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lockdebug_barrier: disable preemption using the interrupt priority level, 

not crit_enter/crit_exit. Since this is called from mi_switch(), crit_exit
could recurse and skew statistics.
This commit is contained in:
ad 2008-04-27 11:28:49 +00:00
parent e33af2987c
commit 8f9c8f5ea5
1 changed files with 13 additions and 5 deletions
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18
sys/kern/subr_lockdebug.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: subr_lockdebug.c,v 1.29 2008/03/27 18:30:15 ad Exp $ */
/* $NetBSD: subr_lockdebug.c,v 1.30 2008/04/27 11:28:49 ad Exp $ */
/*-
* Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
@ -41,7 +41,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_lockdebug.c,v 1.29 2008/03/27 18:30:15 ad Exp $");
__KERNEL_RCSID(0, "$NetBSD: subr_lockdebug.c,v 1.30 2008/04/27 11:28:49 ad Exp $");
#include "opt_ddb.h"
@ -639,12 +639,17 @@ lockdebug_barrier(volatile void *spinlock, int slplocks)
struct lwp *l = curlwp;
lockdebug_t *ld;
uint16_t cpuno;
int s;
int s, s0;
if (panicstr != NULL || ld_panic)
return;
crit_enter();
/*
* Use splsoftclock() and not a critical section to block preemption.
* kpreempt_disable() will skew preemption statistics by firing again
* in mi_switch(), while we are preempting!
*/
s0 = splsoftclock();
if (curcpu()->ci_spin_locks2 != 0) {
cpuno = (uint16_t)cpu_number();
@ -656,6 +661,7 @@ lockdebug_barrier(volatile void *spinlock, int slplocks)
lockdebug_abort1(ld, &ld_spinner_lk,
__func__,
"not held by current CPU", true);
splx(s0);
return;
}
continue;
@ -663,6 +669,7 @@ lockdebug_barrier(volatile void *spinlock, int slplocks)
if (ld->ld_cpu == cpuno && (l->l_pflag & LP_INTR) == 0) {
lockdebug_abort1(ld, &ld_spinner_lk,
__func__, "spin lock held", true);
splx(s0);
return;
}
}
@ -676,6 +683,7 @@ lockdebug_barrier(volatile void *spinlock, int slplocks)
if (ld->ld_lwp == l) {
lockdebug_abort1(ld, &ld_sleeper_lk,
__func__, "sleep lock held", true);
splx(s0);
return;
}
}
@ -686,7 +694,7 @@ lockdebug_barrier(volatile void *spinlock, int slplocks)
l->l_shlocks);
}
crit_exit();
splx(s0);
}
/*