Page MenuHomeFreeBSD
Files F147515722

D54338.diff
No OneTemporary
Actions

D54338.diff
View Options

diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -1620,6 +1620,7 @@
vm_inherit_t inheritance;
u_long bdry;
u_int bidx;
+ int cflags;
VM_MAP_ASSERT_LOCKED(map);
KASSERT(object != kernel_object ||
@@ -1696,20 +1697,36 @@
}
cred = NULL;
- if ((cow & (MAP_ACC_NO_CHARGE | MAP_NOFAULT | MAP_CREATE_GUARD)) != 0)
- 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) != 0 ||
- object->cred == NULL,
- ("overcommit: vm_map_insert o %p", object));
- cred = curthread->td_ucred;
+ if ((cow & (MAP_ACC_NO_CHARGE | MAP_NOFAULT | MAP_CREATE_GUARD)) != 0) {
+ cflags = OBJCO_NO_CHARGE;
+ } else {
+ cflags = 0;
+ if ((cow & MAP_ACC_CHARGED) != 0 ||
+ ((prot & VM_PROT_WRITE) != 0 &&
+ ((protoeflags & MAP_ENTRY_NEEDS_COPY) != 0 ||
+ object == NULL))) {
+ if ((cow & MAP_ACC_CHARGED) == 0) {
+ if (!swap_reserve(end - start))
+ return (KERN_RESOURCE_SHORTAGE);
+
+ /*
+ * Only inform vm_object_coalesce()
+ * that the object was charged if
+ * there is no need for CoW, so the
+ * swap amount reserved is applicable
+ * to the prev_entry->object.
+ */
+ if ((protoeflags & MAP_ENTRY_NEEDS_COPY) == 0)
+ cflags |= OBJCO_CHARGED;
+ }
+ KASSERT(object == NULL ||
+ (protoeflags & MAP_ENTRY_NEEDS_COPY) != 0 ||
+ object->cred == NULL,
+ ("overcommit: vm_map_insert o %p", object));
+ cred = curthread->td_ucred;
+ }
}
-charged:
/* Expand the kernel pmap, if necessary. */
if (map == kernel_map && end > kernel_vm_end) {
int rv;
@@ -1741,8 +1758,7 @@
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)) {
+ (vm_size_t)(end - prev_entry->end), cflags)) {
/*
* We were able to extend the object. Determine if we
* can extend the previous map entry to include the
diff --git a/sys/vm/vm_object.h b/sys/vm/vm_object.h
--- a/sys/vm/vm_object.h
+++ b/sys/vm/vm_object.h
@@ -228,6 +228,12 @@
#define OBJPR_NOTMAPPED 0x2 /* Don't unmap pages. */
#define OBJPR_VALIDONLY 0x4 /* Ignore invalid pages. */
+/*
+ * Options for vm_object_coalesce().
+ */
+#define OBJCO_CHARGED 0x1 /* The next_size was charged already */
+#define OBJCO_NO_CHARGE 0x2 /* Do not do swap accounting at all */
+
TAILQ_HEAD(object_q, vm_object);
extern struct object_q vm_object_list; /* list of allocated objects */
@@ -354,7 +360,7 @@
vm_size_t);
vm_object_t vm_object_allocate_dyn(objtype_t, vm_pindex_t, u_short);
boolean_t vm_object_coalesce(vm_object_t, vm_ooffset_t, vm_size_t, vm_size_t,
- boolean_t);
+ int);
void vm_object_collapse (vm_object_t);
void vm_object_deallocate (vm_object_t);
void vm_object_destroy (vm_object_t);
diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c
--- a/sys/vm/vm_object.c
+++ b/sys/vm/vm_object.c
@@ -2161,7 +2161,7 @@
*/
boolean_t
vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset,
- vm_size_t prev_size, vm_size_t next_size, boolean_t reserved)
+ vm_size_t prev_size, vm_size_t next_size, int cflags)
{
vm_pindex_t next_end, next_pindex;
@@ -2202,8 +2202,7 @@
/*
* Account for the charge.
*/
- if (prev_object->cred != NULL &&
- next_pindex + next_size > prev_object->size) {
+ if (prev_object->cred != NULL && (cflags & OBJCO_NO_CHARGE) == 0) {
/*
* If prev_object was charged, then this mapping,
* although not charged now, may become writable
@@ -2214,14 +2213,36 @@
* entry, and swap reservation for this entry is
* managed in appropriate time.
*/
- vm_size_t charge = ptoa(next_pindex + next_size -
- prev_object->size);
- if (!reserved &&
- !swap_reserve_by_cred(charge, prev_object->cred)) {
- VM_OBJECT_WUNLOCK(prev_object);
- return (FALSE);
+ if (next_end > prev_object->size) {
+ vm_size_t charge = ptoa(next_end - prev_object->size);
+
+ if ((cflags & OBJCO_CHARGED) == 0) {
+ if (!swap_reserve_by_cred(charge,
+ prev_object->cred)) {
+ VM_OBJECT_WUNLOCK(prev_object);
+ return (FALSE);
+ }
+ } else if (prev_object->size > next_pindex) {
+ /*
+ * The caller charged, but:
+ * - the object has already accounted for the
+ * space,
+ * - and the object end is between previous
+ * mapping end and next_end.
+ */
+ swap_release_by_cred(ptoa(prev_object->size -
+ next_pindex), prev_object->cred);
+ }
+ prev_object->charge += charge;
+ } else if ((cflags & OBJCO_CHARGED) != 0) {
+ /*
+ * The caller charged, but the object has
+ * already accounted for the space. Whole new
+ * mapping charge should be released,
+ */
+ swap_release_by_cred(ptoa(next_size),
+ prev_object->cred);
}
- prev_object->charge += charge;
}
/*

File Metadata

Mime Type
text/plain
Expires
Thu, Mar 12, 1:59 PM (6 h, 6 m)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
29585349
Default Alt Text
D54338.diff (5 KB)

Event Timeline