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Enhance pmap_change_attr() with the ability to demote 1GB page mappings.

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This commit is contained in:
Alan Cox 2008-08-01 04:55:38 +00:00
parent d4af9e693f
commit 67cbc11594
2 changed files with 106 additions and 2 deletions
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107
sys/amd64/amd64/pmap.c
View File

@ -222,6 +222,8 @@ static pv_entry_t pmap_pvh_remove(struct md_page *pvh, pmap_t pmap,
static int pmap_pvh_wired_mappings(struct md_page *pvh, int count);
static boolean_t pmap_demote_pde(pmap_t pmap, pd_entry_t *pde, vm_offset_t va);
static boolean_t pmap_demote_pdpe(pmap_t pmap, pdp_entry_t *pdpe,
vm_offset_t va);
static boolean_t pmap_enter_pde(pmap_t pmap, vm_offset_t va, vm_page_t m,
vm_prot_t prot);
static vm_page_t pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va,
@ -741,6 +743,13 @@ static u_long pmap_pde_promotions;
SYSCTL_ULONG(_vm_pmap_pde, OID_AUTO, promotions, CTLFLAG_RD,
&pmap_pde_promotions, 0, "2MB page promotions");
SYSCTL_NODE(_vm_pmap, OID_AUTO, pdpe, CTLFLAG_RD, 0,
"1GB page mapping counters");
static u_long pmap_pdpe_demotions;
SYSCTL_ULONG(_vm_pmap_pdpe, OID_AUTO, demotions, CTLFLAG_RD,
&pmap_pdpe_demotions, 0, "1GB page demotions");
/***************************************************
* Low level helper routines.....
@ -4349,6 +4358,60 @@ pmap_unmapdev(vm_offset_t va, vm_size_t size)
kmem_free(kernel_map, base, size);
}
/*
* Tries to demote a 1GB page mapping.
*/
static boolean_t
pmap_demote_pdpe(pmap_t pmap, pdp_entry_t *pdpe, vm_offset_t va)
{
pdp_entry_t newpdpe, oldpdpe;
pd_entry_t *firstpde, newpde, *pde;
vm_paddr_t mpdepa;
vm_page_t mpde;
PMAP_LOCK_ASSERT(pmap, MA_OWNED);
oldpdpe = *pdpe;
KASSERT((oldpdpe & (PG_PS | PG_V)) == (PG_PS | PG_V),
("pmap_demote_pdpe: oldpdpe is missing PG_PS and/or PG_V"));
if ((mpde = vm_page_alloc(NULL, va >> PDPSHIFT, VM_ALLOC_INTERRUPT |
VM_ALLOC_NOOBJ | VM_ALLOC_WIRED)) == NULL) {
CTR2(KTR_PMAP, "pmap_demote_pdpe: failure for va %#lx"
" in pmap %p", va, pmap);
return (FALSE);
}
mpdepa = VM_PAGE_TO_PHYS(mpde);
firstpde = (pd_entry_t *)PHYS_TO_DMAP(mpdepa);
newpdpe = mpdepa | PG_M | PG_A | (oldpdpe & PG_U) | PG_RW | PG_V;
KASSERT((oldpdpe & PG_A) != 0,
("pmap_demote_pdpe: oldpdpe is missing PG_A"));
KASSERT((oldpdpe & (PG_M | PG_RW)) != PG_RW,
("pmap_demote_pdpe: oldpdpe is missing PG_M"));
newpde = oldpdpe;
/*
* Initialize the page directory page.
*/
for (pde = firstpde; pde < firstpde + NPDEPG; pde++) {
*pde = newpde;
newpde += NBPDR;
}
/*
* Demote the mapping.
*/
*pdpe = newpdpe;
/*
* Invalidate a stale recursive mapping of the page directory page.
*/
pmap_invalidate_page(pmap, (vm_offset_t)vtopde(va));
pmap_pdpe_demotions++;
CTR2(KTR_PMAP, "pmap_demote_pdpe: success for va %#lx"
" in pmap %p", va, pmap);
return (TRUE);
}
int
pmap_change_attr(vm_offset_t va, vm_size_t size, int mode)
{
@ -4380,10 +4443,38 @@ pmap_change_attr(vm_offset_t va, vm_size_t size, int mode)
PMAP_LOCK(kernel_pmap);
for (tmpva = base; tmpva < base + size; ) {
pdpe = pmap_pdpe(kernel_pmap, tmpva);
if (*pdpe == 0 || (*pdpe & PG_PS)) {
if (*pdpe == 0) {
PMAP_UNLOCK(kernel_pmap);
return (EINVAL);
}
if (*pdpe & PG_PS) {
/*
* If the current 1GB page already has the required
* memory type, then we need not demote this page. Just
* increment tmpva to the next 1GB page frame.
*/
if (cache_bits_pde < 0)
cache_bits_pde = pmap_cache_bits(mode, 1);
if ((*pdpe & PG_PDE_CACHE) == cache_bits_pde) {
tmpva = trunc_1gpage(tmpva) + NBPDP;
continue;
}
/*
* If the current offset aligns with a 1GB page frame
* and there is at least 1GB left within the range, then
* we need not break down this page into 2MB pages.
*/
if ((tmpva & PDPMASK) == 0 &&
tmpva + PDPMASK < base + size) {
tmpva += NBPDP;
continue;
}
if (!pmap_demote_pdpe(kernel_pmap, pdpe, tmpva)) {
PMAP_UNLOCK(kernel_pmap);
return (ENOMEM);
}
}
pde = pmap_pdpe_to_pde(pdpe, tmpva);
if (*pde == 0) {
PMAP_UNLOCK(kernel_pmap);
@ -4431,7 +4522,19 @@ pmap_change_attr(vm_offset_t va, vm_size_t size, int mode)
* cache mode if required.
*/
for (tmpva = base; tmpva < base + size; ) {
pde = pmap_pde(kernel_pmap, tmpva);
pdpe = pmap_pdpe(kernel_pmap, tmpva);
if (*pdpe & PG_PS) {
if (cache_bits_pde < 0)
cache_bits_pde = pmap_cache_bits(mode, 1);
if ((*pdpe & PG_PDE_CACHE) != cache_bits_pde) {
pmap_pde_attr(pdpe, cache_bits_pde);
if (!changed)
changed = TRUE;
}
tmpva = trunc_1gpage(tmpva) + NBPDP;
continue;
}
pde = pmap_pdpe_to_pde(pdpe, tmpva);
if (*pde & PG_PS) {
if (cache_bits_pde < 0)
cache_bits_pde = pmap_cache_bits(mode, 1);

1
sys/amd64/include/param.h
View File

@ -146,6 +146,7 @@
#define trunc_page(x) ((unsigned long)(x) & ~(PAGE_MASK))
#define trunc_2mpage(x) ((unsigned long)(x) & ~PDRMASK)
#define round_2mpage(x) ((((unsigned long)(x)) + PDRMASK) & ~PDRMASK)
#define trunc_1gpage(x) ((unsigned long)(x) & ~PDPMASK)
#define atop(x) ((unsigned long)(x) >> PAGE_SHIFT)
#define ptoa(x) ((unsigned long)(x) << PAGE_SHIFT)