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vm_map_madvise:

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A complete rewrite by dillon and myself to separate
	the implementation of behaviors that effect the vm_map_entry
	from those that effect the vm_object.

	A result of this change is that madvise(..., MADV_FREE);
	is much cheaper.
This commit is contained in:
alc 1999-08-13 17:45:34 +00:00
parent a9521339a7
commit 7fd2f69ac5
1 changed files with 88 additions and 63 deletions
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151
sys/vm/vm_map.c
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@ -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 1.174 1999/08/01 06:05:08 alc Exp $
* $Id: vm_map.c,v 1.175 1999/08/10 04:50:20 alc Exp $
*/
/*
@ -1005,88 +1005,113 @@ vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
* vm_map_madvise:
*
* This routine traverses a processes map handling the madvise
* system call.
* system call. Advisories are classified as either those effecting
* the vm_map_entry structure, or those effecting the underlying
* objects.
*/
void
vm_map_madvise(map, start, end, advise)
vm_map_madvise(map, start, end, behav)
vm_map_t map;
vm_offset_t start, end;
int advise;
int behav;
{
vm_map_entry_t current;
vm_map_entry_t entry;
vm_map_entry_t current, entry;
int modify_map;
vm_map_lock(map);
modify_map = (behav == MADV_NORMAL || behav == MADV_SEQUENTIAL ||
behav == MADV_RANDOM);
if (modify_map) {
vm_map_lock(map);
}
else
vm_map_lock_read(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (vm_map_lookup_entry(map, start, &entry)) {
vm_map_clip_start(map, entry, start);
if (modify_map)
vm_map_clip_start(map, entry, start);
} else
entry = entry->next;
for(current = entry;
(current != &map->header) && (current->start < end);
current = current->next) {
if (modify_map) {
/*
* madvise behaviors that are implemented in the vm_map_entry.
*
* We clip the vm_map_entry so that behavioral changes are
* limited to the specified address range.
*/
for (current = entry;
(current != &map->header) && (current->start < end);
current = current->next) {
if (current->eflags & MAP_ENTRY_IS_SUB_MAP) {
continue;
}
if (current->eflags & MAP_ENTRY_IS_SUB_MAP)
continue;
vm_map_clip_end(map, current, end);
vm_map_clip_end(map, current, end);
switch (advise) {
case MADV_NORMAL:
vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_NORMAL);
break;
case MADV_SEQUENTIAL:
vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_SEQUENTIAL);
break;
case MADV_RANDOM:
vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_RANDOM);
break;
/*
* Right now, we could handle DONTNEED and WILLNEED with common code.
* They are mostly the same, except for the potential async reads (NYI).
*/
case MADV_FREE:
case MADV_DONTNEED:
{
vm_pindex_t pindex;
int count;
pindex = OFF_TO_IDX(current->offset);
count = OFF_TO_IDX(current->end - current->start);
/*
* MADV_DONTNEED removes the page from all
* pmaps, so pmap_remove is not necessary.
*/
vm_object_madvise(current->object.vm_object,
pindex, count, advise);
switch (behav) {
case MADV_NORMAL:
vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_NORMAL);
break;
case MADV_SEQUENTIAL:
vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_SEQUENTIAL);
break;
case MADV_RANDOM:
vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_RANDOM);
break;
default:
break;
}
break;
case MADV_WILLNEED:
{
vm_pindex_t pindex;
int count;
pindex = OFF_TO_IDX(current->offset);
count = OFF_TO_IDX(current->end - current->start);
vm_object_madvise(current->object.vm_object,
pindex, count, advise);
pmap_object_init_pt(map->pmap, current->start,
current->object.vm_object, pindex,
(count << PAGE_SHIFT), 0);
}
break;
default:
break;
vm_map_simplify_entry(map, current);
}
vm_map_unlock(map);
}
else {
if (behav == MADV_FREE || behav == MADV_DONTNEED ||
behav == MADV_WILLNEED) {
vm_pindex_t pindex;
int count;
vm_map_simplify_entry(map, entry);
vm_map_unlock(map);
return;
/*
* madvise behaviors that are implemented in the underlying
* vm_object.
*
* Since we don't clip the vm_map_entry, we have to clip
* the vm_object pindex and count.
*/
for (current = entry;
(current != &map->header) && (current->start < end);
current = current->next) {
if (current->eflags & MAP_ENTRY_IS_SUB_MAP)
continue;
pindex = OFF_TO_IDX(current->offset);
count = atop(current->end - current->start);
if (current->start < start) {
pindex += atop(start - current->start);
count -= atop(start - current->start);
}
if (current->end > end)
count -= atop(current->end - end);
if (count <= 0)
continue;
vm_object_madvise(current->object.vm_object,
pindex, count, behav);
if (behav == MADV_WILLNEED)
pmap_object_init_pt(map->pmap, current->start,
current->object.vm_object,
pindex, (count << PAGE_SHIFT),
0);
}
}
vm_map_unlock_read(map);
}
}