linux/drivers/gpu/drm/drm_mm.c
Daniel Vetter 709ea97145 drm: implement helper functions for scanning lru list
These helper functions can be used to efficiently scan lru list
for eviction. Eviction becomes a three stage process:
1. Scanning through the lru list until a suitable hole has been found.
2. Scan backwards to restore drm_mm consistency and find out which
   objects fall into the hole.
3. Evict the objects that fall into the hole.

These helper functions don't allocate any memory (at the price of
not allowing any other concurrent operations). Hence this can also be
used for ttm (which does lru scanning under a spinlock).

Evicting objects in this fashion should be more fair than the current
approach by i915 (scan the lru for a object large enough to contain
the new object). It's also more efficient than the current approach used
by ttm (uncoditionally evict objects from the lru until there's enough
free space).

Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Thomas Hellstrom <thellstrom@vmwgfx.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-07-07 12:29:51 +10:00

617 lines
15 KiB
C

/**************************************************************************
*
* 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>
#include <linux/seq_file.h>
#define MM_UNUSED_TARGET 4
static struct drm_mm_node *drm_mm_kmalloc(struct drm_mm *mm, int atomic)
{
struct drm_mm_node *child;
if (atomic)
child = kzalloc(sizeof(*child), GFP_ATOMIC);
else
child = kzalloc(sizeof(*child), GFP_KERNEL);
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, free_stack);
list_del(&child->free_stack);
--mm->num_unused;
}
spin_unlock(&mm->unused_lock);
}
return child;
}
/* drm_mm_pre_get() - pre allocate drm_mm_node structure
* drm_mm: memory manager struct we are pre-allocating for
*
* Returns 0 on success or -ENOMEM if allocation fails.
*/
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 = kzalloc(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->free_stack, &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->node_list, &mm->node_list);
list_add_tail(&child->free_stack, &mm->free_stack);
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->free_stack);
child->size = size;
child->start = parent->start;
child->mm = parent->mm;
list_add_tail(&child->node_list, &parent->node_list);
INIT_LIST_HEAD(&child->free_stack);
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->free_stack);
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);
struct drm_mm_node *drm_mm_get_block_range_generic(struct drm_mm_node *node,
unsigned long size,
unsigned alignment,
unsigned long start,
unsigned long end,
int atomic)
{
struct drm_mm_node *align_splitoff = NULL;
unsigned tmp = 0;
unsigned wasted = 0;
if (node->start < start)
wasted += start - node->start;
if (alignment)
tmp = ((node->start + wasted) % alignment);
if (tmp)
wasted += alignment - tmp;
if (wasted) {
align_splitoff = drm_mm_split_at_start(node, wasted, atomic);
if (unlikely(align_splitoff == NULL))
return NULL;
}
if (node->size == size) {
list_del_init(&node->free_stack);
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_range_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->node_list;
struct list_head *root_head = &mm->node_list;
struct drm_mm_node *prev_node = NULL;
struct drm_mm_node *next_node;
int merged = 0;
BUG_ON(cur->scanned_block || cur->scanned_prev_free
|| cur->scanned_next_free);
if (cur_head->prev != root_head) {
prev_node =
list_entry(cur_head->prev, struct drm_mm_node, node_list);
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, node_list);
if (next_node->free) {
if (merged) {
prev_node->size += next_node->size;
list_del(&next_node->node_list);
list_del(&next_node->free_stack);
spin_lock(&mm->unused_lock);
if (mm->num_unused < MM_UNUSED_TARGET) {
list_add(&next_node->free_stack,
&mm->unused_nodes);
++mm->num_unused;
} else
kfree(next_node);
spin_unlock(&mm->unused_lock);
} else {
next_node->size += cur->size;
next_node->start = cur->start;
merged = 1;
}
}
}
if (!merged) {
cur->free = 1;
list_add(&cur->free_stack, &mm->free_stack);
} else {
list_del(&cur->node_list);
spin_lock(&mm->unused_lock);
if (mm->num_unused < MM_UNUSED_TARGET) {
list_add(&cur->free_stack, &mm->unused_nodes);
++mm->num_unused;
} else
kfree(cur);
spin_unlock(&mm->unused_lock);
}
}
EXPORT_SYMBOL(drm_mm_put_block);
static int check_free_mm_node(struct drm_mm_node *entry, unsigned long size,
unsigned alignment)
{
unsigned wasted = 0;
if (entry->size < size)
return 0;
if (alignment) {
register unsigned tmp = entry->start % alignment;
if (tmp)
wasted = alignment - tmp;
}
if (entry->size >= size + wasted) {
return 1;
}
return 0;
}
struct drm_mm_node *drm_mm_search_free(const struct drm_mm *mm,
unsigned long size,
unsigned alignment, int best_match)
{
struct drm_mm_node *entry;
struct drm_mm_node *best;
unsigned long best_size;
BUG_ON(mm->scanned_blocks);
best = NULL;
best_size = ~0UL;
list_for_each_entry(entry, &mm->free_stack, free_stack) {
if (!check_free_mm_node(entry, size, alignment))
continue;
if (!best_match)
return entry;
if (entry->size < best_size) {
best = entry;
best_size = entry->size;
}
}
return best;
}
EXPORT_SYMBOL(drm_mm_search_free);
struct drm_mm_node *drm_mm_search_free_in_range(const struct drm_mm *mm,
unsigned long size,
unsigned alignment,
unsigned long start,
unsigned long end,
int best_match)
{
struct drm_mm_node *entry;
struct drm_mm_node *best;
unsigned long best_size;
BUG_ON(mm->scanned_blocks);
best = NULL;
best_size = ~0UL;
list_for_each_entry(entry, &mm->free_stack, free_stack) {
if (entry->start > end || (entry->start+entry->size) < start)
continue;
if (!check_free_mm_node(entry, size, alignment))
continue;
if (!best_match)
return entry;
if (entry->size < best_size) {
best = entry;
best_size = entry->size;
}
}
return best;
}
EXPORT_SYMBOL(drm_mm_search_free_in_range);
/**
* Initializa lru scanning.
*
* This simply sets up the scanning routines with the parameters for the desired
* hole.
*
* Warning: As long as the scan list is non-empty, no other operations than
* adding/removing nodes to/from the scan list are allowed.
*/
void drm_mm_init_scan(struct drm_mm *mm, unsigned long size,
unsigned alignment)
{
mm->scan_alignment = alignment;
mm->scan_size = size;
mm->scanned_blocks = 0;
mm->scan_hit_start = 0;
mm->scan_hit_size = 0;
}
EXPORT_SYMBOL(drm_mm_init_scan);
/**
* Add a node to the scan list that might be freed to make space for the desired
* hole.
*
* Returns non-zero, if a hole has been found, zero otherwise.
*/
int drm_mm_scan_add_block(struct drm_mm_node *node)
{
struct drm_mm *mm = node->mm;
struct list_head *prev_free, *next_free;
struct drm_mm_node *prev_node, *next_node;
mm->scanned_blocks++;
prev_free = next_free = NULL;
BUG_ON(node->free);
node->scanned_block = 1;
node->free = 1;
if (node->node_list.prev != &mm->node_list) {
prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
node_list);
if (prev_node->free) {
list_del(&prev_node->node_list);
node->start = prev_node->start;
node->size += prev_node->size;
prev_node->scanned_prev_free = 1;
prev_free = &prev_node->free_stack;
}
}
if (node->node_list.next != &mm->node_list) {
next_node = list_entry(node->node_list.next, struct drm_mm_node,
node_list);
if (next_node->free) {
list_del(&next_node->node_list);
node->size += next_node->size;
next_node->scanned_next_free = 1;
next_free = &next_node->free_stack;
}
}
/* The free_stack list is not used for allocated objects, so these two
* pointers can be abused (as long as no allocations in this memory
* manager happens). */
node->free_stack.prev = prev_free;
node->free_stack.next = next_free;
if (check_free_mm_node(node, mm->scan_size, mm->scan_alignment)) {
mm->scan_hit_start = node->start;
mm->scan_hit_size = node->size;
return 1;
}
return 0;
}
EXPORT_SYMBOL(drm_mm_scan_add_block);
/**
* Remove a node from the scan list.
*
* Nodes _must_ be removed in the exact same order from the scan list as they
* have been added, otherwise the internal state of the memory manager will be
* corrupted.
*
* When the scan list is empty, the selected memory nodes can be freed. An
* immediatly following drm_mm_search_free with best_match = 0 will then return
* the just freed block (because its at the top of the free_stack list).
*
* Returns one if this block should be evicted, zero otherwise. Will always
* return zero when no hole has been found.
*/
int drm_mm_scan_remove_block(struct drm_mm_node *node)
{
struct drm_mm *mm = node->mm;
struct drm_mm_node *prev_node, *next_node;
mm->scanned_blocks--;
BUG_ON(!node->scanned_block);
node->scanned_block = 0;
node->free = 0;
prev_node = list_entry(node->free_stack.prev, struct drm_mm_node,
free_stack);
next_node = list_entry(node->free_stack.next, struct drm_mm_node,
free_stack);
if (prev_node) {
BUG_ON(!prev_node->scanned_prev_free);
prev_node->scanned_prev_free = 0;
list_add_tail(&prev_node->node_list, &node->node_list);
node->start = prev_node->start + prev_node->size;
node->size -= prev_node->size;
}
if (next_node) {
BUG_ON(!next_node->scanned_next_free);
next_node->scanned_next_free = 0;
list_add(&next_node->node_list, &node->node_list);
node->size -= next_node->size;
}
INIT_LIST_HEAD(&node->free_stack);
/* Only need to check for containement because start&size for the
* complete resulting free block (not just the desired part) is
* stored. */
if (node->start >= mm->scan_hit_start &&
node->start + node->size
<= mm->scan_hit_start + mm->scan_hit_size) {
return 1;
}
return 0;
}
EXPORT_SYMBOL(drm_mm_scan_remove_block);
int drm_mm_clean(struct drm_mm * mm)
{
struct list_head *head = &mm->node_list;
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->node_list);
INIT_LIST_HEAD(&mm->free_stack);
INIT_LIST_HEAD(&mm->unused_nodes);
mm->num_unused = 0;
mm->scanned_blocks = 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->free_stack.next;
struct drm_mm_node *entry;
struct drm_mm_node *next;
entry = list_entry(bnode, struct drm_mm_node, free_stack);
if (entry->node_list.next != &mm->node_list ||
entry->free_stack.next != &mm->free_stack) {
DRM_ERROR("Memory manager not clean. Delaying takedown\n");
return;
}
list_del(&entry->free_stack);
list_del(&entry->node_list);
kfree(entry);
spin_lock(&mm->unused_lock);
list_for_each_entry_safe(entry, next, &mm->unused_nodes, free_stack) {
list_del(&entry->free_stack);
kfree(entry);
--mm->num_unused;
}
spin_unlock(&mm->unused_lock);
BUG_ON(mm->num_unused != 0);
}
EXPORT_SYMBOL(drm_mm_takedown);
void drm_mm_debug_table(struct drm_mm *mm, const char *prefix)
{
struct drm_mm_node *entry;
int total_used = 0, total_free = 0, total = 0;
list_for_each_entry(entry, &mm->node_list, node_list) {
printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8ld: %s\n",
prefix, entry->start, entry->start + entry->size,
entry->size, entry->free ? "free" : "used");
total += entry->size;
if (entry->free)
total_free += entry->size;
else
total_used += entry->size;
}
printk(KERN_DEBUG "%s total: %d, used %d free %d\n", prefix, total,
total_used, total_free);
}
EXPORT_SYMBOL(drm_mm_debug_table);
#if defined(CONFIG_DEBUG_FS)
int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm)
{
struct drm_mm_node *entry;
int total_used = 0, total_free = 0, total = 0;
list_for_each_entry(entry, &mm->node_list, node_list) {
seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: %s\n", entry->start, entry->start + entry->size, entry->size, entry->free ? "free" : "used");
total += entry->size;
if (entry->free)
total_free += entry->size;
else
total_used += entry->size;
}
seq_printf(m, "total: %d, used %d free %d\n", total, total_used, total_free);
return 0;
}
EXPORT_SYMBOL(drm_mm_dump_table);
#endif