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[src/trunk]: src/sys/arch/alpha Store the modified / referenced attribute bit...
details: https://anonhg.NetBSD.org/src/rev/608d00d08eda
branches: trunk
changeset: 1021431:608d00d08eda
user: thorpej <thorpej%NetBSD.org@localhost>
date: Sun May 30 06:41:19 2021 +0000
description:
Store the modified / referenced attribute bits in the lower 2 bits of
the PV entry list pointer in struct vm_page_md. This reduces the size
of that structure from 16 bytes to 8, and will go a fair way to making
up for increasing the size of struct pv_entry in a future commit.
diffstat:
sys/arch/alpha/alpha/pmap.c | 41 ++++++++++++++++++++++-------------------
sys/arch/alpha/include/pmap.h | 21 ++++++++++-----------
2 files changed, 32 insertions(+), 30 deletions(-)
diffs (177 lines):
diff -r 4ff66cddce9e -r 608d00d08eda sys/arch/alpha/alpha/pmap.c
--- a/sys/arch/alpha/alpha/pmap.c Sun May 30 06:05:24 2021 +0000
+++ b/sys/arch/alpha/alpha/pmap.c Sun May 30 06:41:19 2021 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.c,v 1.286 2021/05/30 05:26:09 thorpej Exp $ */
+/* $NetBSD: pmap.c,v 1.287 2021/05/30 06:41:19 thorpej Exp $ */
/*-
* Copyright (c) 1998, 1999, 2000, 2001, 2007, 2008, 2020
@@ -135,7 +135,7 @@
#include <sys/cdefs.h> /* RCS ID & Copyright macro defns */
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.286 2021/05/30 05:26:09 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.287 2021/05/30 06:41:19 thorpej Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -2233,17 +2233,18 @@
npte = ((pa >> PGSHIFT) << PG_SHIFT) | pte_prot(pmap, prot) | PG_V;
if (pg != NULL) {
struct vm_page_md * const md = VM_PAGE_TO_MD(pg);
- int attrs;
+ uintptr_t attrs = 0;
KASSERT(((flags & VM_PROT_ALL) & ~prot) == 0);
+ if (flags & VM_PROT_WRITE)
+ attrs |= (PGA_REFERENCED|PGA_MODIFIED);
+ else if (flags & VM_PROT_ALL)
+ attrs |= PGA_REFERENCED;
+
lock = pmap_pvh_lock(pg);
mutex_enter(lock);
- if (flags & VM_PROT_WRITE)
- md->pvh_attrs |= (PGA_REFERENCED|PGA_MODIFIED);
- else if (flags & VM_PROT_ALL)
- md->pvh_attrs |= PGA_REFERENCED;
- attrs = md->pvh_attrs;
+ md->pvh_listx |= attrs;
mutex_exit(lock);
/* Set up referenced/modified emulation for new mapping. */
@@ -2779,10 +2780,10 @@
lock = pmap_pvh_lock(pg);
mutex_enter(lock);
- if (md->pvh_attrs & PGA_MODIFIED) {
+ if (md->pvh_listx & PGA_MODIFIED) {
rv = true;
pmap_changebit(pg, PG_FOW, ~0UL, &tlbctx);
- md->pvh_attrs &= ~PGA_MODIFIED;
+ md->pvh_listx &= ~PGA_MODIFIED;
}
mutex_exit(lock);
@@ -2818,10 +2819,10 @@
lock = pmap_pvh_lock(pg);
mutex_enter(lock);
- if (md->pvh_attrs & PGA_REFERENCED) {
+ if (md->pvh_listx & PGA_REFERENCED) {
rv = true;
pmap_changebit(pg, PG_FOR | PG_FOW | PG_FOE, ~0UL, &tlbctx);
- md->pvh_attrs &= ~PGA_REFERENCED;
+ md->pvh_listx &= ~PGA_REFERENCED;
}
mutex_exit(lock);
@@ -3133,10 +3134,10 @@
mutex_enter(lock);
if (type == ALPHA_MMCSR_FOW) {
- md->pvh_attrs |= (PGA_REFERENCED|PGA_MODIFIED);
+ md->pvh_listx |= (PGA_REFERENCED|PGA_MODIFIED);
faultoff = PG_FOR | PG_FOW;
} else {
- md->pvh_attrs |= PGA_REFERENCED;
+ md->pvh_listx |= PGA_REFERENCED;
faultoff = PG_FOR;
if (exec) {
faultoff |= PG_FOE;
@@ -3173,7 +3174,7 @@
lock = pmap_pvh_lock(pg);
mutex_enter(lock);
- printf("pa 0x%lx (attrs = 0x%x):\n", pa, md->pvh_attrs);
+ printf("pa 0x%lx (attrs = 0x%x):\n", pa, md->pvh_listx & PGA_ATTRS);
for (pv = VM_MDPAGE_PVS(pg); pv != NULL; pv = pv->pv_next)
printf(" pmap %p, va 0x%lx\n",
pv->pv_pmap, pv->pv_va);
@@ -3274,8 +3275,9 @@
/*
* ...and put it in the list.
*/
- newpv->pv_next = md->pvh_list;
- md->pvh_list = newpv;
+ uintptr_t const attrs = md->pvh_listx & PGA_ATTRS;
+ newpv->pv_next = (struct pv_entry *)(md->pvh_listx & ~PGA_ATTRS);
+ md->pvh_listx = (uintptr_t)newpv | attrs;
if (dolock) {
mutex_exit(lock);
@@ -3307,14 +3309,15 @@
/*
* Find the entry to remove.
*/
- for (pvp = &md->pvh_list, pv = *pvp;
+ for (pvp = (struct pv_entry **)&md->pvh_listx, pv = VM_MDPAGE_PVS(pg);
pv != NULL; pvp = &pv->pv_next, pv = *pvp)
if (pmap == pv->pv_pmap && va == pv->pv_va)
break;
KASSERT(pv != NULL);
- *pvp = pv->pv_next;
+ *pvp = (pv_entry_t)((uintptr_t)pv->pv_next |
+ (((uintptr_t)*pvp) & PGA_ATTRS));
if (dolock) {
mutex_exit(lock);
diff -r 4ff66cddce9e -r 608d00d08eda sys/arch/alpha/include/pmap.h
--- a/sys/arch/alpha/include/pmap.h Sun May 30 06:05:24 2021 +0000
+++ b/sys/arch/alpha/include/pmap.h Sun May 30 06:41:19 2021 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.h,v 1.92 2021/05/30 05:26:09 thorpej Exp $ */
+/* $NetBSD: pmap.h,v 1.93 2021/05/30 06:41:19 thorpej Exp $ */
/*-
* Copyright (c) 1998, 1999, 2000, 2001, 2007 The NetBSD Foundation, Inc.
@@ -177,9 +177,10 @@
pt_entry_t *pv_pte; /* PTE that maps the VA */
} *pv_entry_t;
-/* pvh_attrs */
-#define PGA_MODIFIED 0x01 /* modified */
-#define PGA_REFERENCED 0x02 /* referenced */
+/* attrs in pvh_listx */
+#define PGA_MODIFIED 0x01UL /* modified */
+#define PGA_REFERENCED 0x02UL /* referenced */
+#define PGA_ATTRS (PGA_MODIFIED | PGA_REFERENCED)
/* pvh_usage */
#define PGU_NORMAL 0 /* free or normal use */
@@ -214,9 +215,9 @@
}
#define pmap_is_referenced(pg) \
- (((pg)->mdpage.pvh_attrs & PGA_REFERENCED) != 0)
+ (((pg)->mdpage.pvh_listx & PGA_REFERENCED) != 0)
#define pmap_is_modified(pg) \
- (((pg)->mdpage.pvh_attrs & PGA_MODIFIED) != 0)
+ (((pg)->mdpage.pvh_listx & PGA_MODIFIED) != 0)
#define PMAP_STEAL_MEMORY /* enable pmap_steal_memory() */
#define PMAP_GROWKERNEL /* enable pmap_growkernel() */
@@ -359,17 +360,15 @@
*/
#define __HAVE_VM_PAGE_MD
struct vm_page_md {
- struct pv_entry *pvh_list; /* pv_entry list */
- int pvh_attrs; /* page attributes */
+ uintptr_t pvh_listx; /* pv_entry list + attrs */
};
#define VM_MDPAGE_PVS(pg) \
- ((pg)->mdpage.pvh_list)
+ ((struct pv_entry *)((pg)->mdpage.pvh_listx & ~3UL))
#define VM_MDPAGE_INIT(pg) \
do { \
- (pg)->mdpage.pvh_list = NULL; \
- (pg)->mdpage.pvh_attrs = 0; \
+ (pg)->mdpage.pvh_listx = 0UL; \
} while (/*CONSTCOND*/0)
#endif /* _KERNEL */
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