heartbeat(9): New flag SPCF_HEARTBEATSUSPENDED.
This way we can suspend heartbeats on a single CPU while the console is in polling mode, not just when the CPU is offlined. This should be rare, so it's not _convenient_, but it should enable us to fix polling-mode console input when the hardclock timer is still running on other CPUs.
This commit is contained in:
riastradh
parent
b339b8878f
commit
572220daab
|
|
@ -1,4 +1,4 @@
|
|||
/* $NetBSD: kern_heartbeat.c,v 1.5 2023/07/16 10:18:19 riastradh Exp $ */
|
||||
/* $NetBSD: kern_heartbeat.c,v 1.6 2023/09/02 17:43:37 riastradh Exp $ */
|
||||
|
||||
/*-
|
||||
* Copyright (c) 2023 The NetBSD Foundation, Inc.
|
||||
|
|
@ -78,7 +78,7 @@
|
|||
*/
|
||||
|
||||
#include <sys/cdefs.h>
|
||||
__KERNEL_RCSID(0, "$NetBSD: kern_heartbeat.c,v 1.5 2023/07/16 10:18:19 riastradh Exp $");
|
||||
__KERNEL_RCSID(0, "$NetBSD: kern_heartbeat.c,v 1.6 2023/09/02 17:43:37 riastradh Exp $");
|
||||
|
||||
#ifdef _KERNEL_OPT
|
||||
#include "opt_ddb.h"
|
||||
|
|
@ -127,17 +127,22 @@ void *heartbeat_sih __read_mostly;
|
|||
* Suspend heartbeat monitoring of the current CPU.
|
||||
*
|
||||
* Called after the current CPU has been marked offline but before
|
||||
* it has stopped running. Caller must have preemption disabled.
|
||||
* it has stopped running, or after IPL has been raised for
|
||||
* polling-mode console input. Caller must have preemption
|
||||
* disabled. Non-nestable. Reversed by heartbeat_resume.
|
||||
*/
|
||||
void
|
||||
heartbeat_suspend(void)
|
||||
{
|
||||
struct cpu_info *ci = curcpu();
|
||||
int s;
|
||||
|
||||
KASSERT(curcpu_stable());
|
||||
KASSERT((ci->ci_schedstate.spc_flags & SPCF_HEARTBEATSUSPENDED) == 0);
|
||||
|
||||
/*
|
||||
* Nothing to do -- we just check the SPCF_OFFLINE flag.
|
||||
*/
|
||||
s = splsched();
|
||||
ci->ci_schedstate.spc_flags |= SPCF_HEARTBEATSUSPENDED;
|
||||
splx(s);
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
@ -148,6 +153,8 @@ heartbeat_suspend(void)
|
|||
* Called at startup while cold, and whenever heartbeat monitoring
|
||||
* is re-enabled after being disabled or the period is changed.
|
||||
* When not cold, ci must be the current CPU.
|
||||
*
|
||||
* Must be run at splsched.
|
||||
*/
|
||||
static void
|
||||
heartbeat_resume_cpu(struct cpu_info *ci)
|
||||
|
|
@ -155,6 +162,7 @@ heartbeat_resume_cpu(struct cpu_info *ci)
|
|||
|
||||
KASSERT(__predict_false(cold) || curcpu_stable());
|
||||
KASSERT(__predict_false(cold) || ci == curcpu());
|
||||
/* XXX KASSERT IPL_SCHED */
|
||||
|
||||
ci->ci_heartbeat_count = 0;
|
||||
ci->ci_heartbeat_uptime_cache = time_uptime;
|
||||
|
|
@ -167,9 +175,8 @@ heartbeat_resume_cpu(struct cpu_info *ci)
|
|||
* Resume heartbeat monitoring of the current CPU.
|
||||
*
|
||||
* Called after the current CPU has started running but before it
|
||||
* has been marked online. Also used internally when starting up
|
||||
* heartbeat monitoring at boot or when the maximum period is set
|
||||
* from zero to nonzero. Caller must have preemption disabled.
|
||||
* has been marked online, or when ending polling-mode input
|
||||
* before IPL is restored. Caller must have preemption disabled.
|
||||
*/
|
||||
void
|
||||
heartbeat_resume(void)
|
||||
|
|
@ -178,6 +185,7 @@ heartbeat_resume(void)
|
|||
int s;
|
||||
|
||||
KASSERT(curcpu_stable());
|
||||
KASSERT(ci->ci_schedstate.spc_flags & SPCF_HEARTBEATSUSPENDED);
|
||||
|
||||
/*
|
||||
* Block heartbeats while we reset the state so we don't
|
||||
|
|
@ -185,6 +193,7 @@ heartbeat_resume(void)
|
|||
* resetting the count and the uptime stamp.
|
||||
*/
|
||||
s = splsched();
|
||||
ci->ci_schedstate.spc_flags &= ~SPCF_HEARTBEATSUSPENDED;
|
||||
heartbeat_resume_cpu(ci);
|
||||
splx(s);
|
||||
}
|
||||
|
|
@ -198,8 +207,11 @@ heartbeat_resume(void)
|
|||
static void
|
||||
heartbeat_reset_xc(void *a, void *b)
|
||||
{
|
||||
int s;
|
||||
|
||||
heartbeat_resume();
|
||||
s = splsched();
|
||||
heartbeat_resume_cpu(curcpu());
|
||||
splx(s);
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
@ -488,7 +500,7 @@ select_patient(void)
|
|||
* in the iteration order.
|
||||
*/
|
||||
for (CPU_INFO_FOREACH(cii, ci)) {
|
||||
if (ci->ci_schedstate.spc_flags & SPCF_OFFLINE)
|
||||
if (ci->ci_schedstate.spc_flags & SPCF_HEARTBEATSUSPENDED)
|
||||
continue;
|
||||
if (passedcur) {
|
||||
/*
|
||||
|
|
@ -565,7 +577,8 @@ heartbeat(void)
|
|||
period_secs = atomic_load_relaxed(&heartbeat_max_period_secs);
|
||||
if (__predict_false(period_ticks == 0) ||
|
||||
__predict_false(period_secs == 0) ||
|
||||
__predict_false(curcpu()->ci_schedstate.spc_flags & SPCF_OFFLINE))
|
||||
__predict_false(curcpu()->ci_schedstate.spc_flags &
|
||||
SPCF_HEARTBEATSUSPENDED))
|
||||
return;
|
||||
|
||||
/*
|
||||
|
|
@ -637,8 +650,8 @@ heartbeat(void)
|
|||
* Verify that time is advancing on the patient CPU. If the
|
||||
* delta exceeds UINT_MAX/2, that means it is already ahead by
|
||||
* a little on the other CPU, and the subtraction went
|
||||
* negative, which is OK. If the CPU has been
|
||||
* offlined since we selected it, no worries.
|
||||
* negative, which is OK. If the CPU's heartbeats have been
|
||||
* suspended since we selected it, no worries.
|
||||
*
|
||||
* This uses the current CPU to ensure the other CPU has made
|
||||
* progress, even if the other CPU's hard timer interrupt
|
||||
|
|
@ -650,7 +663,8 @@ heartbeat(void)
|
|||
d = uptime - atomic_load_relaxed(&patient->ci_heartbeat_uptime_cache);
|
||||
if (__predict_false(d > period_secs) &&
|
||||
__predict_false(d < UINT_MAX/2) &&
|
||||
((patient->ci_schedstate.spc_flags & SPCF_OFFLINE) == 0))
|
||||
((patient->ci_schedstate.spc_flags & SPCF_HEARTBEATSUSPENDED)
|
||||
== 0))
|
||||
defibrillate(patient, d);
|
||||
}
|
||||
|
||||
|
|
@ -661,11 +675,21 @@ heartbeat(void)
|
|||
*/
|
||||
#ifdef DDB
|
||||
static unsigned
|
||||
db_read_unsigned(const unsigned *p)
|
||||
db_read_unsigned(const volatile unsigned *p)
|
||||
{
|
||||
unsigned x;
|
||||
|
||||
db_read_bytes((db_addr_t)p, sizeof(x), (char *)&x);
|
||||
db_read_bytes((db_addr_t)(uintptr_t)p, sizeof(x), (char *)&x);
|
||||
|
||||
return x;
|
||||
}
|
||||
|
||||
static int
|
||||
db_read_signed(const volatile int *p)
|
||||
{
|
||||
int x;
|
||||
|
||||
db_read_bytes((db_addr_t)(uintptr_t)p, sizeof(x), (char *)&x);
|
||||
|
||||
return x;
|
||||
}
|
||||
|
|
@ -677,11 +701,13 @@ heartbeat_dump(void)
|
|||
|
||||
db_printf("Heartbeats:\n");
|
||||
for (ci = db_cpu_first(); ci != NULL; ci = db_cpu_next(ci)) {
|
||||
db_printf("cpu%u: count %u uptime %u stamp %u\n",
|
||||
db_printf("cpu%u: count %u uptime %u stamp %u%s\n",
|
||||
db_read_unsigned(&ci->ci_index),
|
||||
db_read_unsigned(&ci->ci_heartbeat_count),
|
||||
db_read_unsigned(&ci->ci_heartbeat_uptime_cache),
|
||||
db_read_unsigned(&ci->ci_heartbeat_uptime_stamp));
|
||||
db_read_unsigned(&ci->ci_heartbeat_uptime_stamp),
|
||||
(db_read_signed(&ci->ci_schedstate.spc_flags) &
|
||||
SPCF_HEARTBEATSUSPENDED ? " (suspended)" : ""));
|
||||
}
|
||||
}
|
||||
#endif
|
||||
|
|
|
|||
|
|
@ -1,4 +1,4 @@
|
|||
/* $NetBSD: sched.h,v 1.92 2023/07/13 12:06:20 riastradh Exp $ */
|
||||
/* $NetBSD: sched.h,v 1.93 2023/09/02 17:43:37 riastradh Exp $ */
|
||||
|
||||
/*-
|
||||
* Copyright (c) 1999, 2000, 2001, 2002, 2007, 2008, 2019, 2020
|
||||
|
|
@ -188,6 +188,7 @@ struct schedstate_percpu {
|
|||
#define SPCF_1STCLASS 0x0040 /* first class scheduling entity */
|
||||
#define SPCF_CORE1ST 0x0100 /* first CPU in core */
|
||||
#define SPCF_PACKAGE1ST 0x0200 /* first CPU in package */
|
||||
#define SPCF_HEARTBEATSUSPENDED 0x0400 /* heartbeat (temporarily) suspended */
|
||||
|
||||
#define SPCF_SWITCHCLEAR (SPCF_SEENRR|SPCF_SHOULDYIELD)
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue