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Reduce the memory footprint for prop_bool_t objects significantly, taking

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adavantage of the immutability of these objects:

Statically allocate a TRUE object and a FALSE object, and simply return
references to those objects for create and copy operations.
This commit is contained in:
thorpej 2006-07-05 20:29:28 +00:00
parent 202456461a
commit 2f3beab89e
1 changed files with 42 additions and 18 deletions
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60
common/lib/libprop/prop_bool.c
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@ -1,4 +1,4 @@
/* $NetBSD: prop_bool.c,v 1.2 2006/05/18 03:05:19 thorpej Exp $ */
/* $NetBSD: prop_bool.c,v 1.3 2006/07/05 20:29:28 thorpej Exp $ */
/*-
* Copyright (c) 2006 The NetBSD Foundation, Inc.
@ -44,7 +44,11 @@ struct _prop_bool {
boolean_t pb_value;
};
_PROP_POOL_INIT(_prop_bool_pool, sizeof(struct _prop_bool), "propbool")
static struct _prop_bool _prop_bool_true;
static struct _prop_bool _prop_bool_false;
_PROP_MUTEX_DECL(_prop_bool_initialized_mutex)
static boolean_t _prop_bool_initialized;
static void _prop_bool_free(void *);
static boolean_t _prop_bool_externalize(
@ -66,7 +70,11 @@ static void
_prop_bool_free(void *v)
{
_PROP_POOL_PUT(_prop_bool_pool, v);
/*
* This should never happen as we "leak" our initial reference
* count.
*/
/* XXX forced assertion failure? */
}
static boolean_t
@ -87,19 +95,38 @@ _prop_bool_equals(void *v1, void *v2)
_PROP_ASSERT(prop_object_is_bool(b1));
_PROP_ASSERT(prop_object_is_bool(b2));
return (b1->pb_value == b2->pb_value);
/*
* Since we only ever allocate one true and one false,
* save ourselves a couple of memory operations.
*/
return (b1 == b2);
}
static prop_bool_t
_prop_bool_alloc(void)
_prop_bool_alloc(boolean_t val)
{
prop_bool_t pb;
pb = _PROP_POOL_GET(_prop_bool_pool);
if (pb != NULL) {
_prop_object_init(&pb->pb_obj, &_prop_object_type_bool);
if (! _prop_bool_initialized) {
_PROP_MUTEX_LOCK(_prop_bool_initialized_mutex);
if (! _prop_bool_initialized) {
_prop_object_init(&_prop_bool_true.pb_obj,
&_prop_object_type_bool);
_prop_bool_true.pb_value = TRUE;
_prop_object_init(&_prop_bool_false.pb_obj,
&_prop_object_type_bool);
_prop_bool_false.pb_value = FALSE;
_prop_bool_initialized = TRUE;
}
_PROP_MUTEX_UNLOCK(_prop_bool_initialized_mutex);
}
pb = val ? &_prop_bool_true : &_prop_bool_false;
prop_object_retain(pb);
return (pb);
}
@ -111,12 +138,8 @@ _prop_bool_alloc(void)
prop_bool_t
prop_bool_create(boolean_t val)
{
prop_bool_t pb;
pb = _prop_bool_alloc();
if (pb != NULL)
pb->pb_value = val;
return (pb);
return (_prop_bool_alloc(val));
}
/*
@ -126,14 +149,15 @@ prop_bool_create(boolean_t val)
prop_bool_t
prop_bool_copy(prop_bool_t opb)
{
prop_bool_t pb;
_PROP_ASSERT(prop_object_is_bool(opb));
pb = _prop_bool_alloc();
if (pb != NULL)
pb->pb_value = opb->pb_value;
return (pb);
/*
* Because we only ever allocate one true and one false, this
* can be reduced to a simple retain operation.
*/
prop_object_retain(opb);
return (opb);
}
/*