Remove locking of p_stmutex from sched_pstats(), protect l_pctcpu with p_lock,
and make l_cpticks lock-less. Should fix PR/38296. Reviewed (slightly different version) by <ad>.
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rmind
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14071b7c24
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61fc86b29b
@ -1,4 +1,4 @@
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/* $NetBSD: kern_clock.c,v 1.124 2008/06/01 21:24:15 ad Exp $ */
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/* $NetBSD: kern_clock.c,v 1.125 2008/07/02 19:38:37 rmind Exp $ */
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/*-
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* Copyright (c) 2000, 2004, 2006, 2007, 2008 The NetBSD Foundation, Inc.
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@ -69,7 +69,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: kern_clock.c,v 1.124 2008/06/01 21:24:15 ad Exp $");
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__KERNEL_RCSID(0, "$NetBSD: kern_clock.c,v 1.125 2008/07/02 19:38:37 rmind Exp $");
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#include "opt_ntp.h"
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#include "opt_perfctrs.h"
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@ -446,7 +446,7 @@ statclock(struct clockframe *frame)
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spc->spc_pscnt = psdiv;
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if (p != NULL) {
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++l->l_cpticks;
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atomic_inc_uint(&l->l_cpticks);
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mutex_spin_exit(&p->p_stmutex);
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}
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}
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@ -1,4 +1,4 @@
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/* $NetBSD: kern_synch.c,v 1.248 2008/05/31 21:26:01 ad Exp $ */
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/* $NetBSD: kern_synch.c,v 1.249 2008/07/02 19:38:37 rmind Exp $ */
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/*-
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* Copyright (c) 1999, 2000, 2004, 2006, 2007, 2008 The NetBSD Foundation, Inc.
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@ -68,7 +68,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: kern_synch.c,v 1.248 2008/05/31 21:26:01 ad Exp $");
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__KERNEL_RCSID(0, "$NetBSD: kern_synch.c,v 1.249 2008/07/02 19:38:37 rmind Exp $");
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#include "opt_kstack.h"
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#include "opt_perfctrs.h"
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@ -1163,17 +1163,20 @@ fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
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void
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sched_pstats(void *arg)
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{
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const int clkhz = (stathz != 0 ? stathz : hz);
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struct rlimit *rlim;
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struct lwp *l;
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struct proc *p;
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int sig, clkhz;
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long runtm;
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fixpt_t lpctcpu;
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u_int lcpticks;
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int sig;
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sched_pstats_ticks++;
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mutex_enter(proc_lock);
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PROCLIST_FOREACH(p, &allproc) {
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if ((p->p_flag & PK_MARKER) != 0)
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if (__predict_false((p->p_flag & PK_MARKER) != 0))
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continue;
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/*
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@ -1182,10 +1185,9 @@ sched_pstats(void *arg)
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* (remember them?) overflow takes 45 days.
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*/
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mutex_enter(p->p_lock);
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mutex_spin_enter(&p->p_stmutex);
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runtm = p->p_rtime.sec;
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LIST_FOREACH(l, &p->p_lwps, l_sibling) {
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if ((l->l_flag & LW_IDLE) != 0)
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if (__predict_false((l->l_flag & LW_IDLE) != 0))
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continue;
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lwp_lock(l);
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runtm += l->l_rtime.sec;
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@ -1193,27 +1195,26 @@ sched_pstats(void *arg)
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sched_lwp_stats(l);
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lwp_unlock(l);
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/*
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* p_pctcpu is only for ps.
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*/
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l->l_pctcpu = (l->l_pctcpu * ccpu) >> FSHIFT;
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if (l->l_slptime < 1) {
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clkhz = stathz != 0 ? stathz : hz;
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if (l->l_slptime != 0)
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continue;
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lpctcpu = l->l_pctcpu;
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lcpticks = atomic_swap_uint(&l->l_cpticks, 0);
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#if (FSHIFT >= CCPU_SHIFT)
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l->l_pctcpu += (clkhz == 100) ?
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((fixpt_t)l->l_cpticks) <<
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(FSHIFT - CCPU_SHIFT) :
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100 * (((fixpt_t) p->p_cpticks)
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<< (FSHIFT - CCPU_SHIFT)) / clkhz;
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lpctcpu += (clkhz == 100) ?
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((fixpt_t)lcpticks) <<
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(FSHIFT - CCPU_SHIFT) :
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100 * (((fixpt_t) p->p_cpticks)
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<< (FSHIFT - CCPU_SHIFT)) / clkhz;
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#else
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l->l_pctcpu += ((FSCALE - ccpu) *
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(l->l_cpticks * FSCALE / clkhz)) >> FSHIFT;
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lpctcpu += ((FSCALE - ccpu) *
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(lcpticks * FSCALE / clkhz)) >> FSHIFT;
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#endif
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l->l_cpticks = 0;
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}
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l->l_pctcpu = lpctcpu;
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}
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/* Calculating p_pctcpu only for ps(1) */
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p->p_pctcpu = (p->p_pctcpu * ccpu) >> FSHIFT;
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mutex_spin_exit(&p->p_stmutex);
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/*
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* Check if the process exceeds its CPU resource allocation.
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@ -1221,7 +1222,7 @@ sched_pstats(void *arg)
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*/
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rlim = &p->p_rlimit[RLIMIT_CPU];
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sig = 0;
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if (runtm >= rlim->rlim_cur) {
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if (__predict_false(runtm >= rlim->rlim_cur)) {
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if (runtm >= rlim->rlim_max)
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sig = SIGKILL;
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else {
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@ -1231,7 +1232,7 @@ sched_pstats(void *arg)
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}
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}
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mutex_exit(p->p_lock);
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if (sig)
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if (__predict_false(sig))
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psignal(p, sig);
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}
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mutex_exit(proc_lock);
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@ -1,4 +1,4 @@
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/* $NetBSD: lwp.h,v 1.102 2008/06/22 00:06:36 christos Exp $ */
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/* $NetBSD: lwp.h,v 1.103 2008/07/02 19:38:37 rmind Exp $ */
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/*-
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* Copyright (c) 2001, 2006, 2007, 2008 The NetBSD Foundation, Inc.
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@ -57,7 +57,6 @@
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* l: *l_mutex
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* p: l_proc->p_lock
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* s: spc_mutex, which may or may not be referenced by l_mutex
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* t: l_proc->p_stmutex
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* S: l_selcpu->sc_lock
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* (: unlocked, stable
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* !: unlocked, may only be reliably accessed by the LWP itself
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@ -96,8 +95,8 @@ struct lwp {
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SLIST_HEAD(, turnstile) l_pi_lenders; /* l: ts lending us priority */
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uint64_t l_ncsw; /* l: total context switches */
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uint64_t l_nivcsw; /* l: involuntary context switches */
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int l_cpticks; /* t: Ticks of CPU time */
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fixpt_t l_pctcpu; /* t: %cpu during l_swtime */
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u_int l_cpticks; /* (: Ticks of CPU time */
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fixpt_t l_pctcpu; /* p: %cpu during l_swtime */
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fixpt_t l_estcpu; /* l: cpu time for SCHED_4BSD */
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psetid_t l_psid; /* l: assigned processor-set ID */
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struct cpu_info *l_target_cpu; /* l: target CPU to migrate */
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