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authoralc <alc@FreeBSD.org>2002-05-04 20:23:48 +0000
committeralc <alc@FreeBSD.org>2002-05-04 20:23:48 +0000
commitc281c83bd5bf4d6045f082692f107fd7781140a3 (patch)
tree7846226132e03d6288f141434b92a11b8050e604 /sys
parent8ffbddb82f212c7ce9a879dd1387cb7e60f22692 (diff)
downloadFreeBSD-src-c281c83bd5bf4d6045f082692f107fd7781140a3.zip
FreeBSD-src-c281c83bd5bf4d6045f082692f107fd7781140a3.tar.gz
o Make _vm_object_allocate() and vm_object_allocate() callable
without holding Giant. o Begin documenting the trivial cases of the locking protocol on vm_object.
Diffstat (limited to 'sys')
-rw-r--r--sys/vm/vm_object.c36
-rw-r--r--sys/vm/vm_object.h7
2 files changed, 21 insertions, 22 deletions
diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c
index 5d13cac..1c47fa7 100644
--- a/sys/vm/vm_object.c
+++ b/sys/vm/vm_object.c
@@ -146,8 +146,6 @@ extern int vm_pageout_page_count;
static long object_collapses;
static long object_bypasses;
-static int next_index;
-static int object_hash_rand;
static uma_zone_t obj_zone;
#define VM_OBJECTS_INIT 256
@@ -190,9 +188,9 @@ vm_object_zinit(void *mem, int size)
void
_vm_object_allocate(objtype_t type, vm_size_t size, vm_object_t object)
{
- int incr;
-
- GIANT_REQUIRED;
+ static int next_index;
+ static int object_hash_rand;
+ int exp, incr;
TAILQ_INIT(&object->memq);
TAILQ_INIT(&object->shadow_head);
@@ -203,12 +201,14 @@ _vm_object_allocate(objtype_t type, vm_size_t size, vm_object_t object)
object->flags = 0;
if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP))
vm_object_set_flag(object, OBJ_ONEMAPPING);
- object->pg_color = next_index;
- if (size > (PQ_L2_SIZE / 3 + PQ_PRIME1))
- incr = PQ_L2_SIZE / 3 + PQ_PRIME1;
- else
- incr = size;
- next_index = (next_index + incr) & PQ_L2_MASK;
+ do {
+ object->pg_color = next_index;
+ if (size > (PQ_L2_SIZE / 3 + PQ_PRIME1))
+ incr = PQ_L2_SIZE / 3 + PQ_PRIME1;
+ else
+ incr = size;
+ } while (!atomic_cmpset_int(&next_index, object->pg_color,
+ (object->pg_color + incr) & PQ_L2_MASK));
object->handle = NULL;
object->backing_object = NULL;
object->backing_object_offset = (vm_ooffset_t) 0;
@@ -218,15 +218,16 @@ _vm_object_allocate(objtype_t type, vm_size_t size, vm_object_t object)
* increments plus 1 more to offset it a little more by the time
* it wraps around.
*/
- object->hash_rand = object_hash_rand - 129;
+ do {
+ exp = object_hash_rand;
+ object->hash_rand = exp - 129;
+ } while (!atomic_cmpset_int(&object_hash_rand, exp, object->hash_rand));
- object->generation++;
+ object->generation++; /* atomicity needed? XXX */
mtx_lock(&vm_object_list_mtx);
TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
mtx_unlock(&vm_object_list_mtx);
-
- object_hash_rand = object->hash_rand;
}
/*
@@ -237,8 +238,6 @@ _vm_object_allocate(objtype_t type, vm_size_t size, vm_object_t object)
void
vm_object_init(void)
{
- GIANT_REQUIRED;
-
TAILQ_INIT(&vm_object_list);
mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF);
@@ -267,7 +266,6 @@ vm_object_init2(void)
void
vm_object_set_flag(vm_object_t object, u_short bits)
{
- GIANT_REQUIRED;
object->flags |= bits;
}
@@ -347,8 +345,6 @@ vm_object_allocate(objtype_t type, vm_size_t size)
{
vm_object_t result;
- GIANT_REQUIRED;
-
result = (vm_object_t) uma_zalloc(obj_zone, M_WAITOK);
_vm_object_allocate(type, size, result);
diff --git a/sys/vm/vm_object.h b/sys/vm/vm_object.h
index 62244a9..97f12de 100644
--- a/sys/vm/vm_object.h
+++ b/sys/vm/vm_object.h
@@ -82,6 +82,9 @@ typedef u_char objtype_t;
*
* vm_object_t Virtual memory object.
*
+ * List of locks
+ * (c) const until freed
+ *
*/
struct vm_object {
@@ -93,10 +96,10 @@ struct vm_object {
vm_size_t size; /* Object size */
int ref_count; /* How many refs?? */
int shadow_count; /* how many objects that this is a shadow for */
- int hash_rand; /* vm hash table randomizer */
+ int hash_rand; /* (c) hash table randomizer */
objtype_t type; /* type of pager */
u_short flags; /* see below */
- u_short pg_color; /* color of first page in obj */
+ u_short pg_color; /* (c) color of first page in obj */
u_short paging_in_progress; /* Paging (in or out) so don't collapse or destroy */
int resident_page_count; /* number of resident pages */
struct vm_object *backing_object; /* object that I'm a shadow of */
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