| /************************************************************************** |
| * |
| * Copyright 2006-2008 Tungsten Graphics, Inc., Cedar Park, TX., USA. |
| * All Rights Reserved. |
| * Copyright 2009 VMware, Inc., Palo Alto, CA., 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. |
| * Note that this implementation is more or less identical to the drm core manager |
| * in the linux kernel. |
| * |
| * 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); |
| } |