A very significant improvement in the management of process maps
and objects. Previously, "fancy" memory management techniques such as that used by the M3 RTS would have the tendancy of chopping up processes allocated memory into lots of little objects. Alan has come up with some improvements to migtigate the sitution to the point where even the M3 RTS only has one object for bss and it's managed memory (when running CVSUP.) (There are still cases where the situation isn't improved when the system pages -- but this is much much better for the vast majority of cases.) The system will now be able to much more effectively merge map entries. Submitted by: Alan Cox <alc@cs.rice.edu>
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dyson
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@ -61,7 +61,7 @@
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*
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* $Id: vm_map.c,v 1.62 1996/12/14 17:54:15 dyson Exp $
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* $Id: vm_map.c,v 1.63 1996/12/28 23:07:48 dyson Exp $
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*/
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/*
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@ -583,7 +583,6 @@ vm_map_lookup_entry(map, address, entry)
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return (FALSE);
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}
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#define VM_MAP_INSERT_NULL_OBJECT_ONLY
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/*
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* vm_map_insert:
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*
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@ -638,46 +637,39 @@ vm_map_insert(map, object, offset, start, end, prot, max, cow)
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(prev_entry->next->start < end))
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return (KERN_NO_SPACE);
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if ((prev_entry != &map->header) &&
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(prev_entry->end == start) &&
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#if !defined(VM_MAP_INSERT_NULL_OBJECT_ONLY)
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((object == NULL) || (prev_entry->object.vm_object == object)) &&
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#else
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(object == NULL) &&
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#endif
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(prev_entry->is_a_map == FALSE) &&
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(prev_entry->is_sub_map == FALSE) &&
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(prev_entry->inheritance == VM_INHERIT_DEFAULT) &&
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(prev_entry->protection == prot) &&
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(prev_entry->max_protection == max) &&
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(prev_entry->wired_count == 0)) {
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/*
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* See if we can avoid creating a new entry by extending one of our
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* neighbors.
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* neighbors. Or at least extend the object.
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*/
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#if !defined(VM_MAP_INSERT_NULL_OBJECT_ONLY)
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if (object == NULL) {
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#endif
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u_char needs_copy = (cow & MAP_COPY_NEEDED) != 0;
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u_char copy_on_write = (cow & MAP_COPY_ON_WRITE) != 0;
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u_char nofault = (cow & MAP_NOFAULT) != 0;
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if ((needs_copy == prev_entry->needs_copy) &&
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(copy_on_write == prev_entry->copy_on_write) &&
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(nofault == prev_entry->nofault) &&
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(nofault || vm_object_coalesce(prev_entry->object.vm_object,
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OFF_TO_IDX(prev_entry->offset),
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(vm_size_t) (prev_entry->end
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- prev_entry->start),
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(vm_size_t) (end - prev_entry->end)))) {
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if ((object == NULL) &&
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(prev_entry != &map->header) &&
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( ! prev_entry->is_a_map) &&
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( ! prev_entry->is_sub_map) &&
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(prev_entry->end == start) &&
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(prev_entry->wired_count == 0)) {
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u_char needs_copy = (cow & MAP_COPY_NEEDED) != 0;
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u_char copy_on_write = (cow & MAP_COPY_ON_WRITE) != 0;
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u_char nofault = (cow & MAP_NOFAULT) != 0;
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if ((needs_copy == prev_entry->needs_copy) &&
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(copy_on_write == prev_entry->copy_on_write) &&
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(nofault == prev_entry->nofault) &&
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(nofault ||
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vm_object_coalesce(prev_entry->object.vm_object,
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OFF_TO_IDX(prev_entry->offset),
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(vm_size_t) (prev_entry->end - prev_entry->start),
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(vm_size_t) (end - prev_entry->end)))) {
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/*
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* Coalesced the two objects. Can we extend the
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* previous map entry to include the new range?
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*/
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if ((prev_entry->inheritance == VM_INHERIT_DEFAULT) &&
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(prev_entry->protection == prot) &&
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(prev_entry->max_protection == max)) {
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/*
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* Coalesced the two objects - can extend the
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* previous map entry to include the new
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* range.
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*/
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map->size += (end - prev_entry->end);
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prev_entry->end = end;
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if (!nofault) {
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@ -686,10 +678,16 @@ vm_map_insert(map, object, offset, start, end, prot, max, cow)
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}
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return (KERN_SUCCESS);
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}
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#if !defined(VM_MAP_INSERT_NULL_OBJECT_ONLY)
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else {
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object = prev_entry->object.vm_object;
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offset = prev_entry->offset + (prev_entry->end -
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prev_entry->start);
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vm_object_reference(object);
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}
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}
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#endif
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}
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/*
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* Create a new entry
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*/
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@ -61,7 +61,7 @@
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*
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* $Id: vm_object.c,v 1.81 1996/09/14 11:54:57 bde Exp $
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* $Id: vm_object.c,v 1.82 1996/09/28 03:33:26 dyson Exp $
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*/
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/*
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@ -1299,13 +1299,18 @@ vm_object_coalesce(prev_object, prev_pindex, prev_size, next_size)
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* pages not mapped to prev_entry may be in use anyway)
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*/
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if (prev_object->ref_count > 1 ||
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prev_object->backing_object != NULL) {
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if (prev_object->backing_object != NULL) {
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return (FALSE);
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}
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prev_size >>= PAGE_SHIFT;
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next_size >>= PAGE_SHIFT;
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if ((prev_object->ref_count > 1) &&
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(prev_object->size != prev_pindex + prev_size)) {
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return (FALSE);
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}
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/*
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* Remove any pages that may still be in the object from a previous
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* deallocation.
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