/************************************************************************** * * 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 Hellstr�m <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); }