Author: kib
Date: Sun Jan 8 16:59:07 2017
New Revision: 311687
URL: https://svnweb.freebsd.org/changeset/base/311687
Log:
MFC r267546 (by alc):
Tidy up the early parts of vm_map_insert().
MFC r267645 (by alc):
When MAP_STACK_GROWS_{DOWN,UP} are passed to vm_map_insert() set the
corresponding flag(s) in the new map entry.
Pass MAP_STACK_GROWS_DOWN to vm_map_insert() from vm_map_growstack() when
extending the stack in the downward direction.
MFC r267850 (by alc):
Place the check that blocks map entry coalescing on stack entries in
vm_map_simplify_entry().
MFC r267917 (by alc):
Delay the call to crhold() in vm_map_insert() until we know that we won't
have to undo it by calling crfree().
Eliminate an unnecessary variable from vm_map_insert().
MFC r311014:
Style fixes for vm_map_insert().
Tested by: pho
Modified:
stable/10/sys/vm/vm_map.c
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/sys/vm/vm_map.c
==============================================================================
--- stable/10/sys/vm/vm_map.c Sun Jan 8 16:55:59 2017 (r311686)
+++ stable/10/sys/vm/vm_map.c Sun Jan 8 16:59:07 2017 (r311687)
@@ -1130,24 +1130,24 @@ vm_map_lookup_entry(
*/
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_offset_t start, vm_offset_t end, vm_prot_t prot, vm_prot_t max, int cow)
{
- vm_map_entry_t new_entry;
- vm_map_entry_t prev_entry;
- vm_map_entry_t temp_entry;
- vm_eflags_t protoeflags;
+ vm_map_entry_t new_entry, prev_entry, temp_entry;
struct ucred *cred;
+ vm_eflags_t protoeflags;
vm_inherit_t inheritance;
- boolean_t charge_prev_obj;
VM_MAP_ASSERT_LOCKED(map);
+ KASSERT((object != kmem_object && object != kernel_object) ||
+ (cow & MAP_COPY_ON_WRITE) == 0,
+ ("vm_map_insert: kmem or kernel object and COW"));
+ KASSERT(object == NULL || (cow & MAP_NOFAULT) == 0,
+ ("vm_map_insert: paradoxical MAP_NOFAULT request"));
/*
* Check that the start and end points are not bogus.
*/
- if ((start < map->min_offset) || (end > map->max_offset) ||
- (start >= end))
+ if (start < map->min_offset || end > map->max_offset || start >= end)
return (KERN_INVALID_ADDRESS);
/*
@@ -1162,26 +1162,22 @@ vm_map_insert(vm_map_t map, vm_object_t
/*
* Assert that the next entry doesn't overlap the end point.
*/
- if ((prev_entry->next != &map->header) &&
- (prev_entry->next->start < end))
+ if (prev_entry->next != &map->header && prev_entry->next->start < end)
return (KERN_NO_SPACE);
protoeflags = 0;
- charge_prev_obj = FALSE;
-
if (cow & MAP_COPY_ON_WRITE)
- protoeflags |= MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY;
-
- if (cow & MAP_NOFAULT) {
+ protoeflags |= MAP_ENTRY_COW | MAP_ENTRY_NEEDS_COPY;
+ if (cow & MAP_NOFAULT)
protoeflags |= MAP_ENTRY_NOFAULT;
-
- KASSERT(object == NULL,
- ("vm_map_insert: paradoxical MAP_NOFAULT request"));
- }
if (cow & MAP_DISABLE_SYNCER)
protoeflags |= MAP_ENTRY_NOSYNC;
if (cow & MAP_DISABLE_COREDUMP)
protoeflags |= MAP_ENTRY_NOCOREDUMP;
+ if (cow & MAP_STACK_GROWS_DOWN)
+ protoeflags |= MAP_ENTRY_GROWS_DOWN;
+ if (cow & MAP_STACK_GROWS_UP)
+ protoeflags |= MAP_ENTRY_GROWS_UP;
if (cow & MAP_VN_WRITECOUNT)
protoeflags |= MAP_ENTRY_VN_WRITECNT;
if (cow & MAP_INHERIT_SHARE)
@@ -1190,23 +1186,17 @@ vm_map_insert(vm_map_t map, vm_object_t
inheritance = VM_INHERIT_DEFAULT;
cred = NULL;
- KASSERT((object != kmem_object && object != kernel_object) ||
- ((object == kmem_object || object == kernel_object) &&
- !(protoeflags & MAP_ENTRY_NEEDS_COPY)),
- ("kmem or kernel object and cow"));
if (cow & (MAP_ACC_NO_CHARGE | MAP_NOFAULT))
goto charged;
if ((cow & MAP_ACC_CHARGED) || ((prot & VM_PROT_WRITE) &&
((protoeflags & MAP_ENTRY_NEEDS_COPY) || object == NULL))) {
if (!(cow & MAP_ACC_CHARGED) && !swap_reserve(end - start))
return (KERN_RESOURCE_SHORTAGE);
- KASSERT(object == NULL || (protoeflags & MAP_ENTRY_NEEDS_COPY)
||
+ KASSERT(object == NULL ||
+ (protoeflags & MAP_ENTRY_NEEDS_COPY) != 0 ||
object->cred == NULL,
- ("OVERCOMMIT: vm_map_insert o %p", object));
+ ("overcommit: vm_map_insert o %p", object));
cred = curthread->td_ucred;
- crhold(cred);
- if (object == NULL && !(protoeflags & MAP_ENTRY_NEEDS_COPY))
- charge_prev_obj = TRUE;
}
charged:
@@ -1225,33 +1215,30 @@ charged:
if (object->ref_count > 1 || object->shadow_count != 0)
vm_object_clear_flag(object, OBJ_ONEMAPPING);
VM_OBJECT_WUNLOCK(object);
- }
- else if ((prev_entry != &map->header) &&
- (prev_entry->eflags == protoeflags) &&
- (cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 &&
- (prev_entry->end == start) &&
- (prev_entry->wired_count == 0) &&
- (prev_entry->cred == cred ||
- (prev_entry->object.vm_object != NULL &&
- (prev_entry->object.vm_object->cred == cred))) &&
- vm_object_coalesce(prev_entry->object.vm_object,
- prev_entry->offset,
- (vm_size_t)(prev_entry->end - prev_entry->start),
- (vm_size_t)(end - prev_entry->end), charge_prev_obj)) {
+ } else if (prev_entry != &map->header &&
+ prev_entry->eflags == protoeflags &&
+ (cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 &&
+ prev_entry->end == start && prev_entry->wired_count == 0 &&
+ (prev_entry->cred == cred ||
+ (prev_entry->object.vm_object != NULL &&
+ prev_entry->object.vm_object->cred == cred)) &&
+ vm_object_coalesce(prev_entry->object.vm_object,
+ prev_entry->offset,
+ (vm_size_t)(prev_entry->end - prev_entry->start),
+ (vm_size_t)(end - prev_entry->end), cred != NULL &&
+ (protoeflags & MAP_ENTRY_NEEDS_COPY) == 0)) {
/*
* 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 == inheritance) &&
- (prev_entry->protection == prot) &&
- (prev_entry->max_protection == max)) {
- map->size += (end - prev_entry->end);
+ if (prev_entry->inheritance == inheritance &&
+ prev_entry->protection == prot &&
+ prev_entry->max_protection == max) {
+ map->size += end - prev_entry->end;
prev_entry->end = end;
vm_map_entry_resize_free(map, prev_entry);
vm_map_simplify_entry(map, prev_entry);
- if (cred != NULL)
- crfree(cred);
return (KERN_SUCCESS);
}
@@ -1263,21 +1250,16 @@ charged:
*/
object = prev_entry->object.vm_object;
offset = prev_entry->offset +
- (prev_entry->end - prev_entry->start);
+ (prev_entry->end - prev_entry->start);
vm_object_reference(object);
if (cred != NULL && object != NULL && object->cred != NULL &&
!(prev_entry->eflags & MAP_ENTRY_NEEDS_COPY)) {
/* Object already accounts for this uid. */
- crfree(cred);
cred = NULL;
}
}
-
- /*
- * 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.
- */
+ if (cred != NULL)
+ crhold(cred);
/*
* Create a new entry
@@ -1301,7 +1283,7 @@ charged:
new_entry->next_read = OFF_TO_IDX(offset);
KASSERT(cred == NULL || !ENTRY_CHARGED(new_entry),
- ("OVERCOMMIT: vm_map_insert leaks vm_map %p", new_entry));
+ ("overcommit: vm_map_insert leaks vm_map %p", new_entry));
new_entry->cred = cred;
/*
@@ -1311,17 +1293,16 @@ charged:
map->size += new_entry->end - new_entry->start;
/*
- * It may be possible to merge the new entry with the next and/or
- * previous entries. However, due to MAP_STACK_* being a hack, a
- * panic can result from merging such entries.
- */
- if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0)
- vm_map_simplify_entry(map, new_entry);
-
- if (cow & (MAP_PREFAULT|MAP_PREFAULT_PARTIAL)) {
- vm_map_pmap_enter(map, start, prot,
- object, OFF_TO_IDX(offset), end - start,
- cow & MAP_PREFAULT_PARTIAL);
+ * Try to coalesce the new entry with both the previous and next
+ * entries in the list. Previously, we only attempted to coalesce
+ * with the previous entry when object is NULL. Here, we handle the
+ * other cases, which are less common.
+ */
+ vm_map_simplify_entry(map, new_entry);
+
+ if ((cow & (MAP_PREFAULT | MAP_PREFAULT_PARTIAL)) != 0) {
+ vm_map_pmap_enter(map, start, prot, object, OFF_TO_IDX(offset),
+ end - start, cow & MAP_PREFAULT_PARTIAL);
}
return (KERN_SUCCESS);
@@ -1531,7 +1512,8 @@ vm_map_simplify_entry(vm_map_t map, vm_m
vm_map_entry_t next, prev;
vm_size_t prevsize, esize;
- if (entry->eflags & (MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_IS_SUB_MAP))
+ if ((entry->eflags & (MAP_ENTRY_GROWS_DOWN | MAP_ENTRY_GROWS_UP |
+ MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_IS_SUB_MAP)) != 0)
return;
prev = entry->prev;
@@ -3527,17 +3509,17 @@ vm_map_stack_locked(vm_map_t map, vm_off
/* Now set the avail_ssize amount. */
if (rv == KERN_SUCCESS) {
- if (prev_entry != &map->header)
- vm_map_clip_end(map, prev_entry, bot);
new_entry = prev_entry->next;
if (new_entry->end != top || new_entry->start != bot)
panic("Bad entry start/end for new stack entry");
new_entry->avail_ssize = max_ssize - init_ssize;
- if (orient & MAP_STACK_GROWS_DOWN)
- new_entry->eflags |= MAP_ENTRY_GROWS_DOWN;
- if (orient & MAP_STACK_GROWS_UP)
- new_entry->eflags |= MAP_ENTRY_GROWS_UP;
+ KASSERT((orient & MAP_STACK_GROWS_DOWN) == 0 ||
+ (new_entry->eflags & MAP_ENTRY_GROWS_DOWN) != 0,
+ ("new entry lacks MAP_ENTRY_GROWS_DOWN"));
+ KASSERT((orient & MAP_STACK_GROWS_UP) == 0 ||
+ (new_entry->eflags & MAP_ENTRY_GROWS_UP) != 0,
+ ("new entry lacks MAP_ENTRY_GROWS_UP"));
}
return (rv);
@@ -3764,21 +3746,21 @@ Retry:
}
rv = vm_map_insert(map, NULL, 0, addr, stack_entry->start,
- next_entry->protection, next_entry->max_protection, 0);
+ next_entry->protection, next_entry->max_protection,
+ MAP_STACK_GROWS_DOWN);
/* Adjust the available stack space by the amount we grew. */
if (rv == KERN_SUCCESS) {
- if (prev_entry != &map->header)
- vm_map_clip_end(map, prev_entry, addr);
new_entry = prev_entry->next;
KASSERT(new_entry == stack_entry->prev, ("foo"));
KASSERT(new_entry->end == stack_entry->start, ("foo"));
KASSERT(new_entry->start == addr, ("foo"));
+ KASSERT((new_entry->eflags & MAP_ENTRY_GROWS_DOWN) !=
+ 0, ("new entry lacks MAP_ENTRY_GROWS_DOWN"));
grow_amount = new_entry->end - new_entry->start;
new_entry->avail_ssize = stack_entry->avail_ssize -
grow_amount;
stack_entry->eflags &= ~MAP_ENTRY_GROWS_DOWN;
- new_entry->eflags |= MAP_ENTRY_GROWS_DOWN;
}
} else {
/*
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