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authorad <ad@NetBSD.org>2008-03-10 13:36:22 +0000
committerad <ad@NetBSD.org>2008-03-10 13:36:22 +0000
commit8228d024b77bbc4e5467e02c7f1c0bc239d630d8 (patch)
treed1745bbad13234a1678997591da1b6394b76b0e9 /sys
parentee76f56f7043ab793e5d63ef84cc9526a0194347 (diff)
Use atomics to maintain the number of special page references. Should fix
locking problems including in revision 1.232.
Diffstat (limited to 'sys')
-rw-r--r--sys/arch/alpha/alpha/pmap.c52
-rw-r--r--sys/arch/alpha/include/vmparam.h4
2 files changed, 13 insertions, 43 deletions
diff --git a/sys/arch/alpha/alpha/pmap.c b/sys/arch/alpha/alpha/pmap.c
index 24102b6a56a..30b3ff908ac 100644
--- a/sys/arch/alpha/alpha/pmap.c
+++ b/sys/arch/alpha/alpha/pmap.c
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.c,v 1.232 2008/02/21 17:12:58 ad Exp $ */
+/* $NetBSD: pmap.c,v 1.233 2008/03/10 13:36:22 ad Exp $ */
/*-
* Copyright (c) 1998, 1999, 2000, 2001, 2007, 2008 The NetBSD Foundation, Inc.
@@ -147,7 +147,7 @@
#include <sys/cdefs.h> /* RCS ID & Copyright macro defns */
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.232 2008/02/21 17:12:58 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.233 2008/03/10 13:36:22 ad Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -2998,9 +2998,6 @@ pmap_physpage_alloc(int usage, paddr_t *pap)
{
struct vm_page *pg;
paddr_t pa;
-#ifdef DEBUG
- kmutex_t *lock;
-#endif
/*
* Don't ask for a zero'd page in the L1PT case -- we will
@@ -3011,16 +3008,12 @@ pmap_physpage_alloc(int usage, paddr_t *pap)
UVM_PGA_USERESERVE : UVM_PGA_USERESERVE|UVM_PGA_ZERO);
if (pg != NULL) {
pa = VM_PAGE_TO_PHYS(pg);
-
#ifdef DEBUG
- lock = pmap_pvh_lock(pg);
- mutex_enter(lock);
- if (pg->wire_count != 0) {
+ if (pg->mdpage.pvh_refcnt != 0) {
printf("pmap_physpage_alloc: page 0x%lx has "
- "%d references\n", pa, pg->wire_count);
+ "%d references\n", pa, pg->mdpage.pvh_refcnt);
panic("pmap_physpage_alloc");
}
- mutex_exit(lock);
#endif
*pap = pa;
return (true);
@@ -3042,13 +3035,8 @@ pmap_physpage_free(paddr_t pa)
panic("pmap_physpage_free: bogus physical page address");
#ifdef DEBUG
- {
- kmutex_t *lock = pmap_pvh_lock(pg);
- mutex_enter(lock);
- if (pg->wire_count != 0)
- panic("pmap_physpage_free: page still has references");
- mutex_exit(lock);
- }
+ if (pg->mdpage.pvh_refcnt != 0)
+ panic("pmap_physpage_free: page still has references");
#endif
uvm_pagefree(pg);
@@ -3064,18 +3052,13 @@ pmap_physpage_addref(void *kva)
{
struct vm_page *pg;
paddr_t pa;
- int rval;
- kmutex_t *lock;
pa = ALPHA_K0SEG_TO_PHYS(trunc_page((vaddr_t)kva));
pg = PHYS_TO_VM_PAGE(pa);
- lock = pmap_pvh_lock(pg);
- mutex_enter(lock);
- rval = ++pg->wire_count;
- mutex_exit(lock);
+ KASSERT((int)pg->mdpage.pvh_refcnt >= 0);
- return (rval);
+ return atomic_inc_uint_nv(&pg->mdpage.pvh_refcnt);
}
/*
@@ -3088,28 +3071,13 @@ pmap_physpage_delref(void *kva)
{
struct vm_page *pg;
paddr_t pa;
- int rval;
- kmutex_t *lock;
pa = ALPHA_K0SEG_TO_PHYS(trunc_page((vaddr_t)kva));
pg = PHYS_TO_VM_PAGE(pa);
- lock = pmap_pvh_lock(pg);
- mutex_enter(lock);
-
-#ifdef DIAGNOSTIC
- /*
- * Make sure we never have a negative reference count.
- */
- if (pg->wire_count == 0)
- panic("pmap_physpage_delref: reference count already zero");
-#endif
-
- rval = --pg->wire_count;
-
- mutex_exit(lock);
+ KASSERT((int)pg->mdpage.pvh_refcnt > 0);
- return (rval);
+ return atomic_dec_uint_nv(&pg->mdpage.pvh_refcnt);
}
/******************** page table page management ********************/
diff --git a/sys/arch/alpha/include/vmparam.h b/sys/arch/alpha/include/vmparam.h
index 082c14f310d..7ad1996db77 100644
--- a/sys/arch/alpha/include/vmparam.h
+++ b/sys/arch/alpha/include/vmparam.h
@@ -1,4 +1,4 @@
-/* $NetBSD: vmparam.h,v 1.31 2008/02/21 17:12:58 ad Exp $ */
+/* $NetBSD: vmparam.h,v 1.32 2008/03/10 13:36:22 ad Exp $ */
/*
* Copyright (c) 1992, 1993
@@ -167,11 +167,13 @@
struct vm_page_md {
struct pv_entry *pvh_list; /* pv_entry list */
int pvh_attrs; /* page attributes */
+ unsigned pvh_refcnt;
};
#define VM_MDPAGE_INIT(pg) \
do { \
(pg)->mdpage.pvh_list = NULL; \
+ (pg)->mdpage.pvh_refcnt = 0; \
} while (/*CONSTCOND*/0)
#endif /* ! _ALPHA_VMPARAM_H_ */