mirror of
https://git.FreeBSD.org/src.git
synced 2025-01-12 14:29:28 +00:00
Fix non-fatal bug in vm_map_insert() which improperly cleared
OBJ_ONEMAPPING in the case where an object is extended by an
additional vm_map_entry must be allocated.
In vm_object_madvise(), remove calll to vm_page_cache() in MADV_FREE
case in order to avoid a page fault on page reuse. However, we still
mark the page as clean and destroy any swap backing store.
Submitted by: Alan Cox <alc@cs.rice.edu>
This commit is contained in:
Matthew Dillon
parent
28791bce44
commit
2aaeadf8d9
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=43923
@ -61,7 +61,7 @@
|
||||
* any improvements or extensions that they make and grant Carnegie the
|
||||
* rights to redistribute these changes.
|
||||
*
|
||||
* $Id: vm_map.c,v 1.147 1999/02/03 01:57:16 dillon Exp $
|
||||
* $Id: vm_map.c,v 1.148 1999/02/07 21:48:22 dillon Exp $
|
||||
*/
|
||||
|
||||
/*
|
||||
@ -429,6 +429,9 @@ vm_map_lookup_entry(map, address, entry)
|
||||
* size should match that of the address range.
|
||||
*
|
||||
* Requires that the map be locked, and leaves it so.
|
||||
*
|
||||
* If object is non-NULL, ref count must be bumped by caller
|
||||
* prior to making call to account for the new entry.
|
||||
*/
|
||||
int
|
||||
vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
|
||||
@ -438,9 +441,6 @@ vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
|
||||
vm_map_entry_t new_entry;
|
||||
vm_map_entry_t prev_entry;
|
||||
vm_map_entry_t temp_entry;
|
||||
#if 0
|
||||
vm_object_t prev_object;
|
||||
#endif
|
||||
u_char protoeflags;
|
||||
|
||||
if ((object != NULL) && (cow & MAP_NOFAULT)) {
|
||||
@ -483,13 +483,18 @@ vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
|
||||
if (cow & MAP_NOFAULT)
|
||||
protoeflags |= MAP_ENTRY_NOFAULT;
|
||||
|
||||
/*
|
||||
* See if we can avoid creating a new entry by extending one of our
|
||||
* neighbors. Or at least extend the object.
|
||||
*/
|
||||
|
||||
if (
|
||||
(object == NULL) &&
|
||||
if (object) {
|
||||
/*
|
||||
* When object is non-NULL, it could be shared with another
|
||||
* process. We have to set or clear OBJ_ONEMAPPING
|
||||
* appropriately.
|
||||
*/
|
||||
if ((object->ref_count > 1) || (object->shadow_count != 0)) {
|
||||
vm_object_clear_flag(object, OBJ_ONEMAPPING);
|
||||
} else {
|
||||
vm_object_set_flag(object, OBJ_ONEMAPPING);
|
||||
}
|
||||
} else if (
|
||||
(prev_entry != &map->header) &&
|
||||
((prev_entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) &&
|
||||
((prev_entry->object.vm_object == NULL) ||
|
||||
@ -506,8 +511,9 @@ vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
|
||||
(vm_size_t) (end - prev_entry->end)))) {
|
||||
|
||||
/*
|
||||
* Coalesced the two objects. Can we extend the
|
||||
* previous map entry to include the new range?
|
||||
* We were able to extend the object. Determine if we
|
||||
* can extend the previous map entry to include the
|
||||
* new range as well.
|
||||
*/
|
||||
if ((prev_entry->inheritance == VM_INHERIT_DEFAULT) &&
|
||||
(prev_entry->protection == prot) &&
|
||||
@ -515,27 +521,28 @@ vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
|
||||
|
||||
map->size += (end - prev_entry->end);
|
||||
prev_entry->end = end;
|
||||
#if 0
|
||||
/*
|
||||
* (no longer applies)
|
||||
*/
|
||||
if ((cow & MAP_NOFAULT) == 0) {
|
||||
prev_object = prev_entry->object.vm_object;
|
||||
default_pager_convert_to_swapq(prev_object);
|
||||
}
|
||||
#endif
|
||||
return (KERN_SUCCESS);
|
||||
}
|
||||
else {
|
||||
object = prev_entry->object.vm_object;
|
||||
offset = prev_entry->offset + (prev_entry->end -
|
||||
prev_entry->start);
|
||||
|
||||
vm_object_reference(object);
|
||||
}
|
||||
/*
|
||||
* If we can extend the object but cannot extend the
|
||||
* map entry, we have to create a new map entry. We
|
||||
* must bump the ref count on the extended object to
|
||||
* account for it.
|
||||
*/
|
||||
object = prev_entry->object.vm_object;
|
||||
offset = prev_entry->offset +
|
||||
(prev_entry->end - prev_entry->start);
|
||||
vm_object_reference(object);
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* NOTE: if conditionals fail, object can be NULL here. This occurs
|
||||
* in things like the buffer map where we manage kva but do not manage
|
||||
* backing objects.
|
||||
*/
|
||||
|
||||
/*
|
||||
* Create a new entry
|
||||
*/
|
||||
@ -549,14 +556,6 @@ vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
|
||||
new_entry->offset = offset;
|
||||
new_entry->avail_ssize = 0;
|
||||
|
||||
if (object) {
|
||||
if ((object->ref_count > 1) || (object->shadow_count != 0)) {
|
||||
vm_object_clear_flag(object, OBJ_ONEMAPPING);
|
||||
} else {
|
||||
vm_object_set_flag(object, OBJ_ONEMAPPING);
|
||||
}
|
||||
}
|
||||
|
||||
if (map->is_main_map) {
|
||||
new_entry->inheritance = VM_INHERIT_DEFAULT;
|
||||
new_entry->protection = prot;
|
||||
@ -577,12 +576,6 @@ vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
|
||||
(prev_entry->end >= new_entry->start))
|
||||
map->first_free = new_entry;
|
||||
|
||||
#if 0
|
||||
/*
|
||||
* (no longer applies)
|
||||
*/
|
||||
default_pager_convert_to_swapq(object);
|
||||
#endif
|
||||
return (KERN_SUCCESS);
|
||||
}
|
||||
|
||||
@ -853,6 +846,8 @@ vm_map_findspace(map, start, length, addr)
|
||||
* first-fit from the specified address; the region found is
|
||||
* returned in the same parameter.
|
||||
*
|
||||
* If object is non-NULL, ref count must be bumped by caller
|
||||
* prior to making call to account for the new entry.
|
||||
*/
|
||||
int
|
||||
vm_map_find(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
|
||||
|
||||
@ -61,7 +61,7 @@
|
||||
* any improvements or extensions that they make and grant Carnegie the
|
||||
* rights to redistribute these changes.
|
||||
*
|
||||
* $Id: vm_object.c,v 1.147 1999/02/08 05:15:54 dillon Exp $
|
||||
* $Id: vm_object.c,v 1.148 1999/02/08 19:00:15 dillon Exp $
|
||||
*/
|
||||
|
||||
/*
|
||||
@ -762,8 +762,8 @@ vm_object_madvise(object, pindex, count, advise)
|
||||
end = pindex + count;
|
||||
|
||||
/*
|
||||
* MADV_FREE special case - free any swap backing store (as well
|
||||
* as resident pages later on).
|
||||
* MADV_FREE special case - free any swap backing store now,
|
||||
* whether or not resident pages can be found later.
|
||||
*/
|
||||
|
||||
if (advise == MADV_FREE) {
|
||||
@ -835,24 +835,18 @@ vm_object_madvise(object, pindex, count, advise)
|
||||
vm_page_deactivate(m);
|
||||
} else if (advise == MADV_FREE) {
|
||||
/*
|
||||
* If MADV_FREE_FORCE_FREE is defined, we attempt to
|
||||
* immediately free the page. Otherwise we just
|
||||
* destroy any swap backing store, mark it clean,
|
||||
* and stuff it into the cache.
|
||||
* Mark the page clean. This will allow the page
|
||||
* to be freed up by the system. However, such pages
|
||||
* are often reused quickly by malloc()/free()
|
||||
* so we do not do anything that would cause
|
||||
* a page fault if we can help it.
|
||||
*
|
||||
* Specifically, we do not try to actually free
|
||||
* the page now nor do we try to put it in the
|
||||
* cache (which would cause a page fault on reuse).
|
||||
*/
|
||||
pmap_clear_modify(VM_PAGE_TO_PHYS(m));
|
||||
m->dirty = 0;
|
||||
|
||||
#ifdef MADV_FREE_FORCE_FREE
|
||||
if (tobject->resident_page_count > 1) {
|
||||
vm_page_busy(m);
|
||||
vm_page_protect(m, VM_PROT_NONE);
|
||||
vm_page_free(m);
|
||||
} else
|
||||
#endif
|
||||
{
|
||||
vm_page_cache(m);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user