialize.c,v 1.15 2019/12/03 13:30:52 martin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_pserialize.c,v 1.16 2019/12/05 03:21:17 riastradh Exp $");
#include <sys/param.h>
#include <sys/atomic.h>
#include <sys/cpu.h>
#include <sys/evcnt.h>
#include <sys/kmem.h>
+#include <sys/mutex.h>
#include <sys/pserialize.h>
#include <sys/xcall.h>
@@ -45,6 +46,7 @@ struct pserialize {
lwp_t * psz_owner;
};
+static kmutex_t psz_lock __cacheline_aligned;
static struct evcnt psz_ev_excl __cacheline_aligned;
/*
@@ -56,6 +58,7 @@ void
pserialize_init(void)
{
+ mutex_init(&psz_lock, MUTEX_DEFAULT, IPL_NONE);
evcnt_attach_dynamic(&psz_ev_excl, EVCNT_TYPE_MISC, NULL,
"pserialize", "exclusive access");
}
@@ -120,10 +123,9 @@ pserialize_perform(pserialize_t psz)
KASSERT(psz->psz_owner == curlwp);
psz->psz_owner = NULL;
-#ifdef __HAVE_ATOMIC64_LOADSTORE
- atomic_store_relaxed(&psz_ev_excl.ev_count,
- 1 + atomic_load_relaxed(&psz_ev_excl.ev_count));
-#endif
+ mutex_enter(&psz_lock);
+ psz_ev_excl.ev_count++;
+ mutex_exit(&psz_lock);
}
int
