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MFC r203085

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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().
This commit is contained in:
Alan Cox 2010-02-21 04:10:25 +00:00
parent 69b0137459
commit 454947a618
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/stable/8/; revision=204162
1 changed files with 15 additions and 21 deletions
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34
sys/i386/i386/pmap.c
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@ -423,7 +423,6 @@ pmap_bootstrap(vm_paddr_t firstaddr)
}
SYSMAP(caddr_t, CMAP1, CADDR1, 1)
SYSMAP(caddr_t, CMAP3, CADDR3, 1)
*CMAP3 = 0;
/*
* Crashdump maps.
@ -446,7 +445,7 @@ 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
@ -458,15 +457,13 @@ 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
@ -539,25 +536,19 @@ pmap_init_pat(void)
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 {
@ -1885,7 +1876,7 @@ 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);
@ -2381,10 +2372,14 @@ pmap_demote_pde(pmap_t pmap, pd_entry_t *pde, vm_offset_t va)
mptepa = VM_PAGE_TO_PHYS(mpte);
/*
* Temporarily map the page table page (mpte) into the kernel's
* 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 (curthread->td_pinned > 0 && mtx_owned(&vm_page_queue_mtx)) {
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
@ -2448,10 +2443,9 @@ pmap_demote_pde(pmap_t pmap, pd_entry_t *pde, vm_offset_t va)
/*
* 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) {