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/************************************************************************** |
* |
* 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 "drm_mm.h" |
//#include <linux/slab.h> |
|
#define MM_UNUSED_TARGET 4 |
|
unsigned long drm_mm_tail_space(struct drm_mm *mm) |
{ |
struct list_head *tail_node; |
struct drm_mm_node *entry; |
|
tail_node = mm->ml_entry.prev; |
entry = list_entry(tail_node, struct drm_mm_node, ml_entry); |
if (!entry->free) |
return 0; |
|
return entry->size; |
} |
|
int drm_mm_remove_space_from_tail(struct drm_mm *mm, unsigned long size) |
{ |
struct list_head *tail_node; |
struct drm_mm_node *entry; |
|
tail_node = mm->ml_entry.prev; |
entry = list_entry(tail_node, struct drm_mm_node, ml_entry); |
if (!entry->free) |
return -ENOMEM; |
|
if (entry->size <= size) |
return -ENOMEM; |
|
entry->size -= size; |
return 0; |
} |
|
static struct drm_mm_node *drm_mm_kmalloc(struct drm_mm *mm, int atomic) |
{ |
struct drm_mm_node *child; |
|
child = malloc(sizeof(*child)); |
|
if (unlikely(child == NULL)) { |
spin_lock(&mm->unused_lock); |
if (list_empty(&mm->unused_nodes)) |
child = NULL; |
else { |
child = |
list_entry(mm->unused_nodes.next, |
struct drm_mm_node, fl_entry); |
list_del(&child->fl_entry); |
--mm->num_unused; |
} |
spin_unlock(&mm->unused_lock); |
} |
return child; |
} |
|
int drm_mm_pre_get(struct drm_mm *mm) |
{ |
struct drm_mm_node *node; |
|
spin_lock(&mm->unused_lock); |
while (mm->num_unused < MM_UNUSED_TARGET) { |
spin_unlock(&mm->unused_lock); |
node = kmalloc(sizeof(*node), GFP_KERNEL); |
spin_lock(&mm->unused_lock); |
|
if (unlikely(node == NULL)) { |
int ret = (mm->num_unused < 2) ? -ENOMEM : 0; |
spin_unlock(&mm->unused_lock); |
return ret; |
} |
++mm->num_unused; |
list_add_tail(&node->fl_entry, &mm->unused_nodes); |
} |
spin_unlock(&mm->unused_lock); |
return 0; |
} |
//EXPORT_SYMBOL(drm_mm_pre_get); |
|
static int drm_mm_create_tail_node(struct drm_mm *mm, |
unsigned long start, |
unsigned long size, int atomic) |
{ |
struct drm_mm_node *child; |
|
child = drm_mm_kmalloc(mm, atomic); |
if (unlikely(child == NULL)) |
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(struct drm_mm *mm, unsigned long size, int atomic) |
{ |
struct list_head *tail_node; |
struct drm_mm_node *entry; |
|
tail_node = mm->ml_entry.prev; |
entry = list_entry(tail_node, struct drm_mm_node, ml_entry); |
if (!entry->free) { |
return drm_mm_create_tail_node(mm, entry->start + entry->size, |
size, atomic); |
} |
entry->size += size; |
return 0; |
} |
|
static struct drm_mm_node *drm_mm_split_at_start(struct drm_mm_node *parent, |
unsigned long size, |
int atomic) |
{ |
struct drm_mm_node *child; |
|
child = drm_mm_kmalloc(parent->mm, atomic); |
if (unlikely(child == NULL)) |
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; |
} |
|
|
struct drm_mm_node *drm_mm_get_block_generic(struct drm_mm_node *node, |
unsigned long size, |
unsigned alignment, |
int atomic) |
{ |
|
struct drm_mm_node *align_splitoff = NULL; |
unsigned tmp = 0; |
|
if (alignment) |
tmp = node->start % alignment; |
|
if (tmp) { |
align_splitoff = |
drm_mm_split_at_start(node, alignment - tmp, atomic); |
if (unlikely(align_splitoff == NULL)) |
return NULL; |
} |
|
if (node->size == size) { |
list_del_init(&node->fl_entry); |
node->free = 0; |
} else { |
node = drm_mm_split_at_start(node, size, atomic); |
} |
|
if (align_splitoff) |
drm_mm_put_block(align_splitoff); |
|
return node; |
} |
//EXPORT_SYMBOL(drm_mm_get_block_generic); |
|
/* |
* 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(struct drm_mm_node *cur) |
{ |
|
struct drm_mm *mm = cur->mm; |
struct list_head *cur_head = &cur->ml_entry; |
struct list_head *root_head = &mm->ml_entry; |
struct drm_mm_node *prev_node = NULL; |
struct drm_mm_node *next_node; |
|
int merged = 0; |
|
if (cur_head->prev != root_head) { |
prev_node = |
list_entry(cur_head->prev, struct drm_mm_node, 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, struct drm_mm_node, 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); |
if (mm->num_unused < MM_UNUSED_TARGET) { |
list_add(&next_node->fl_entry, |
&mm->unused_nodes); |
++mm->num_unused; |
} else |
kfree(next_node); |
} 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); |
if (mm->num_unused < MM_UNUSED_TARGET) { |
list_add(&cur->fl_entry, &mm->unused_nodes); |
++mm->num_unused; |
} else |
kfree(cur); |
} |
} |
|
//EXPORT_SYMBOL(drm_mm_put_block); |
|
struct drm_mm_node *drm_mm_search_free(const struct drm_mm *mm, |
unsigned long size, |
unsigned alignment, int best_match) |
{ |
struct list_head *list; |
const struct list_head *free_stack = &mm->fl_entry; |
struct drm_mm_node *entry; |
struct drm_mm_node *best; |
unsigned long best_size; |
unsigned wasted; |
|
best = NULL; |
best_size = ~0UL; |
|
list_for_each(list, free_stack) { |
entry = list_entry(list, struct drm_mm_node, 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; |
} |
//EXPORT_SYMBOL(drm_mm_search_free); |
|
int drm_mm_clean(struct drm_mm * mm) |
{ |
struct list_head *head = &mm->ml_entry; |
|
return (head->next->next == head); |
} |
//EXPORT_SYMBOL(drm_mm_clean); |
|
int drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size) |
{ |
INIT_LIST_HEAD(&mm->ml_entry); |
INIT_LIST_HEAD(&mm->fl_entry); |
INIT_LIST_HEAD(&mm->unused_nodes); |
mm->num_unused = 0; |
spin_lock_init(&mm->unused_lock); |
|
return drm_mm_create_tail_node(mm, start, size, 0); |
} |
//EXPORT_SYMBOL(drm_mm_init); |
|
void drm_mm_takedown(struct drm_mm * mm) |
{ |
struct list_head *bnode = mm->fl_entry.next; |
struct drm_mm_node *entry; |
struct drm_mm_node *next; |
|
entry = list_entry(bnode, struct drm_mm_node, 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); |
kfree(entry); |
|
spin_lock(&mm->unused_lock); |
list_for_each_entry_safe(entry, next, &mm->unused_nodes, fl_entry) { |
list_del(&entry->fl_entry); |
kfree(entry); |
--mm->num_unused; |
} |
spin_unlock(&mm->unused_lock); |
|
BUG_ON(mm->num_unused != 0); |
} |
//EXPORT_SYMBOL(drm_mm_takedown); |