Author: alc
Date: Thu Sep 19 20:45:23 2019
New Revision: 352541
URL: https://svnweb.freebsd.org/changeset/base/352541
Log:
MF r349585
Tidy up pmap_copy(). Notably, deindent the innermost loop by making a
simple change to the control flow. Replace an unnecessary test by a
KASSERT. Add a comment explaining an obscure test.
Modified:
stable/12/sys/amd64/amd64/pmap.c
Directory Properties:
stable/12/ (props changed)
Modified: stable/12/sys/amd64/amd64/pmap.c
==============================================================================
--- stable/12/sys/amd64/amd64/pmap.c Thu Sep 19 20:16:51 2019
(r352540)
+++ stable/12/sys/amd64/amd64/pmap.c Thu Sep 19 20:45:23 2019
(r352541)
@@ -6355,18 +6355,18 @@ pmap_unwire(pmap_t pmap, vm_offset_t sva, vm_offset_t
*
* This routine is only advisory and need not do anything.
*/
-
void
pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vm_offset_t dst_addr, vm_size_t
len,
vm_offset_t src_addr)
{
struct rwlock *lock;
struct spglist free;
- vm_offset_t addr;
- vm_offset_t end_addr = src_addr + len;
- vm_offset_t va_next;
+ pml4_entry_t *pml4e;
+ pdp_entry_t *pdpe;
+ pd_entry_t *pde, srcptepaddr;
+ pt_entry_t *dst_pte, PG_A, PG_M, PG_V, ptetemp, *src_pte;
+ vm_offset_t addr, end_addr, va_next;
vm_page_t dst_pdpg, dstmpte, srcmpte;
- pt_entry_t PG_A, PG_M, PG_V;
if (dst_addr != src_addr)
return;
@@ -6385,6 +6385,7 @@ pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vm_offset_
if (pmap_emulate_ad_bits(dst_pmap))
return;
+ end_addr = src_addr + len;
lock = NULL;
if (dst_pmap < src_pmap) {
PMAP_LOCK(dst_pmap);
@@ -6399,11 +6400,6 @@ pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vm_offset_
PG_V = pmap_valid_bit(dst_pmap);
for (addr = src_addr; addr < end_addr; addr = va_next) {
- pt_entry_t *src_pte, *dst_pte;
- pml4_entry_t *pml4e;
- pdp_entry_t *pdpe;
- pd_entry_t srcptepaddr, *pde;
-
KASSERT(addr < UPT_MIN_ADDRESS,
("pmap_copy: invalid to pmap_copy page tables"));
@@ -6445,7 +6441,8 @@ pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vm_offset_
pmap_pv_insert_pde(dst_pmap, addr, srcptepaddr,
PMAP_ENTER_NORECLAIM, &lock))) {
*pde = srcptepaddr & ~PG_W;
- pmap_resident_count_inc(dst_pmap, NBPDR /
PAGE_SIZE);
+ pmap_resident_count_inc(dst_pmap, NBPDR /
+ PAGE_SIZE);
atomic_add_long(&pmap_pde_mappings, 1);
} else
dst_pdpg->wire_count--;
@@ -6463,58 +6460,54 @@ pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vm_offset_
src_pte = (pt_entry_t *)PHYS_TO_DMAP(srcptepaddr);
src_pte = &src_pte[pmap_pte_index(addr)];
dstmpte = NULL;
- while (addr < va_next) {
- pt_entry_t ptetemp;
+ for (; addr < va_next; addr += PAGE_SIZE, src_pte++) {
ptetemp = *src_pte;
+
/*
- * we only virtual copy managed pages
+ * We only virtual copy managed pages.
*/
- if ((ptetemp & PG_MANAGED) != 0) {
- if (dstmpte != NULL &&
- dstmpte->pindex == pmap_pde_pindex(addr))
- dstmpte->wire_count++;
- else if ((dstmpte = pmap_allocpte(dst_pmap,
- addr, NULL)) == NULL)
- goto out;
- dst_pte = (pt_entry_t *)
- PHYS_TO_DMAP(VM_PAGE_TO_PHYS(dstmpte));
- dst_pte = &dst_pte[pmap_pte_index(addr)];
- if (*dst_pte == 0 &&
- pmap_try_insert_pv_entry(dst_pmap, addr,
- PHYS_TO_VM_PAGE(ptetemp & PG_FRAME),
- &lock)) {
+ if ((ptetemp & PG_MANAGED) == 0)
+ continue;
+
+ if (dstmpte != NULL) {
+ KASSERT(dstmpte->pindex ==
+ pmap_pde_pindex(addr),
+ ("dstmpte pindex/addr mismatch"));
+ dstmpte->wire_count++;
+ } else if ((dstmpte = pmap_allocpte(dst_pmap, addr,
+ NULL)) == NULL)
+ goto out;
+ dst_pte = (pt_entry_t *)
+ PHYS_TO_DMAP(VM_PAGE_TO_PHYS(dstmpte));
+ dst_pte = &dst_pte[pmap_pte_index(addr)];
+ if (*dst_pte == 0 &&
+ pmap_try_insert_pv_entry(dst_pmap, addr,
+ PHYS_TO_VM_PAGE(ptetemp & PG_FRAME), &lock)) {
+ /*
+ * Clear the wired, modified, and accessed
+ * (referenced) bits during the copy.
+ */
+ *dst_pte = ptetemp & ~(PG_W | PG_M | PG_A);
+ pmap_resident_count_inc(dst_pmap, 1);
+ } else {
+ SLIST_INIT(&free);
+ if (pmap_unwire_ptp(dst_pmap, addr, dstmpte,
+ &free)) {
/*
- * Clear the wired, modified, and
- * accessed (referenced) bits
- * during the copy.
+ * Although "addr" is not mapped,
+ * paging-structure caches could
+ * nonetheless have entries that refer
+ * to the freed page table pages.
+ * Invalidate those entries.
*/
- *dst_pte = ptetemp & ~(PG_W | PG_M |
- PG_A);
- pmap_resident_count_inc(dst_pmap, 1);
- } else {
- SLIST_INIT(&free);
- if (pmap_unwire_ptp(dst_pmap, addr,
- dstmpte, &free)) {
- /*
- * Although "addr" is not
- * mapped, paging-structure
- * caches could nonetheless
- * have entries that refer to
- * the freed page table pages.
- * Invalidate those entries.
- */
- pmap_invalidate_page(dst_pmap,
- addr);
- vm_page_free_pages_toq(&free,
- true);
- }
- goto out;
+ pmap_invalidate_page(dst_pmap, addr);
+ vm_page_free_pages_toq(&free, true);
}
- if (dstmpte->wire_count >= srcmpte->wire_count)
- break;
+ goto out;
}
- addr += PAGE_SIZE;
- src_pte++;
+ /* Have we copied all of the valid mappings? */
+ if (dstmpte->wire_count >= srcmpte->wire_count)
+ break;
}
}
out:
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