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o Add vm_map_unwire() for unwiring contiguous regions of either kernel

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or user vm_maps.  In accordance with the standards for munlock(2),
   and in contrast to vm_map_user_pageable(), this implementation does not
   allow holes in the specified region.  This implementation uses the
   "in transition" flag described below.
 o Introduce a new flag, "in transition," to the vm_map_entry.
   Eventually, vm_map_delete() and vm_map_simplify_entry() will respect
   this flag by deallocating in-transition vm_map_entrys, allowing
   the vm_map lock to be safely released in vm_map_unwire() and (the
   forthcoming) vm_map_wire().
 o Modify vm_map_simplify_entry() to respect the in-transition flag.

In collaboration with:	tegge
This commit is contained in:
Alan Cox 2002-06-07 18:34:23 +00:00
parent 82684fa6da
commit acd9a301ec
2 changed files with 167 additions and 1 deletions
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164
sys/vm/vm_map.c
View File

@ -423,6 +423,29 @@ _vm_map_clear_recursive(vm_map_t map, const char *file, int line)
{
}
/*
* vm_map_unlock_and_wait:
*/
static __inline int
vm_map_unlock_and_wait(vm_map_t map, boolean_t user_wait)
{
GIANT_REQUIRED;
vm_map_unlock(map);
return (tsleep(&map->root, PVM, "vmmapw", 0));
}
/*
* vm_map_wakeup:
*/
static __inline void
vm_map_wakeup(vm_map_t map)
{
wakeup(&map->root);
}
long
vmspace_resident_count(struct vmspace *vmspace)
{
@ -958,7 +981,7 @@ vm_map_simplify_entry(vm_map_t map, vm_map_entry_t entry)
vm_map_entry_t next, prev;
vm_size_t prevsize, esize;
if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
if (entry->eflags & (MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_IS_SUB_MAP))
return;
prev = entry->prev;
@ -1460,6 +1483,145 @@ vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end,
return (KERN_SUCCESS);
}
/*
* vm_map_unwire:
*
* Implements both kernel and user unwire.
*/
int
vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
boolean_t user_unwire)
{
vm_map_entry_t entry, first_entry, tmp_entry;
vm_offset_t saved_start;
unsigned int last_timestamp;
int rv;
boolean_t need_wakeup, result;
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (!vm_map_lookup_entry(map, start, &first_entry)) {
vm_map_unlock(map);
return (KERN_INVALID_ADDRESS);
}
last_timestamp = map->timestamp;
need_wakeup = FALSE;
entry = first_entry;
while (entry != &map->header && entry->start < end) {
if (entry->eflags & MAP_ENTRY_IN_TRANSITION) {
/*
* We have not yet clipped the entry.
*/
saved_start = (start >= entry->start) ? start :
entry->start;
entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
if (need_wakeup) {
vm_map_wakeup(map);
need_wakeup = FALSE;
}
if (vm_map_unlock_and_wait(map, user_unwire)) {
/*
* Allow interruption of user unwiring?
*/
}
vm_map_lock(map);
if (last_timestamp+1 != map->timestamp) {
/*
* Look again for the entry because the map was
* modified while it was unlocked.
* Specifically, the entry may have been
* clipped, merged, or deleted.
*/
if (!vm_map_lookup_entry(map, saved_start,
&tmp_entry)) {
if (saved_start == start) {
/*
* First_entry has been deleted.
*/
vm_map_unlock(map);
return (KERN_INVALID_ADDRESS);
}
end = saved_start;
rv = KERN_INVALID_ADDRESS;
goto done;
}
if (entry == first_entry)
first_entry = tmp_entry;
else
first_entry = NULL;
entry = tmp_entry;
}
last_timestamp = map->timestamp;
continue;
}
vm_map_clip_start(map, entry, start);
vm_map_clip_end(map, entry, end);
/*
* Mark the entry in case the map lock is released. (See
* above.)
*/
entry->eflags |= MAP_ENTRY_IN_TRANSITION;
/*
* Check the map for holes in the specified region.
*/
if (entry->end < end && (entry->next == &map->header ||
entry->next->start > entry->end)) {
end = entry->end;
rv = KERN_INVALID_ADDRESS;
goto done;
}
/*
* Require that the entry is wired.
*/
if (entry->wired_count == 0 || (user_unwire &&
(entry->eflags & MAP_ENTRY_USER_WIRED) == 0)) {
end = entry->end;
rv = KERN_INVALID_ARGUMENT;
goto done;
}
entry = entry->next;
}
if (first_entry == NULL) {
result = vm_map_lookup_entry(map, start, &first_entry);
KASSERT(result, ("vm_map_unwire: lookup failed"));
}
entry = first_entry;
while (entry != &map->header && entry->start < end) {
if (user_unwire)
entry->eflags &= ~MAP_ENTRY_USER_WIRED;
entry->wired_count--;
if (entry->wired_count == 0) {
/*
* Retain the map lock.
*/
vm_fault_unwire(map, entry->start, entry->end);
}
entry = entry->next;
}
rv = KERN_SUCCESS;
done:
if (first_entry == NULL) {
result = vm_map_lookup_entry(map, start, &first_entry);
KASSERT(result, ("vm_map_unwire: lookup failed"));
}
entry = first_entry;
while (entry != &map->header && entry->start < end) {
KASSERT(entry->eflags & MAP_ENTRY_IN_TRANSITION,
("vm_map_unwire: in-transition flag missing"));
entry->eflags &= ~MAP_ENTRY_IN_TRANSITION;
if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) {
entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP;
need_wakeup = TRUE;
}
vm_map_simplify_entry(map, entry);
entry = entry->next;
}
vm_map_unlock(map);
if (need_wakeup)
vm_map_wakeup(map);
return (rv);
}
/*
* Implement the semantics of mlock
*/

4
sys/vm/vm_map.h
View File

@ -131,6 +131,8 @@ struct vm_map_entry {
#define MAP_ENTRY_BEHAV_MASK 0x00C0
#define MAP_ENTRY_IN_TRANSITION 0x0100 /* entry being changed */
#define MAP_ENTRY_NEEDS_WAKEUP 0x0200 /* waiters in transition */
#define MAP_ENTRY_NOCOREDUMP 0x0400 /* don't include in a core */
#ifdef _KERNEL
@ -316,6 +318,8 @@ void vm_map_simplify_entry (vm_map_t, vm_map_entry_t);
void vm_init2 (void);
int vm_map_stack (vm_map_t, vm_offset_t, vm_size_t, vm_prot_t, vm_prot_t, int);
int vm_map_growstack (struct proc *p, vm_offset_t addr);
int vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
boolean_t user_unwire);
int vmspace_swap_count (struct vmspace *vmspace);
int vm_uiomove(vm_map_t, vm_object_t, off_t, int, vm_offset_t, int *);
#endif /* _KERNEL */