| /************************************************************************** |
| * |
| * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., 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. |
| * |
| * Aligned allocations can also see improvement. |
| * |
| * Authors: |
| * Thomas Hellström <thomas-at-tungstengraphics-dot-com> |
| */ |
| |
| #include "drmP.h" |
| #include <linux/slab.h> |
| |
| unsigned long drm_mm_tail_space(drm_mm_t *mm) |
| { |
| struct list_head *tail_node; |
| drm_mm_node_t *entry; |
| |
| tail_node = mm->ml_entry.prev; |
| entry = list_entry(tail_node, drm_mm_node_t, ml_entry); |
| if (!entry->free) |
| return 0; |
| |
| return entry->size; |
| } |
| |
| int drm_mm_remove_space_from_tail(drm_mm_t *mm, unsigned long size) |
| { |
| struct list_head *tail_node; |
| drm_mm_node_t *entry; |
| |
| tail_node = mm->ml_entry.prev; |
| entry = list_entry(tail_node, drm_mm_node_t, ml_entry); |
| if (!entry->free) |
| return -ENOMEM; |
| |
| if (entry->size <= size) |
| return -ENOMEM; |
| |
| entry->size -= size; |
| return 0; |
| } |
| |
| |
| static int drm_mm_create_tail_node(drm_mm_t *mm, |
| unsigned long start, |
| unsigned long size) |
| { |
| drm_mm_node_t *child; |
| |
| child = (drm_mm_node_t *) |
| drm_alloc(sizeof(*child), DRM_MEM_MM); |
| if (!child) |
| return -ENOMEM; |
| |
| child->free = 1; |
| child->size = size; |
| child->start = start; |
| child->mm = mm; |
| |
| list_add_tail(&child->ml_entry, &mm->ml_entry); |
| list_add_tail(&child->fl_entry, &mm->fl_entry); |
| |
| return 0; |
| } |
| |
| |
| int drm_mm_add_space_to_tail(drm_mm_t *mm, unsigned long size) |
| { |
| struct list_head *tail_node; |
| drm_mm_node_t *entry; |
| |
| tail_node = mm->ml_entry.prev; |
| entry = list_entry(tail_node, drm_mm_node_t, ml_entry); |
| if (!entry->free) { |
| return drm_mm_create_tail_node(mm, entry->start + entry->size, size); |
| } |
| entry->size += size; |
| return 0; |
| } |
| |
| static drm_mm_node_t *drm_mm_split_at_start(drm_mm_node_t *parent, |
| unsigned long size) |
| { |
| drm_mm_node_t *child; |
| |
| child = (drm_mm_node_t *) |
| drm_alloc(sizeof(*child), DRM_MEM_MM); |
| if (!child) |
| return NULL; |
| |
| INIT_LIST_HEAD(&child->fl_entry); |
| |
| child->free = 0; |
| child->size = size; |
| child->start = parent->start; |
| child->mm = parent->mm; |
| |
| list_add_tail(&child->ml_entry, &parent->ml_entry); |
| INIT_LIST_HEAD(&child->fl_entry); |
| |
| parent->size -= size; |
| parent->start += size; |
| return child; |
| } |
| |
| |
| |
| drm_mm_node_t *drm_mm_get_block(drm_mm_node_t * parent, |
| unsigned long size, unsigned alignment) |
| { |
| |
| drm_mm_node_t *align_splitoff = NULL; |
| drm_mm_node_t *child; |
| unsigned tmp = 0; |
| |
| if (alignment) |
| tmp = parent->start % alignment; |
| |
| if (tmp) { |
| align_splitoff = drm_mm_split_at_start(parent, alignment - tmp); |
| if (!align_splitoff) |
| return NULL; |
| } |
| |
| if (parent->size == size) { |
| list_del_init(&parent->fl_entry); |
| parent->free = 0; |
| return parent; |
| } else { |
| child = drm_mm_split_at_start(parent, size); |
| } |
| |
| if (align_splitoff) |
| drm_mm_put_block(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 drm_mm_put_block(drm_mm_node_t * cur) |
| { |
| |
| drm_mm_t *mm = cur->mm; |
| struct list_head *cur_head = &cur->ml_entry; |
| struct list_head *root_head = &mm->ml_entry; |
| drm_mm_node_t *prev_node = NULL; |
| drm_mm_node_t *next_node; |
| |
| int merged = 0; |
| |
| if (cur_head->prev != root_head) { |
| prev_node = list_entry(cur_head->prev, drm_mm_node_t, ml_entry); |
| if (prev_node->free) { |
| prev_node->size += cur->size; |
| merged = 1; |
| } |
| } |
| if (cur_head->next != root_head) { |
| next_node = list_entry(cur_head->next, drm_mm_node_t, ml_entry); |
| if (next_node->free) { |
| if (merged) { |
| prev_node->size += next_node->size; |
| list_del(&next_node->ml_entry); |
| list_del(&next_node->fl_entry); |
| drm_free(next_node, sizeof(*next_node), |
| DRM_MEM_MM); |
| } else { |
| next_node->size += cur->size; |
| next_node->start = cur->start; |
| merged = 1; |
| } |
| } |
| } |
| if (!merged) { |
| cur->free = 1; |
| list_add(&cur->fl_entry, &mm->fl_entry); |
| } else { |
| list_del(&cur->ml_entry); |
| drm_free(cur, sizeof(*cur), DRM_MEM_MM); |
| } |
| } |
| |
| drm_mm_node_t *drm_mm_search_free(const drm_mm_t * mm, |
| unsigned long size, |
| unsigned alignment, int best_match) |
| { |
| struct list_head *list; |
| const struct list_head *free_stack = &mm->fl_entry; |
| drm_mm_node_t *entry; |
| drm_mm_node_t *best; |
| unsigned long best_size; |
| unsigned wasted; |
| |
| best = NULL; |
| best_size = ~0UL; |
| |
| list_for_each(list, free_stack) { |
| entry = list_entry(list, drm_mm_node_t, 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 drm_mm_clean(drm_mm_t * mm) |
| { |
| struct list_head *head = &mm->ml_entry; |
| |
| return (head->next->next == head); |
| } |
| |
| int drm_mm_init(drm_mm_t * mm, unsigned long start, unsigned long size) |
| { |
| INIT_LIST_HEAD(&mm->ml_entry); |
| INIT_LIST_HEAD(&mm->fl_entry); |
| |
| return drm_mm_create_tail_node(mm, start, size); |
| } |
| |
| |
| void drm_mm_takedown(drm_mm_t * mm) |
| { |
| struct list_head *bnode = mm->fl_entry.next; |
| drm_mm_node_t *entry; |
| |
| entry = list_entry(bnode, drm_mm_node_t, fl_entry); |
| |
| if (entry->ml_entry.next != &mm->ml_entry || |
| entry->fl_entry.next != &mm->fl_entry) { |
| DRM_ERROR("Memory manager not clean. Delaying takedown\n"); |
| return; |
| } |
| |
| list_del(&entry->fl_entry); |
| list_del(&entry->ml_entry); |
| |
| drm_free(entry, sizeof(*entry), DRM_MEM_MM); |
| } |
| |