summaryrefslogtreecommitdiff
path: root/src/wsbm_mm.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/wsbm_mm.c')
-rw-r--r--src/wsbm_mm.c286
1 files changed, 286 insertions, 0 deletions
diff --git a/src/wsbm_mm.c b/src/wsbm_mm.c
new file mode 100644
index 0000000..e3c32fe
--- /dev/null
+++ b/src/wsbm_mm.c
@@ -0,0 +1,286 @@
+/**************************************************************************
+ *
+ * Copyright 2006-2008 Tungsten Graphics, Inc., Cedar Park, TX., USA.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ *
+ **************************************************************************/
+
+/*
+ * Generic simple memory manager implementation. Intended to be used as a base
+ * class implementation for more advanced memory managers.
+ *
+ * Note that the algorithm used is quite simple and there might be substantial
+ * performance gains if a smarter free list is implemented. Currently it is just an
+ * unordered stack of free regions. This could easily be improved if an RB-tree
+ * is used instead. At least if we expect heavy fragmentation.
+ *
+ * Authors:
+ * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "wsbm_mm.h"
+#include <errno.h>
+#include <stdlib.h>
+
+unsigned long
+wsbmMMTailSpace(struct _WsbmMM *mm)
+{
+ struct _WsbmListHead *tail_node;
+ struct _WsbmMMNode *entry;
+
+ tail_node = mm->ml_entry.prev;
+ entry = WSBMLISTENTRY(tail_node, struct _WsbmMMNode, ml_entry);
+
+ if (!entry->free)
+ return 0;
+
+ return entry->size;
+}
+
+int
+wsbmMMRemoveSpaceFromTail(struct _WsbmMM *mm, unsigned long size)
+{
+ struct _WsbmListHead *tail_node;
+ struct _WsbmMMNode *entry;
+
+ tail_node = mm->ml_entry.prev;
+ entry = WSBMLISTENTRY(tail_node, struct _WsbmMMNode, ml_entry);
+
+ if (!entry->free)
+ return -ENOMEM;
+
+ if (entry->size <= size)
+ return -ENOMEM;
+
+ entry->size -= size;
+ return 0;
+}
+
+static int
+wsbmMMCreateTailNode(struct _WsbmMM *mm,
+ unsigned long start, unsigned long size)
+{
+ struct _WsbmMMNode *child;
+
+ child = (struct _WsbmMMNode *)malloc(sizeof(*child));
+ if (!child)
+ return -ENOMEM;
+
+ child->free = 1;
+ child->size = size;
+ child->start = start;
+ child->mm = mm;
+
+ WSBMLISTADDTAIL(&child->ml_entry, &mm->ml_entry);
+ WSBMLISTADDTAIL(&child->fl_entry, &mm->fl_entry);
+
+ return 0;
+}
+
+static struct _WsbmMMNode *
+wsbmMMSplitAtStart(struct _WsbmMMNode *parent, unsigned long size)
+{
+ struct _WsbmMMNode *child;
+
+ child = (struct _WsbmMMNode *)malloc(sizeof(*child));
+ if (!child)
+ return NULL;
+
+ WSBMINITLISTHEAD(&child->fl_entry);
+
+ child->free = 0;
+ child->size = size;
+ child->start = parent->start;
+ child->mm = parent->mm;
+
+ WSBMLISTADDTAIL(&child->ml_entry, &parent->ml_entry);
+ WSBMINITLISTHEAD(&child->fl_entry);
+
+ parent->size -= size;
+ parent->start += size;
+ return child;
+}
+
+struct _WsbmMMNode *
+wsbmMMGetBlock(struct _WsbmMMNode *parent,
+ unsigned long size, unsigned alignment)
+{
+
+ struct _WsbmMMNode *align_splitoff = NULL;
+ struct _WsbmMMNode *child;
+ unsigned tmp = 0;
+
+ if (alignment)
+ tmp = parent->start % alignment;
+
+ if (tmp) {
+ align_splitoff = wsbmMMSplitAtStart(parent, alignment - tmp);
+ if (!align_splitoff)
+ return NULL;
+ }
+
+ if (parent->size == size) {
+ WSBMLISTDELINIT(&parent->fl_entry);
+ parent->free = 0;
+ return parent;
+ } else {
+ child = wsbmMMSplitAtStart(parent, size);
+ }
+
+ if (align_splitoff)
+ wsbmMMPutBlock(align_splitoff);
+
+ return child;
+}
+
+/*
+ * Put a block. Merge with the previous and / or next block if they are free.
+ * Otherwise add to the free stack.
+ */
+
+void
+wsbmMMPutBlock(struct _WsbmMMNode *cur)
+{
+
+ struct _WsbmMM *mm = cur->mm;
+ struct _WsbmListHead *cur_head = &cur->ml_entry;
+ struct _WsbmListHead *root_head = &mm->ml_entry;
+ struct _WsbmMMNode *prev_node = NULL;
+ struct _WsbmMMNode *next_node;
+
+ int merged = 0;
+
+ if (cur_head->prev != root_head) {
+ prev_node =
+ WSBMLISTENTRY(cur_head->prev, struct _WsbmMMNode, ml_entry);
+ if (prev_node->free) {
+ prev_node->size += cur->size;
+ merged = 1;
+ }
+ }
+ if (cur_head->next != root_head) {
+ next_node =
+ WSBMLISTENTRY(cur_head->next, struct _WsbmMMNode, ml_entry);
+ if (next_node->free) {
+ if (merged) {
+ prev_node->size += next_node->size;
+ WSBMLISTDEL(&next_node->ml_entry);
+ WSBMLISTDEL(&next_node->fl_entry);
+ free(next_node);
+ } else {
+ next_node->size += cur->size;
+ next_node->start = cur->start;
+ merged = 1;
+ }
+ }
+ }
+ if (!merged) {
+ cur->free = 1;
+ WSBMLISTADD(&cur->fl_entry, &mm->fl_entry);
+ } else {
+ WSBMLISTDEL(&cur->ml_entry);
+ free(cur);
+ }
+}
+
+struct _WsbmMMNode *
+wsbmMMSearchFree(const struct _WsbmMM *mm,
+ unsigned long size, unsigned alignment, int best_match)
+{
+ struct _WsbmListHead *list;
+ const struct _WsbmListHead *free_stack = &mm->fl_entry;
+ struct _WsbmMMNode *entry;
+ struct _WsbmMMNode *best;
+ unsigned long best_size;
+ unsigned wasted;
+
+ best = NULL;
+ best_size = ~0UL;
+
+ WSBMLISTFOREACH(list, free_stack) {
+ entry = WSBMLISTENTRY(list, struct _WsbmMMNode, fl_entry);
+
+ wasted = 0;
+
+ if (entry->size < size)
+ continue;
+
+ if (alignment) {
+ register unsigned tmp = entry->start % alignment;
+
+ if (tmp)
+ wasted += alignment - tmp;
+ }
+
+ if (entry->size >= size + wasted) {
+ if (!best_match)
+ return entry;
+ if (size < best_size) {
+ best = entry;
+ best_size = entry->size;
+ }
+ }
+ }
+
+ return best;
+}
+
+int
+wsbmMMclean(struct _WsbmMM *mm)
+{
+ struct _WsbmListHead *head = &mm->ml_entry;
+
+ return (head->next->next == head);
+}
+
+int
+wsbmMMinit(struct _WsbmMM *mm, unsigned long start, unsigned long size)
+{
+ WSBMINITLISTHEAD(&mm->ml_entry);
+ WSBMINITLISTHEAD(&mm->fl_entry);
+
+ return wsbmMMCreateTailNode(mm, start, size);
+}
+
+void
+wsbmMMtakedown(struct _WsbmMM *mm)
+{
+ struct _WsbmListHead *bnode = mm->fl_entry.next;
+ struct _WsbmMMNode *entry;
+
+ entry = WSBMLISTENTRY(bnode, struct _WsbmMMNode, fl_entry);
+
+ if (entry->ml_entry.next != &mm->ml_entry ||
+ entry->fl_entry.next != &mm->fl_entry) {
+ return;
+ }
+
+ WSBMLISTDEL(&entry->fl_entry);
+ WSBMLISTDEL(&entry->ml_entry);
+ free(entry);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-10 00:11:52 +0000