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Eliminate the last use of the recursive mapping to access user-space page

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table pages.  Now, all accesses to user-space page table pages are
performed through the direct map.  (The recursive mapping is only used
to access kernel-space page table pages.)

Eliminate the TLB invalidation on the recursive mapping when a user-space
page table page is removed from the page table and when a user-space
superpage is demoted.
This commit is contained in:
Alan Cox 2009-03-10 02:12:03 +00:00
parent 215c1391c4
commit 280db2a6f5
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=189610
1 changed files with 12 additions and 27 deletions
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39
sys/amd64/amd64/pmap.c
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@ -1278,7 +1278,6 @@ static int
_pmap_unwire_pte_hold(pmap_t pmap, vm_offset_t va, vm_page_t m,
vm_page_t *free)
{
vm_offset_t pteva;
/*
* unmap the page table page
@ -1287,19 +1286,16 @@ _pmap_unwire_pte_hold(pmap_t pmap, vm_offset_t va, vm_page_t m,
/* PDP page */
pml4_entry_t *pml4;
pml4 = pmap_pml4e(pmap, va);
pteva = (vm_offset_t) PDPmap + amd64_ptob(m->pindex - (NUPDE + NUPDPE));
*pml4 = 0;
} else if (m->pindex >= NUPDE) {
/* PD page */
pdp_entry_t *pdp;
pdp = pmap_pdpe(pmap, va);
pteva = (vm_offset_t) PDmap + amd64_ptob(m->pindex - NUPDE);
*pdp = 0;
} else {
/* PTE page */
pd_entry_t *pd;
pd = pmap_pde(pmap, va);
pteva = (vm_offset_t) PTmap + amd64_ptob(m->pindex);
*pd = 0;
}
--pmap->pm_stats.resident_count;
@ -1325,12 +1321,6 @@ _pmap_unwire_pte_hold(pmap_t pmap, vm_offset_t va, vm_page_t m,
*/
atomic_subtract_rel_int(&cnt.v_wire_count, 1);
/*
* Do an invltlb to make the invalidated mapping
* take effect immediately.
*/
pmap_invalidate_page(pmap, pteva);
/*
* Put page on a list so that it is released after
* *ALL* TLB shootdown is done
@ -2277,9 +2267,10 @@ pmap_demote_pde(pmap_t pmap, pd_entry_t *pde, vm_offset_t va)
pde_store(pde, newpde);
/*
* Invalidate a stale mapping of the page table page.
* Invalidate a stale recursive mapping of the page table page.
*/
pmap_invalidate_page(pmap, (vm_offset_t)vtopte(va));
if (va >= VM_MAXUSER_ADDRESS)
pmap_invalidate_page(pmap, (vm_offset_t)vtopte(va));
/*
* Demote the pv entry. This depends on the earlier demotion
@ -3762,7 +3753,7 @@ pmap_page_is_mapped(vm_page_t m)
void
pmap_remove_pages(pmap_t pmap)
{
pd_entry_t *pde;
pd_entry_t ptepde;
pt_entry_t *pte, tpte;
vm_page_t free = NULL;
vm_page_t m, mpte, mt;
@ -3791,23 +3782,19 @@ pmap_remove_pages(pmap_t pmap)
pv = &pc->pc_pventry[idx];
inuse &= ~bitmask;
pde = vtopde(pv->pv_va);
tpte = *pde;
if ((tpte & PG_PS) != 0)
pte = pde;
else {
pte = pmap_pdpe(pmap, pv->pv_va);
ptepde = *pte;
pte = pmap_pdpe_to_pde(pte, pv->pv_va);
tpte = *pte;
if ((tpte & (PG_PS | PG_V)) == PG_V) {
ptepde = tpte;
pte = (pt_entry_t *)PHYS_TO_DMAP(tpte &
PG_FRAME);
pte = &pte[pmap_pte_index(pv->pv_va)];
tpte = *pte & ~PG_PTE_PAT;
}
if (tpte == 0) {
printf(
"TPTE at %p IS ZERO @ VA %08lx\n",
pte, pv->pv_va);
if ((tpte & PG_V) == 0)
panic("bad pte");
}
/*
* We cannot remove wired pages from a process' mapping at this time
@ -3863,8 +3850,6 @@ pmap_remove_pages(pmap_t pmap)
pmap_add_delayed_free_list(mpte, &free, FALSE);
atomic_subtract_int(&cnt.v_wire_count, 1);
}
pmap_unuse_pt(pmap, pv->pv_va,
*pmap_pdpe(pmap, pv->pv_va), &free);
} else {
pmap->pm_stats.resident_count--;
TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
@ -3873,8 +3858,8 @@ pmap_remove_pages(pmap_t pmap)
if (TAILQ_EMPTY(&pvh->pv_list))
vm_page_flag_clear(m, PG_WRITEABLE);
}
pmap_unuse_pt(pmap, pv->pv_va, *pde, &free);
}
pmap_unuse_pt(pmap, pv->pv_va, ptepde, &free);
}
}
if (allfree) {