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[src/trunk]: src/sys Rip out pserialize(9) logic now that the RCU patent has ...
details: https://anonhg.NetBSD.org/src/rev/b463eb716f0f
branches: trunk
changeset: 846866:b463eb716f0f
user: riastradh <riastradh%NetBSD.org@localhost>
date: Tue Dec 03 05:07:48 2019 +0000
description:
Rip out pserialize(9) logic now that the RCU patent has expired.
pserialize_perform() is now basically just xc_barrier(XC_HIGHPRI).
No more tentacles throughout the scheduler. Simplify the psz read
count for diagnostic assertions by putting it unconditionally into
cpu_info.
>From rmind@, tidied up by me.
diffstat:
sys/arch/mips/rmi/rmixl_cpu.c | 10 +-
sys/kern/kern_lwp.c | 8 +-
sys/kern/kern_softint.c | 8 +-
sys/kern/kern_synch.c | 8 +-
sys/kern/subr_pserialize.c | 241 +++++---------------------------------
sys/rump/librump/rumpkern/rump.c | 9 +-
sys/sys/cpu_data.h | 4 +-
sys/sys/pserialize.h | 3 +-
8 files changed, 49 insertions(+), 242 deletions(-)
diffs (truncated from 598 to 300 lines):
diff -r b6ce01f06efc -r b463eb716f0f sys/arch/mips/rmi/rmixl_cpu.c
--- a/sys/arch/mips/rmi/rmixl_cpu.c Tue Dec 03 05:01:58 2019 +0000
+++ b/sys/arch/mips/rmi/rmixl_cpu.c Tue Dec 03 05:07:48 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: rmixl_cpu.c,v 1.10 2019/12/01 15:34:45 ad Exp $ */
+/* $NetBSD: rmixl_cpu.c,v 1.11 2019/12/03 05:07:48 riastradh Exp $ */
/*
* Copyright 2002 Wasabi Systems, Inc.
@@ -38,7 +38,7 @@
#include "locators.h"
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: rmixl_cpu.c,v 1.10 2019/12/01 15:34:45 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: rmixl_cpu.c,v 1.11 2019/12/03 05:07:48 riastradh Exp $");
#include "opt_multiprocessor.h"
#include "opt_ddb.h"
@@ -414,8 +414,6 @@
{
printf("cpu_biglock_wanted %p\n", dp->cpu_biglock_wanted);
printf("cpu_callout %p\n", dp->cpu_callout);
- printf("cpu_unused1 %p\n", dp->cpu_unused1);
- printf("cpu_unused2 %d\n", dp->cpu_unused2);
printf("&cpu_schedstate %p\n", &dp->cpu_schedstate); /* TBD */
printf("&cpu_xcall %p\n", &dp->cpu_xcall); /* TBD */
printf("cpu_xcall_pending %d\n", dp->cpu_xcall_pending);
@@ -423,9 +421,7 @@
printf("cpu_lockstat %p\n", dp->cpu_lockstat);
printf("cpu_index %d\n", dp->cpu_index);
printf("cpu_biglock_count %d\n", dp->cpu_biglock_count);
- printf("cpu_spin_locks %d\n", dp->cpu_spin_locks);
- printf("cpu_simple_locks %d\n", dp->cpu_simple_locks);
- printf("cpu_spin_locks2 %d\n", dp->cpu_spin_locks2);
+ printf("cpu_psz_read_depth %d\n", dp->cpu_psz_read_depth);
printf("cpu_lkdebug_recurse %d\n", dp->cpu_lkdebug_recurse);
printf("cpu_softints %d\n", dp->cpu_softints);
printf("cpu_nsyscall %"PRIu64"\n", dp->cpu_nsyscall);
diff -r b6ce01f06efc -r b463eb716f0f sys/kern/kern_lwp.c
--- a/sys/kern/kern_lwp.c Tue Dec 03 05:01:58 2019 +0000
+++ b/sys/kern/kern_lwp.c Tue Dec 03 05:07:48 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_lwp.c,v 1.215 2019/12/01 15:27:58 ad Exp $ */
+/* $NetBSD: kern_lwp.c,v 1.216 2019/12/03 05:07:48 riastradh Exp $ */
/*-
* Copyright (c) 2001, 2006, 2007, 2008, 2009, 2019 The NetBSD Foundation, Inc.
@@ -209,7 +209,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.215 2019/12/01 15:27:58 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.216 2019/12/03 05:07:48 riastradh Exp $");
#include "opt_ddb.h"
#include "opt_lockdebug.h"
@@ -225,7 +225,6 @@
#include <sys/syscallargs.h>
#include <sys/syscall_stats.h>
#include <sys/kauth.h>
-#include <sys/pserialize.h>
#include <sys/sleepq.h>
#include <sys/lockdebug.h>
#include <sys/kmem.h>
@@ -1036,9 +1035,6 @@
pmap_activate(new_lwp);
spl0();
- /* Note trip through cpu_switchto(). */
- pserialize_switchpoint();
-
LOCKDEBUG_BARRIER(NULL, 0);
KPREEMPT_ENABLE(new_lwp);
if ((new_lwp->l_pflag & LP_MPSAFE) == 0) {
diff -r b6ce01f06efc -r b463eb716f0f sys/kern/kern_softint.c
--- a/sys/kern/kern_softint.c Tue Dec 03 05:01:58 2019 +0000
+++ b/sys/kern/kern_softint.c Tue Dec 03 05:07:48 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_softint.c,v 1.52 2019/12/01 15:34:46 ad Exp $ */
+/* $NetBSD: kern_softint.c,v 1.53 2019/12/03 05:07:48 riastradh Exp $ */
/*-
* Copyright (c) 2007, 2008, 2019 The NetBSD Foundation, Inc.
@@ -170,7 +170,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_softint.c,v 1.52 2019/12/01 15:34:46 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_softint.c,v 1.53 2019/12/03 05:07:48 riastradh Exp $");
#include <sys/param.h>
#include <sys/proc.h>
@@ -182,7 +182,6 @@
#include <sys/evcnt.h>
#include <sys/cpu.h>
#include <sys/xcall.h>
-#include <sys/pserialize.h>
#include <net/netisr.h>
@@ -884,9 +883,6 @@
l->l_pflag &= ~LP_TIMEINTR;
}
- /* Indicate a soft-interrupt switch. */
- pserialize_switchpoint();
-
/*
* If we blocked while handling the interrupt, the pinned LWP is
* gone so switch to the idle LWP. It will select a new LWP to
diff -r b6ce01f06efc -r b463eb716f0f sys/kern/kern_synch.c
--- a/sys/kern/kern_synch.c Tue Dec 03 05:01:58 2019 +0000
+++ b/sys/kern/kern_synch.c Tue Dec 03 05:07:48 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_synch.c,v 1.327 2019/12/01 15:34:46 ad Exp $ */
+/* $NetBSD: kern_synch.c,v 1.328 2019/12/03 05:07:48 riastradh Exp $ */
/*-
* Copyright (c) 1999, 2000, 2004, 2006, 2007, 2008, 2009, 2019
@@ -69,7 +69,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_synch.c,v 1.327 2019/12/01 15:34:46 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_synch.c,v 1.328 2019/12/03 05:07:48 riastradh Exp $");
#include "opt_kstack.h"
#include "opt_dtrace.h"
@@ -743,9 +743,6 @@
l->l_lwpctl->lc_pctr++;
}
- /* Note trip through cpu_switchto(). */
- pserialize_switchpoint();
-
KASSERT(l->l_cpu == ci);
splx(oldspl);
/*
@@ -755,7 +752,6 @@
retval = 1;
} else {
/* Nothing to do - just unlock and return. */
- pserialize_switchpoint();
mutex_spin_exit(spc->spc_mutex);
l->l_pflag &= ~LP_PREEMPTING;
lwp_unlock(l);
diff -r b6ce01f06efc -r b463eb716f0f sys/kern/subr_pserialize.c
--- a/sys/kern/subr_pserialize.c Tue Dec 03 05:01:58 2019 +0000
+++ b/sys/kern/subr_pserialize.c Tue Dec 03 05:07:48 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: subr_pserialize.c,v 1.13 2019/10/06 15:11:17 uwe Exp $ */
+/* $NetBSD: subr_pserialize.c,v 1.14 2019/12/03 05:07:49 riastradh Exp $ */
/*-
* Copyright (c) 2010, 2011 The NetBSD Foundation, Inc.
@@ -28,58 +28,26 @@
/*
* Passive serialization.
- *
- * Implementation accurately matches the lapsed US patent 4809168, therefore
- * code is patent-free in the United States. Your use of this code is at
- * your own risk.
- *
- * Note for NetBSD developers: all changes to this source file must be
- * approved by the <core>.
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_pserialize.c,v 1.13 2019/10/06 15:11:17 uwe Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_pserialize.c,v 1.14 2019/12/03 05:07:49 riastradh Exp $");
#include <sys/param.h>
-
-#include <sys/condvar.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/proc.h>
-#include <sys/queue.h>
#include <sys/xcall.h>
struct pserialize {
- TAILQ_ENTRY(pserialize) psz_chain;
lwp_t * psz_owner;
- kcpuset_t * psz_target;
- kcpuset_t * psz_pass;
};
-static u_int psz_work_todo __cacheline_aligned;
-static kmutex_t psz_lock __cacheline_aligned;
static struct evcnt psz_ev_excl __cacheline_aligned;
/*
- * As defined in "Method 1":
- * q0: "0 MP checkpoints have occured".
- * q1: "1 MP checkpoint has occured".
- * q2: "2 MP checkpoints have occured".
- */
-static TAILQ_HEAD(, pserialize) psz_queue0 __cacheline_aligned;
-static TAILQ_HEAD(, pserialize) psz_queue1 __cacheline_aligned;
-static TAILQ_HEAD(, pserialize) psz_queue2 __cacheline_aligned;
-
-#ifdef LOCKDEBUG
-#include <sys/percpu.h>
-
-static percpu_t *psz_debug_nreads __cacheline_aligned;
-#endif
-
-/*
* pserialize_init:
*
* Initialize passive serialization structures.
@@ -88,16 +56,8 @@
pserialize_init(void)
{
- psz_work_todo = 0;
- TAILQ_INIT(&psz_queue0);
- TAILQ_INIT(&psz_queue1);
- TAILQ_INIT(&psz_queue2);
- mutex_init(&psz_lock, MUTEX_DEFAULT, IPL_SCHED);
evcnt_attach_dynamic(&psz_ev_excl, EVCNT_TYPE_MISC, NULL,
"pserialize", "exclusive access");
-#ifdef LOCKDEBUG
- psz_debug_nreads = percpu_alloc(sizeof(uint32_t));
-#endif
}
/*
@@ -110,11 +70,7 @@
{
pserialize_t psz;
- psz = kmem_zalloc(sizeof(struct pserialize), KM_SLEEP);
- kcpuset_create(&psz->psz_target, true);
- kcpuset_create(&psz->psz_pass, true);
- psz->psz_owner = NULL;
-
+ psz = kmem_zalloc(sizeof(*psz), KM_SLEEP);
return psz;
}
@@ -128,25 +84,19 @@
{
KASSERT(psz->psz_owner == NULL);
-
- kcpuset_destroy(psz->psz_target);
- kcpuset_destroy(psz->psz_pass);
- kmem_free(psz, sizeof(struct pserialize));
+ kmem_free(psz, sizeof(*psz));
}
/*
* pserialize_perform:
*
- * Perform the write side of passive serialization. The calling
- * thread holds an exclusive lock on the data object(s) being updated.
- * We wait until every processor in the system has made at least two
- * passes through cpu_switchto(). The wait is made with the caller's
- * update lock held, but is short term.
+ * Perform the write side of passive serialization. This operation
+ * MUST be serialized at a caller level (e.g. with a mutex or by a
+ * single-threaded use).
*/
void
pserialize_perform(pserialize_t psz)
{
- int n;
KASSERT(!cpu_intr_p());
KASSERT(!cpu_softintr_p());
@@ -155,46 +105,23 @@
return;
}
KASSERT(psz->psz_owner == NULL);
- KASSERT(ncpu > 0);
if (__predict_false(mp_online == false)) {
psz_ev_excl.ev_count++;
return;
}
- /*
- * Set up the object and put it onto the queue. The lock
- * activity here provides the necessary memory barrier to
- * make the caller's data update completely visible to
- * other processors.
- */
psz->psz_owner = curlwp;
- kcpuset_copy(psz->psz_target, kcpuset_running);
- kcpuset_zero(psz->psz_pass);
-
- mutex_spin_enter(&psz_lock);
- TAILQ_INSERT_TAIL(&psz_queue0, psz, psz_chain);
- psz_work_todo++;
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