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Use atomics to maintain the number of special page references. Should fix

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locking problems including in revision 1.232.
This commit is contained in:
ad 2008-03-10 13:36:22 +00:00
parent ee76f56f70
commit 8228d024b7
2 changed files with 13 additions and 43 deletions
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52
sys/arch/alpha/alpha/pmap.c
View File

@ -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);
KASSERT((int)pg->mdpage.pvh_refcnt > 0);
#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);
return (rval);
return atomic_dec_uint_nv(&pg->mdpage.pvh_refcnt);
}
/******************** page table page management ********************/

4
sys/arch/alpha/include/vmparam.h
View File

@ -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_ */