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Instead of looking up a predecessor or successor to the current map

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entry, when that entry has been seen already, keep the
already-looked-up value in a variable and use that instead of looking
it up again.

Approved by: alc, markj (earlier version), kib (earlier version)
Differential Revision: https://reviews.freebsd.org/D22348
This commit is contained in:
Doug Moore 2019-11-20 16:06:48 +00:00
parent 0cb5357037
commit 83704cc236
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=354895
3 changed files with 109 additions and 93 deletions
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9
sys/security/mac/mac_process.c
View File

@ -252,7 +252,7 @@ static void
mac_proc_vm_revoke_recurse(struct thread *td, struct ucred *cred,
struct vm_map *map)
{
vm_map_entry_t vme;
vm_map_entry_t prev, vme;
int result;
vm_prot_t revokeperms;
vm_object_t backing_object, object;
@ -263,8 +263,10 @@ mac_proc_vm_revoke_recurse(struct thread *td, struct ucred *cred,
if (!mac_mmap_revocation)
return;
prev = &map->header;
vm_map_lock(map);
VM_MAP_ENTRY_FOREACH(vme, map) {
for (vme = vm_map_entry_first(map); vme != &map->header;
prev = vme, vme = vm_map_entry_succ(prev)) {
if (vme->eflags & MAP_ENTRY_IS_SUB_MAP) {
mac_proc_vm_revoke_recurse(td, cred,
vme->object.sub_map);
@ -363,8 +365,7 @@ mac_proc_vm_revoke_recurse(struct thread *td, struct ucred *cred,
}
pmap_protect(map->pmap, vme->start, vme->end,
vme->protection & ~revokeperms);
vm_map_try_merge_entries(map, vm_map_entry_pred(vme),
vme);
vm_map_try_merge_entries(map, prev, vme);
}
}
vm_map_unlock(map);

175
sys/vm/vm_map.c
View File

@ -978,6 +978,21 @@ vm_map_entry_max_free_right(vm_map_entry_t root, vm_map_entry_t right_ancestor)
root->right->max_free : right_ancestor->start - root->end);
}
/*
* vm_map_entry_{pred,succ}:
*
* Find the {predecessor, successor} of the entry by taking one step
* in the appropriate direction and backtracking as much as necessary.
*/
static inline vm_map_entry_t
vm_map_entry_pred(vm_map_entry_t entry)
{
return (entry->prev);
}
/* vm_map_entry_succ is defined in vm_map.h. */
#define SPLAY_LEFT_STEP(root, y, rlist, test) do { \
vm_size_t max_free; \
\
@ -1412,7 +1427,7 @@ int
vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
vm_offset_t start, vm_offset_t end, vm_prot_t prot, vm_prot_t max, int cow)
{
vm_map_entry_t new_entry, prev_entry;
vm_map_entry_t new_entry, next_entry, prev_entry;
struct ucred *cred;
vm_eflags_t protoeflags;
vm_inherit_t inheritance;
@ -1443,7 +1458,8 @@ vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
/*
* Assert that the next entry doesn't overlap the end point.
*/
if (vm_map_entry_succ(prev_entry)->start < end)
next_entry = vm_map_entry_succ(prev_entry);
if (next_entry->start < end)
return (KERN_NO_SPACE);
if ((cow & MAP_CREATE_GUARD) != 0 && (object != NULL ||
@ -1538,8 +1554,7 @@ vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
map->size += end - prev_entry->end;
vm_map_entry_resize(map, prev_entry,
end - prev_entry->end);
vm_map_try_merge_entries(map, prev_entry,
vm_map_entry_succ(prev_entry));
vm_map_try_merge_entries(map, prev_entry, next_entry);
return (KERN_SUCCESS);
}
@ -1600,7 +1615,7 @@ vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
* other cases, which are less common.
*/
vm_map_try_merge_entries(map, prev_entry, new_entry);
vm_map_try_merge_entries(map, new_entry, vm_map_entry_succ(new_entry));
vm_map_try_merge_entries(map, new_entry, next_entry);
if ((cow & (MAP_PREFAULT | MAP_PREFAULT_PARTIAL)) != 0) {
vm_map_pmap_enter(map, start, prot, object, OFF_TO_IDX(offset),
@ -2430,7 +2445,7 @@ int
vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
vm_prot_t new_prot, boolean_t set_max)
{
vm_map_entry_t current, entry, in_tran;
vm_map_entry_t current, entry, in_tran, prev_entry;
vm_object_t obj;
struct ucred *cred;
vm_prot_t old_prot;
@ -2555,9 +2570,10 @@ vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
* Otherwise, just simplify entries, since some may have been modified.
* [Note that clipping is not necessary the second time.]
*/
for (current = entry; current->start < end;
vm_map_try_merge_entries(map, vm_map_entry_pred(current), current),
current = vm_map_entry_succ(current)) {
for (prev_entry = vm_map_entry_pred(entry), current = entry;
current->start < end;
vm_map_try_merge_entries(map, prev_entry, current),
prev_entry = current, current = vm_map_entry_succ(current)) {
if (rv != KERN_SUCCESS ||
(current->eflags & MAP_ENTRY_GUARD) != 0)
continue;
@ -2595,7 +2611,7 @@ vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
#undef MASK
}
}
vm_map_try_merge_entries(map, vm_map_entry_pred(current), current);
vm_map_try_merge_entries(map, prev_entry, current);
vm_map_unlock(map);
return (rv);
}
@ -2615,7 +2631,7 @@ vm_map_madvise(
vm_offset_t end,
int behav)
{
vm_map_entry_t current, entry;
vm_map_entry_t current, prev_entry;
bool modify_map;
/*
@ -2654,11 +2670,13 @@ vm_map_madvise(
*/
VM_MAP_RANGE_CHECK(map, start, end);
if (vm_map_lookup_entry(map, start, &entry)) {
if (vm_map_lookup_entry(map, start, &current)) {
if (modify_map)
vm_map_clip_start(map, entry, start);
vm_map_clip_start(map, current, start);
prev_entry = vm_map_entry_pred(current);
} else {
entry = vm_map_entry_succ(entry);
prev_entry = current;
current = vm_map_entry_succ(current);
}
if (modify_map) {
@ -2668,7 +2686,7 @@ vm_map_madvise(
* We clip the vm_map_entry so that behavioral changes are
* limited to the specified address range.
*/
for (current = entry; current->start < end;
for (; current->start < end; prev_entry = current,
current = vm_map_entry_succ(current)) {
if (current->eflags & MAP_ENTRY_IS_SUB_MAP)
continue;
@ -2700,11 +2718,9 @@ vm_map_madvise(
default:
break;
}
vm_map_try_merge_entries(map,
vm_map_entry_pred(current), current);
vm_map_try_merge_entries(map, prev_entry, current);
}
vm_map_try_merge_entries(map, vm_map_entry_pred(current),
current);
vm_map_try_merge_entries(map, prev_entry, current);
vm_map_unlock(map);
} else {
vm_pindex_t pstart, pend;
@ -2716,7 +2732,7 @@ vm_map_madvise(
* Since we don't clip the vm_map_entry, we have to clip
* the vm_object pindex and count.
*/
for (current = entry; current->start < end;
for (; current->start < end;
current = vm_map_entry_succ(current)) {
vm_offset_t useEnd, useStart;
@ -2804,8 +2820,7 @@ int
vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end,
vm_inherit_t new_inheritance)
{
vm_map_entry_t entry;
vm_map_entry_t temp_entry;
vm_map_entry_t entry, prev_entry;
switch (new_inheritance) {
case VM_INHERIT_NONE:
@ -2820,20 +2835,21 @@ vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end,
return (KERN_SUCCESS);
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (vm_map_lookup_entry(map, start, &temp_entry)) {
entry = temp_entry;
if (vm_map_lookup_entry(map, start, &prev_entry)) {
entry = prev_entry;
vm_map_clip_start(map, entry, start);
prev_entry = vm_map_entry_pred(entry);
} else
entry = vm_map_entry_succ(temp_entry);
while (entry->start < end) {
entry = vm_map_entry_succ(prev_entry);
for (; entry->start < end;
prev_entry = entry, entry = vm_map_entry_succ(entry)) {
vm_map_clip_end(map, entry, end);
if ((entry->eflags & MAP_ENTRY_GUARD) == 0 ||
new_inheritance != VM_INHERIT_ZERO)
entry->inheritance = new_inheritance;
vm_map_try_merge_entries(map, vm_map_entry_pred(entry), entry);
entry = vm_map_entry_succ(entry);
vm_map_try_merge_entries(map, prev_entry, entry);
}
vm_map_try_merge_entries(map, vm_map_entry_pred(entry), entry);
vm_map_try_merge_entries(map, prev_entry, entry);
vm_map_unlock(map);
return (KERN_SUCCESS);
}
@ -2896,9 +2912,9 @@ int
vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
int flags)
{
vm_map_entry_t entry, first_entry;
vm_map_entry_t entry, first_entry, next_entry, prev_entry;
int rv;
bool first_iteration, holes_ok, need_wakeup, user_unwire;
bool holes_ok, need_wakeup, user_unwire;
if (start == end)
return (KERN_SUCCESS);
@ -2914,28 +2930,26 @@ vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
return (KERN_INVALID_ADDRESS);
}
}
first_iteration = true;
entry = first_entry;
rv = KERN_SUCCESS;
while (entry->start < end) {
for (entry = first_entry; entry->start < end; entry = next_entry) {
if (entry->eflags & MAP_ENTRY_IN_TRANSITION) {
/*
* We have not yet clipped the entry.
*/
entry = vm_map_entry_in_transition(map, start, &end,
holes_ok, entry);
if (entry == NULL) {
if (first_iteration) {
next_entry = vm_map_entry_in_transition(map, start,
&end, holes_ok, entry);
if (next_entry == NULL) {
if (entry == first_entry) {
vm_map_unlock(map);
return (KERN_INVALID_ADDRESS);
}
rv = KERN_INVALID_ADDRESS;
break;
}
first_entry = first_iteration ? entry : NULL;
first_entry = (entry == first_entry) ?
next_entry : NULL;
continue;
}
first_iteration = false;
vm_map_clip_start(map, entry, start);
vm_map_clip_end(map, entry, end);
/*
@ -2947,13 +2961,13 @@ vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
("owned map entry %p", entry));
entry->eflags |= MAP_ENTRY_IN_TRANSITION;
entry->wiring_thread = curthread;
next_entry = vm_map_entry_succ(entry);
/*
* Check the map for holes in the specified region.
* If holes_ok, skip this check.
*/
if (!holes_ok &&
(entry->end < end &&
vm_map_entry_succ(entry)->start > entry->end)) {
entry->end < end && next_entry->start > entry->end) {
end = entry->end;
rv = KERN_INVALID_ADDRESS;
break;
@ -2967,16 +2981,19 @@ vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
rv = KERN_INVALID_ARGUMENT;
break;
}
entry = vm_map_entry_succ(entry);
}
need_wakeup = false;
if (first_entry == NULL &&
!vm_map_lookup_entry(map, start, &first_entry)) {
KASSERT(holes_ok, ("vm_map_unwire: lookup failed"));
first_entry = vm_map_entry_succ(first_entry);
prev_entry = first_entry;
entry = vm_map_entry_succ(first_entry);
} else {
prev_entry = vm_map_entry_pred(first_entry);
entry = first_entry;
}
for (entry = first_entry; entry->start < end;
entry = vm_map_entry_succ(entry)) {
for (; entry->start < end;
prev_entry = entry, entry = vm_map_entry_succ(entry)) {
/*
* If holes_ok was specified, an empty
* space in the unwired region could have been mapped
@ -3012,9 +3029,9 @@ vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP;
need_wakeup = true;
}
vm_map_try_merge_entries(map, vm_map_entry_pred(entry), entry);
vm_map_try_merge_entries(map, prev_entry, entry);
}
vm_map_try_merge_entries(map, vm_map_entry_pred(entry), entry);
vm_map_try_merge_entries(map, prev_entry, entry);
vm_map_unlock(map);
if (need_wakeup)
vm_map_wakeup(map);
@ -3100,12 +3117,12 @@ vm_map_wire(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags)
int
vm_map_wire_locked(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags)
{
vm_map_entry_t entry, first_entry, tmp_entry;
vm_map_entry_t entry, first_entry, next_entry, prev_entry;
vm_offset_t faddr, saved_end, saved_start;
u_long npages;
u_int last_timestamp;
int rv;
bool first_iteration, holes_ok, need_wakeup, user_wire;
bool holes_ok, need_wakeup, user_wire;
vm_prot_t prot;
VM_MAP_ASSERT_LOCKED(map);
@ -3124,25 +3141,23 @@ vm_map_wire_locked(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags)
else
return (KERN_INVALID_ADDRESS);
}
first_iteration = true;
entry = first_entry;
while (entry->start < end) {
for (entry = first_entry; entry->start < end; entry = next_entry) {
if (entry->eflags & MAP_ENTRY_IN_TRANSITION) {
/*
* We have not yet clipped the entry.
*/
entry = vm_map_entry_in_transition(map, start, &end,
holes_ok, entry);
if (entry == NULL) {
if (first_iteration)
next_entry = vm_map_entry_in_transition(map, start,
&end, holes_ok, entry);
if (next_entry == NULL) {
if (entry == first_entry)
return (KERN_INVALID_ADDRESS);
rv = KERN_INVALID_ADDRESS;
goto done;
}
first_entry = first_iteration ? entry : NULL;
first_entry = (entry == first_entry) ?
next_entry : NULL;
continue;
}
first_iteration = false;
vm_map_clip_start(map, entry, start);
vm_map_clip_end(map, entry, end);
/*
@ -3205,15 +3220,13 @@ vm_map_wire_locked(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags)
* deleted.
*/
if (!vm_map_lookup_entry(map, saved_start,
&tmp_entry))
&next_entry))
KASSERT(false,
("vm_map_wire: lookup failed"));
if (entry == first_entry)
first_entry = tmp_entry;
else
first_entry = NULL;
entry = tmp_entry;
while (entry->end < saved_end) {
first_entry = (entry == first_entry) ?
next_entry : NULL;
for (entry = next_entry; entry->end < saved_end;
entry = vm_map_entry_succ(entry)) {
/*
* In case of failure, handle entries
* that were not fully wired here;
@ -3224,7 +3237,6 @@ vm_map_wire_locked(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags)
faddr < entry->end)
vm_map_wire_entry_failure(map,
entry, faddr);
entry = vm_map_entry_succ(entry);
}
}
if (rv != KERN_SUCCESS) {
@ -3242,14 +3254,13 @@ vm_map_wire_locked(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags)
* Check the map for holes in the specified region.
* If holes_ok was specified, skip this check.
*/
next_entry = vm_map_entry_succ(entry);
if (!holes_ok &&
entry->end < end &&
vm_map_entry_succ(entry)->start > entry->end) {
entry->end < end && next_entry->start > entry->end) {
end = entry->end;
rv = KERN_INVALID_ADDRESS;
goto done;
}
entry = vm_map_entry_succ(entry);
}
rv = KERN_SUCCESS;
done:
@ -3257,10 +3268,14 @@ vm_map_wire_locked(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags)
if (first_entry == NULL &&
!vm_map_lookup_entry(map, start, &first_entry)) {
KASSERT(holes_ok, ("vm_map_wire: lookup failed"));
first_entry = vm_map_entry_succ(first_entry);
prev_entry = first_entry;
entry = vm_map_entry_succ(first_entry);
} else {
prev_entry = vm_map_entry_pred(first_entry);
entry = first_entry;
}
for (entry = first_entry; entry->start < end;
entry = vm_map_entry_succ(entry)) {
for (; entry->start < end;
prev_entry = entry, entry = vm_map_entry_succ(entry)) {
/*
* If holes_ok was specified, an empty
* space in the unwired region could have been mapped
@ -3313,9 +3328,9 @@ vm_map_wire_locked(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags)
entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP;
need_wakeup = true;
}
vm_map_try_merge_entries(map, vm_map_entry_pred(entry), entry);
vm_map_try_merge_entries(map, prev_entry, entry);
}
vm_map_try_merge_entries(map, vm_map_entry_pred(entry), entry);
vm_map_try_merge_entries(map, prev_entry, entry);
if (need_wakeup)
vm_map_wakeup(map);
return (rv);
@ -3345,8 +3360,7 @@ vm_map_sync(
boolean_t syncio,
boolean_t invalidate)
{
vm_map_entry_t current;
vm_map_entry_t entry;
vm_map_entry_t current, entry, next_entry;
vm_size_t size;
vm_object_t object;
vm_ooffset_t offset;
@ -3366,13 +3380,14 @@ vm_map_sync(
* Make a first pass to check for user-wired memory and holes.
*/
for (current = entry; current->start < end;
current = vm_map_entry_succ(current)) {
current = next_entry) {
if (invalidate && (current->eflags & MAP_ENTRY_USER_WIRED)) {
vm_map_unlock_read(map);
return (KERN_INVALID_ARGUMENT);
}
next_entry = vm_map_entry_succ(current);
if (end > current->end &&
current->end != vm_map_entry_succ(current)->start) {
current->end != next_entry->start) {
vm_map_unlock_read(map);
return (KERN_INVALID_ADDRESS);
}
@ -3914,7 +3929,7 @@ vmspace_fork(struct vmspace *vm1, vm_ooffset_t *fork_charge)
new_map->anon_loc = old_map->anon_loc;
old_entry = old_map->header.next;
old_entry = vm_map_entry_first(old_map);
while (old_entry != &old_map->header) {
if (old_entry->eflags & MAP_ENTRY_IS_SUB_MAP)

18
sys/vm/vm_map.h
View File

@ -420,6 +420,13 @@ int vm_map_lookup_locked(vm_map_t *, vm_offset_t, vm_prot_t, vm_map_entry_t *, v
void vm_map_lookup_done (vm_map_t, vm_map_entry_t);
boolean_t vm_map_lookup_entry (vm_map_t, vm_offset_t, vm_map_entry_t *);
static inline vm_map_entry_t
vm_map_entry_first(vm_map_t map)
{
return (map->header.next);
}
static inline vm_map_entry_t
vm_map_entry_succ(vm_map_entry_t entry)
{
@ -427,15 +434,8 @@ vm_map_entry_succ(vm_map_entry_t entry)
return (entry->next);
}
static inline vm_map_entry_t
vm_map_entry_pred(vm_map_entry_t entry)
{
return (entry->prev);
}
#define VM_MAP_ENTRY_FOREACH(it, map) \
for ((it) = (map)->header.next; \
#define VM_MAP_ENTRY_FOREACH(it, map) \
for ((it) = vm_map_entry_first(map); \
(it) != &(map)->header; \
(it) = vm_map_entry_succ(it))
int vm_map_protect (vm_map_t, vm_offset_t, vm_offset_t, vm_prot_t, boolean_t);