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From c774e89387a43d737abbdd99781a294c1cceebb2 Mon Sep 17 00:00:00 2001
From: Richard Braun <rbraun@sceen.net>
Date: Sun, 7 Feb 2016 14:08:24 +0100
Subject: [PATCH gnumach 2/2] Fix page cache accounting
* vm/vm_object.c (vm_object_bootstrap): Set template object `cached'
member to FALSE.
(vm_object_cache_add, vm_object_cache_remove): New functions.
(vm_object_collect, vm_object_deallocate, vm_object_lookup,
vm_object_lookup_name, vm_object_destroy): Use new cache management functions.
(vm_object_terminate, vm_object_collapse): Make sure object isn't cached.
* vm/vm_object.h (struct vm_object): New `cached' member.
---
vm/vm_object.c | 70 +++++++++++++++++++++++++++++++++-------------------------
vm/vm_object.h | 3 ++-
2 files changed, 42 insertions(+), 31 deletions(-)
diff --git a/vm/vm_object.c b/vm/vm_object.c
index 9a019f6..526b6f3 100644
--- a/vm/vm_object.c
+++ b/vm/vm_object.c
@@ -300,6 +300,7 @@ void vm_object_bootstrap(void)
vm_object_template.paging_in_progress = 0;
vm_object_template.can_persist = FALSE;
+ vm_object_template.cached = FALSE;
vm_object_template.internal = TRUE;
vm_object_template.temporary = TRUE;
vm_object_template.alive = TRUE;
@@ -345,6 +346,33 @@ void vm_object_init(void)
IKOT_PAGING_NAME);
}
+/*
+ * Object cache management functions.
+ *
+ * Both the cache and the object must be locked
+ * before calling these functions.
+ */
+
+static void vm_object_cache_add(
+ vm_object_t object)
+{
+ assert(!object->cached);
+ queue_enter(&vm_object_cached_list, object, vm_object_t, cached_list);
+ vm_object_cached_count++;
+ vm_object_cached_pages_update(object->resident_page_count);
+ object->cached = TRUE;
+}
+
+static void vm_object_cache_remove(
+ vm_object_t object)
+{
+ assert(object->cached);
+ queue_remove(&vm_object_cached_list, object, vm_object_t, cached_list);
+ vm_object_cached_count--;
+ vm_object_cached_pages_update(-object->resident_page_count);
+ object->cached = FALSE;
+}
+
void vm_object_collect(
register vm_object_t object)
{
@@ -368,7 +396,7 @@ void vm_object_collect(
return;
}
- queue_remove(&vm_object_cached_list, object, vm_object_t, cached_list);
+ vm_object_cache_remove(object);
vm_object_terminate(object);
}
@@ -435,12 +463,8 @@ void vm_object_deallocate(
* it in the cache.
*/
if (object->can_persist && (object->resident_page_count > 0)) {
- queue_enter(&vm_object_cached_list, object,
- vm_object_t, cached_list);
- vm_object_cached_count++;
- vm_object_cached_pages_update(object->resident_page_count);
+ vm_object_cache_add(object);
vm_object_cache_unlock();
-
vm_object_unlock(object);
return;
}
@@ -601,6 +625,7 @@ void vm_object_terminate(
assert(object->ref_count == 0);
assert(object->paging_in_progress == 0);
+ assert(!object->cached);
/*
* Throw away port rights... note that they may
@@ -1803,12 +1828,8 @@ vm_object_t vm_object_lookup(
assert(object->alive);
- if (object->ref_count == 0) {
- queue_remove(&vm_object_cached_list, object,
- vm_object_t, cached_list);
- vm_object_cached_count--;
- vm_object_cached_pages_update(-object->resident_page_count);
- }
+ if (object->ref_count == 0)
+ vm_object_cache_remove(object);
object->ref_count++;
vm_object_unlock(object);
@@ -1835,12 +1856,8 @@ vm_object_t vm_object_lookup_name(
assert(object->alive);
- if (object->ref_count == 0) {
- queue_remove(&vm_object_cached_list, object,
- vm_object_t, cached_list);
- vm_object_cached_count--;
- vm_object_cached_pages_update(-object->resident_page_count);
- }
+ if (object->ref_count == 0)
+ vm_object_cache_remove(object);
object->ref_count++;
vm_object_unlock(object);
@@ -1872,12 +1889,8 @@ void vm_object_destroy(
object = (vm_object_t) pager->ip_kobject;
vm_object_lock(object);
- if (object->ref_count == 0) {
- queue_remove(&vm_object_cached_list, object,
- vm_object_t, cached_list);
- vm_object_cached_count--;
- vm_object_cached_pages_update(-object->resident_page_count);
- }
+ if (object->ref_count == 0)
+ vm_object_cache_remove(object);
object->ref_count++;
object->can_persist = FALSE;
@@ -2026,12 +2039,8 @@ restart:
if ((object != VM_OBJECT_NULL) && !must_init) {
vm_object_lock(object);
- if (object->ref_count == 0) {
- queue_remove(&vm_object_cached_list, object,
- vm_object_t, cached_list);
- vm_object_cached_count--;
- vm_object_cached_pages_update(-object->resident_page_count);
- }
+ if (object->ref_count == 0)
+ vm_object_cache_remove(object);
object->ref_count++;
vm_object_unlock(object);
@@ -2566,6 +2575,7 @@ void vm_object_collapse(
);
assert(backing_object->alive);
+ assert(!backing_object->cached);
backing_object->alive = FALSE;
vm_object_unlock(backing_object);
diff --git a/vm/vm_object.h b/vm/vm_object.h
index 9579879..6b9f0bc 100644
--- a/vm/vm_object.h
+++ b/vm/vm_object.h
@@ -148,8 +148,9 @@ struct vm_object {
*/
/* boolean_t */ use_shared_copy : 1,/* Use shared (i.e.,
* delayed) copy on write */
- /* boolean_t */ shadowed: 1; /* Shadow may exist */
+ /* boolean_t */ shadowed: 1, /* Shadow may exist */
+ /* boolean_t */ cached: 1; /* Object is cached */
queue_chain_t cached_list; /* Attachment point for the list
* of objects cached as a result
* of their can_persist value
--
2.1.4
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