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Disable madvise optimizations for device pager objects (some of the

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operations don't work with FICTITIOUS pages.)  Also, close a window
between PG_MANAGED and pmap_enter that can mess up the accounting of
the managed flag.  This problem could likely cause a hold_count error
for page table pages.
This commit is contained in:
John Dyson 1996-06-01 20:50:57 +00:00
parent c2b39c9910
commit ff97964a2e
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=16058
1 changed files with 9 additions and 6 deletions
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15
sys/vm/vm_fault.c
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@ -66,7 +66,7 @@
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $Id: vm_fault.c,v 1.46 1996/05/26 05:30:33 dyson Exp $
* $Id: vm_fault.c,v 1.47 1996/05/31 00:37:56 dyson Exp $
*/
/*
@ -335,7 +335,8 @@ RetryFault:;
behind = 0;
}
if (first_object->behavior == OBJ_SEQUENTIAL) {
if ((first_object->type != OBJT_DEVICE) &&
(first_object->behavior == OBJ_SEQUENTIAL)) {
vm_pindex_t firstpindex, tmppindex;
if (first_pindex <
2*(VM_FAULT_READ_BEHIND + VM_FAULT_READ_AHEAD + 1))
@ -351,7 +352,9 @@ RetryFault:;
mt = vm_page_lookup( first_object, tmppindex);
if (mt == NULL || (mt->valid != VM_PAGE_BITS_ALL))
break;
if (mt->busy || (mt->flags & PG_BUSY) || mt->hold_count ||
if (mt->busy ||
(mt->flags & (PG_BUSY|PG_FICTITIOUS)) ||
mt->hold_count ||
mt->wire_count)
continue;
if (mt->dirty == 0)
@ -748,15 +751,15 @@ RetryFault:;
}
UNLOCK_THINGS;
m->flags |= PG_MAPPED|PG_REFERENCED;
m->flags &= ~PG_ZERO;
m->valid = VM_PAGE_BITS_ALL;
m->flags &= ~PG_ZERO;
pmap_enter(map->pmap, vaddr, VM_PAGE_TO_PHYS(m), prot, wired);
if ((change_wiring == 0) && (wired == 0))
pmap_prefault(map->pmap, vaddr, entry, first_object);
m->flags |= PG_MAPPED|PG_REFERENCED;
/*
* If the page is not wired down, then put it where the pageout daemon
* can find it.