Author: alc
Date: Wed Jan 27 18:33:22 2010
New Revision: 203085
URL: http://svn.freebsd.org/changeset/base/203085
Log:
Optimize pmap_demote_pde() by using the new KPTmap to access a kernel
page table page instead of creating a temporary mapping to it.
Set the PG_G bit on the page table entries that implement the KPTmap.
Locore initializes the unused portions of the NKPT kernel page table
pages that it allocates to zero. So, pmap_bootstrap() needn't zero
the page table entries referenced by CMAP1 and CMAP3.
Simplify pmap_set_pg().
MFC after: 10 days
Modified:
head/sys/i386/i386/pmap.c
Modified: head/sys/i386/i386/pmap.c
==============================================================================
--- head/sys/i386/i386/pmap.c Wed Jan 27 18:12:22 2010 (r203084)
+++ head/sys/i386/i386/pmap.c Wed Jan 27 18:33:22 2010 (r203085)
@@ -404,7 +404,6 @@ pmap_bootstrap(vm_paddr_t firstaddr)
}
SYSMAP(caddr_t, CMAP1, CADDR1, 1)
SYSMAP(caddr_t, CMAP3, CADDR3, 1)
- *CMAP3 = 0;
/*
* Crashdump maps.
@@ -427,7 +426,7 @@ pmap_bootstrap(vm_paddr_t firstaddr)
SYSMAP(pt_entry_t *, KPTD, KPTmap, KVA_PAGES)
for (i = 0; i < NKPT; i++)
- KPTD[i] = (KPTphys + (i << PAGE_SHIFT)) | PG_RW | PG_V;
+ KPTD[i] = (KPTphys + (i << PAGE_SHIFT)) | pgeflag | PG_RW |
PG_V;
/*
* Adjust the start of the KPTD and KPTmap so that the implementation
@@ -439,15 +438,13 @@ pmap_bootstrap(vm_paddr_t firstaddr)
/*
* ptemap is used for pmap_pte_quick
*/
- SYSMAP(pt_entry_t *, PMAP1, PADDR1, 1);
- SYSMAP(pt_entry_t *, PMAP2, PADDR2, 1);
+ SYSMAP(pt_entry_t *, PMAP1, PADDR1, 1)
+ SYSMAP(pt_entry_t *, PMAP2, PADDR2, 1)
mtx_init(&PMAP2mutex, "PMAP2", NULL, MTX_DEF);
virtual_avail = va;
- *CMAP1 = 0;
-
/*
* Leave in place an identity mapping (virt == phys) for the low 1 MB
* physical memory region that is used by the ACPI wakeup code. This
@@ -549,25 +546,19 @@ pmap_init_pat(void)
static void
pmap_set_pg(void)
{
- pd_entry_t pdir;
pt_entry_t *pte;
vm_offset_t va, endva;
- int i;
if (pgeflag == 0)
return;
- i = KERNLOAD/NBPDR;
endva = KERNBASE + KERNend;
if (pseflag) {
va = KERNBASE + KERNLOAD;
while (va < endva) {
- pdir = kernel_pmap->pm_pdir[KPTDI+i];
- pdir |= pgeflag;
- kernel_pmap->pm_pdir[KPTDI+i] = PTD[KPTDI+i] = pdir;
+ pdir_pde(PTD, va) |= pgeflag;
invltlb(); /* Play it safe, invltlb() every time */
- i++;
va += NBPDR;
}
} else {
@@ -1895,7 +1886,7 @@ pmap_growkernel(vm_offset_t addr)
pmap_zero_page(nkpg);
ptppaddr = VM_PAGE_TO_PHYS(nkpg);
newpdir = (pd_entry_t) (ptppaddr | PG_V | PG_RW | PG_A | PG_M);
- pdir_pde(KPTD, kernel_vm_end) = newpdir;
+ pdir_pde(KPTD, kernel_vm_end) = pgeflag | newpdir;
updated_PTD = FALSE;
mtx_lock_spin(&allpmaps_lock);
@@ -2391,10 +2382,14 @@ pmap_demote_pde(pmap_t pmap, pd_entry_t
mptepa = VM_PAGE_TO_PHYS(mpte);
/*
- * Temporarily map the page table page (mpte) into the kernel's
- * address space at either PADDR1 or PADDR2.
- */
- if (curthread->td_pinned > 0 && mtx_owned(&vm_page_queue_mtx)) {
+ * If the page mapping is in the kernel's address space, then the
+ * KPTmap can provide access to the page table page. Otherwise,
+ * temporarily map the page table page (mpte) into the kernel's
+ * address space at either PADDR1 or PADDR2.
+ */
+ if (va >= KERNBASE)
+ firstpte = &KPTmap[i386_btop(trunc_4mpage(va))];
+ else if (curthread->td_pinned > 0 && mtx_owned(&vm_page_queue_mtx)) {
if ((*PMAP1 & PG_FRAME) != mptepa) {
*PMAP1 = mptepa | PG_RW | PG_V | PG_A | PG_M;
#ifdef SMP
@@ -2458,10 +2453,9 @@ pmap_demote_pde(pmap_t pmap, pd_entry_t
/*
* A harmless race exists between this loop and the bcopy()
* in pmap_pinit() that initializes the kernel segment of
- * the new page table. Specifically, that bcopy() may copy
- * the new PDE from the PTD, which is first in allpmaps, to
- * the new page table before this loop updates that new
- * page table.
+ * the new page table directory. Specifically, that bcopy()
+ * may copy the new PDE from the PTD to the new page table
+ * before this loop updates that new page table.
*/
mtx_lock_spin(&allpmaps_lock);
LIST_FOREACH(allpmaps_entry, &allpmaps, pm_list) {
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