ref: 3f8b7b23999b672f2aac922c9c1ba04e32628396
parent: e4681dd485de5a393070e3fcb91505116405cc1d
author: Simon Howard <fraggle@gmail.com>
date: Sun Jul 29 20:31:33 EDT 2007
Fix bug in z_native linked list logic. Clear out all PU_CACHE blocks when out of memory. Subversion-branch: /trunk/chocolate-doom Subversion-revision: 940
--- a/src/z_native.c
+++ b/src/z_native.c
@@ -42,6 +42,7 @@
{int id; // = ZONEID
int tag;
+ int size;
void **user;
memblock_t *prev;
memblock_t *next;
@@ -51,6 +52,45 @@
static memblock_t *allocated_blocks[PU_NUM_TAGS];
+#ifdef TESTING
+
+static int test_malloced = 0;
+
+void *test_malloc(size_t size)
+{+ int *result;
+
+ if (test_malloced + size > 2 * 1024 * 1024)
+ {+ return NULL;
+ }
+
+ test_malloced += size;
+
+ result = malloc(size + sizeof(int));
+
+ *result = size;
+
+ return result + 1;
+}
+
+void test_free(void *data)
+{+ int *i;
+
+ i = ((int *) data) - 1;
+
+ test_malloced -= *i;
+
+ free(i);
+}
+
+#define malloc test_malloc
+#define free test_free
+
+#endif /* #ifdef TESTING */
+
+
// Add a block into the linked list for its type.
static void Z_InsertBlock(memblock_t *block)
@@ -57,7 +97,7 @@
{block->prev = NULL;
block->next = allocated_blocks[block->tag];
- allocated_blocks[block->tag] = block->next;
+ allocated_blocks[block->tag] = block;
if (block->next != NULL)
{@@ -108,7 +148,9 @@
block = (memblock_t *) ((byte *)ptr - sizeof(memblock_t));
if (block->id != ZONEID)
+ { I_Error ("Z_Free: freed a pointer without ZONEID");+ }
if (block->tag != PU_FREE && block->user != NULL)
{@@ -124,8 +166,70 @@
free(block);
}
+// Empty data from the cache list to allocate enough data of the size
+// required.
+//
+// Returns true if any blocks were freed.
+static boolean ClearCache(int size)
+{+ memblock_t *block;
+ memblock_t *next_block;
+ int remaining;
+ block = allocated_blocks[PU_CACHE];
+
+ if (block == NULL)
+ {+ // Cache is already empty.
+
+ return false;
+ }
+
+ // Search to the end of the PU_CACHE list. The blocks at the end
+ // of the list are the ones that have been free for longer and
+ // are more likely to be unneeded now.
+
+ while (block->next != NULL)
+ {+ block = block->next;
+ }
+
+ //printf("out of memory; cleaning out the cache: %i\n", test_malloced);+
+ // Search backwards through the list freeing blocks until we have
+ // freed the amount of memory required.
+
+ remaining = size;
+
+ while (remaining > 0)
+ {+ if (block == NULL)
+ {+ // No blocks left to free; we've done our best.
+
+ break;
+ }
+
+ next_block = block->prev;
+
+ Z_RemoveBlock(block);
+
+ remaining -= block->size;
+
+ if (block->user)
+ {+ *block->user = NULL;
+ }
+
+ free(block);
+
+ block = next_block;
+ }
+
+ return true;
+}
+
//
// Z_Malloc
// You can pass a NULL user if the tag is < PU_PURGELEVEL.
@@ -144,9 +248,27 @@
}
if (user == NULL && tag >= PU_PURGELEVEL)
+ { I_Error ("Z_Malloc: an owner is required for purgable blocks");+ }
+
+ // Malloc a block of the required size
- newblock = (memblock_t *) malloc(sizeof(memblock_t) + size);
+ newblock = NULL;
+
+ while (newblock == NULL)
+ {+ newblock = (memblock_t *) malloc(sizeof(memblock_t) + size);
+
+ if (newblock == NULL)
+ {+ if (!ClearCache(sizeof(memblock_t) + size))
+ {+ I_Error("Out of memory!");+ }
+ }
+ }
+
newblock->tag = tag;
// Hook into the linked list for this tag type
@@ -153,6 +275,7 @@
newblock->id = ZONEID;
newblock->user = user;
+ newblock->size = size;
Z_InsertBlock(newblock);