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o Make _vm_object_allocate() and vm_object_allocate() callable

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without holding Giant.
 o Begin documenting the trivial cases of the locking protocol
   on vm_object.
This commit is contained in:
Alan Cox 2002-05-04 20:23:48 +00:00
parent 856f29cf94
commit 79660d837c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=96042
2 changed files with 21 additions and 22 deletions
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36
sys/vm/vm_object.c
View File

@ -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);

7
sys/vm/vm_object.h
View File

@ -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 */