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PR port-sparc/54718 (sparc install hangs since recent scheduler changes)

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- sched_tick: cpu_need_resched is no longer the correct thing to do here.
  All we need to do is OR the request into the local ci_want_resched.

- sched_resched_cpu: we need to set RESCHED_UPREEMPT even on softint LWPs,
  especially in the !__HAVE_FAST_SOFTINTS case, because the LWP with the
  LP_INTR flag could be running via softint_overlay() - i.e. it has been
  temporarily borrowed from a user process, and it needs to notice the
  resched after it has stopped running softints.
This commit is contained in:
ad 2019-12-01 13:20:42 +00:00
parent 43e684e6ce
commit 036b61e0aa
3 changed files with 14 additions and 19 deletions
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13
sys/kern/kern_runq.c
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@ -1,4 +1,4 @@
/* $NetBSD: kern_runq.c,v 1.50 2019/11/27 20:31:13 ad Exp $ */
/* $NetBSD: kern_runq.c,v 1.51 2019/12/01 13:20:42 ad Exp $ */
/*-
* Copyright (c) 2019 The NetBSD Foundation, Inc.
@ -56,7 +56,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_runq.c,v 1.50 2019/11/27 20:31:13 ad Exp $");
__KERNEL_RCSID(0, "$NetBSD: kern_runq.c,v 1.51 2019/12/01 13:20:42 ad Exp $");
#include "opt_dtrace.h"
@ -381,13 +381,8 @@ sched_resched_cpu(struct cpu_info *ci, pri_t pri, bool unlock)
l = ci->ci_data.cpu_onproc;
if ((l->l_flag & LW_IDLE) != 0) {
f = RESCHED_IDLE | RESCHED_UPREEMPT;
} else if ((l->l_pflag & LP_INTR) != 0) {
/* We can't currently preempt interrupt LWPs - should do. */
if (__predict_true(unlock)) {
spc_unlock(ci);
}
return;
} else if (pri >= sched_kpreempt_pri) {
} else if (pri >= sched_kpreempt_pri && (l->l_pflag & LP_INTR) == 0) {
/* We can't currently preempt softints - should be able to. */
#ifdef __HAVE_PREEMPTION
f = RESCHED_KPREEMPT;
#else

14
sys/kern/sched_4bsd.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: sched_4bsd.c,v 1.38 2019/11/29 18:29:45 ad Exp $ */
/* $NetBSD: sched_4bsd.c,v 1.39 2019/12/01 13:20:42 ad Exp $ */
/*
* Copyright (c) 1999, 2000, 2004, 2006, 2007, 2008, 2019
@ -69,7 +69,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sched_4bsd.c,v 1.38 2019/11/29 18:29:45 ad Exp $");
__KERNEL_RCSID(0, "$NetBSD: sched_4bsd.c,v 1.39 2019/12/01 13:20:42 ad Exp $");
#include "opt_ddb.h"
#include "opt_lockdebug.h"
@ -130,9 +130,9 @@ sched_tick(struct cpu_info *ci)
/* Force it into mi_switch() to look for other jobs to run. */
#ifdef __HAVE_PREEMPTION
atomic_or_uint(&l->l_dopreempt, DOPREEMPT_ACTIVE);
cpu_need_resched(ci, l, RESCHED_KPREEMPT);
atomic_or_uint(&ci->ci_want_resched, RESCHED_KPREEMPT);
#else
cpu_need_resched(ci, l, RESCHED_UPREEMPT);
atomic_or_uint(&ci->ci_want_resched, RESCHED_UPREEMPT);
#endif
break;
default:
@ -144,9 +144,9 @@ sched_tick(struct cpu_info *ci)
*/
#ifdef __HAVE_PREEMPTION
atomic_or_uint(&l->l_dopreempt, DOPREEMPT_ACTIVE);
cpu_need_resched(ci, l, RESCHED_KPREEMPT);
atomic_or_uint(&ci->ci_want_resched, RESCHED_KPREEMPT);
#else
cpu_need_resched(ci, l, RESCHED_UPREEMPT);
atomic_or_uint(&ci->ci_want_resched, RESCHED_UPREEMPT);
#endif
} else if (spc->spc_flags & SPCF_SEENRR) {
/*
@ -155,7 +155,7 @@ sched_tick(struct cpu_info *ci)
* Indicate that the process should yield.
*/
spc->spc_flags |= SPCF_SHOULDYIELD;
cpu_need_resched(ci, l, RESCHED_UPREEMPT);
atomic_or_uint(&ci->ci_want_resched, RESCHED_UPREEMPT);
} else {
spc->spc_flags |= SPCF_SEENRR;
}

6
sys/kern/sched_m2.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: sched_m2.c,v 1.34 2019/11/22 20:07:53 ad Exp $ */
/* $NetBSD: sched_m2.c,v 1.35 2019/12/01 13:20:42 ad Exp $ */
/*
* Copyright (c) 2007, 2008 Mindaugas Rasiukevicius <rmind at NetBSD org>
@ -33,7 +33,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sched_m2.c,v 1.34 2019/11/22 20:07:53 ad Exp $");
__KERNEL_RCSID(0, "$NetBSD: sched_m2.c,v 1.35 2019/12/01 13:20:42 ad Exp $");
#include <sys/param.h>
@ -330,7 +330,7 @@ sched_tick(struct cpu_info *ci)
*/
if (lwp_eprio(l) <= spc->spc_maxpriority || l->l_target_cpu) {
spc->spc_flags |= SPCF_SHOULDYIELD;
cpu_need_resched(ci, l, RESCHED_UPREEMPT);
atomic_or_uint(&ci->ci_want_resched, RESCHED_UPREEMPT);
} else
spc->spc_ticks = l->l_sched.timeslice;
lwp_unlock(l);