/**************************************************************************
*
* Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA.
* Copyright 2016 Intel Corporation
* 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 <linux/export.h>
#include <linux/interval_tree_generic.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/stacktrace.h>
#include <drm/drm_mm.h>
/**
* DOC: Overview
*
* drm_mm provides a simple range allocator. The drivers are free to use the
* resource allocator from the linux core if it suits them, the upside of drm_mm
* is that it's in the DRM core. Which means that it's easier to extend for
* some of the crazier special purpose needs of gpus.
*
* The main data struct is &drm_mm, allocations are tracked in &drm_mm_node.
* Drivers are free to embed either of them into their own suitable
* datastructures. drm_mm itself will not do any memory allocations of its own,
* so if drivers choose not to embed nodes they need to still allocate them
* themselves.
*
* The range allocator also supports reservation of preallocated blocks. This is
* useful for taking over initial mode setting configurations from the firmware,
* where an object needs to be created which exactly matches the firmware's
* scanout target. As long as the range is still free it can be inserted anytime
* after the allocator is initialized, which helps with avoiding looped
* dependencies in the driver load sequence.
*
* drm_mm maintains a stack of most recently freed holes, which of all
* simplistic datastructures seems to be a fairly decent approach to clustering
* allocations and avoiding too much fragmentation. This means free space
* searches are O(num_holes). Given that all the fancy features drm_mm supports
* something better would be fairly complex and since gfx thrashing is a fairly
* steep cliff not a real concern. Removing a node again is O(1).
*
* drm_mm supports a few features: Alignment and range restrictions can be
* supplied. Furthermore every &drm_mm_node has a color value (which is just an
* opaque unsigned long) which in conjunction with a driver callback can be used
* to implement sophisticated placement restrictions. The i915 DRM driver uses
* this to implement guard pages between incompatible caching domains in the
* graphics TT.
*
* Two behaviors are supported for searching and allocating: bottom-up and
* top-down. The default is bottom-up. Top-down allocation can be used if the
* memory area has different restrictions, or just to reduce fragmentation.
*
* Finally iteration helpers to walk all nodes and all holes are provided as are
* some basic allocator dumpers for debugging.
*
* Note that this range allocator is not thread-safe, drivers need to protect
* modifications with their own locking. The idea behind this is that for a full
* memory manager additional data needs to be protected anyway, hence internal
* locking would be fully redundant.
*/
#ifdef CONFIG_DRM_DEBUG_MM
#include <linux/stackdepot.h>
#define STACKDEPTH 32
#define BUFSZ 4096
static noinline void save_stack(struct drm_mm_node *node)
{
unsigned long entries[STACKDEPTH];
unsigned int n;
n = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
/* May be called under spinlock, so avoid sleeping */
node->stack = stack_depot_save(entries, n, GFP_NOWAIT);
}
static void show_leaks(struct drm_mm *mm)
{
struct drm_mm_node *node;
char *buf;
buf = kmalloc(BUFSZ, GFP_KERNEL);
if (!buf)
return;
list_for_each_entry(node, drm_mm_nodes(mm), node_list) {
if (!node->stack) {
DRM_ERROR("node [%08llx + %08llx]: unknown owner\n",
node->start, node->size);
continue;
}
stack_depot_snprint(node->stack, buf, BUFSZ, 0);
DRM_ERROR("node [%08llx + %08llx]: inserted at\n%s",
node->start, node->size, buf);
}
kfree(buf);
}
#undef STACKDEPTH
#undef BUFSZ
#else
static void save_stack(struct drm_mm_node *node) { }
static void show_leaks(struct drm_mm *mm) { }
#endif
#define START(node) ((node)->start)
#define LAST(node) ((node)->start + (node)->size - 1)
INTERVAL_TREE_DEFINE(struct drm_mm_node, rb,
u64, __subtree_last,
START, LAST, static inline, drm_mm_interval_tree)
struct drm_mm_node *
__drm_mm_interval_first(const struct drm_mm *mm, u64 start, u64 last)
{
return drm_mm_interval_tree_iter_first((struct rb_root_cached *)&mm->interval_tree,
start, last) ?: (struct drm_mm_node *)&mm->head_node;
}
EXPORT_SYMBOL(__drm_mm_interval_first);
static void drm_mm_interval_tree_add_node(struct drm_mm_node *hole_node,
struct drm_mm_node *node)
{
struct drm_mm *mm = hole_node->mm;
struct rb_node **link, *rb;
struct drm_mm_node *parent;
bool leftmost;
node->__subtree_last = LAST(node);
if (drm_mm_node_allocated(hole_node)) {
rb = &hole_node->rb;
while (rb) {
parent = rb_entry(rb, struct drm_mm_node, rb);
if (parent->__subtree_last >= node->__subtree_last)
break;
parent->__subtree_last = node->__subtree_last;
rb = rb_parent(rb);
}
rb = &hole_node->rb;
link = &hole_node->rb.rb_right;
leftmost = false;
} else {
rb = NULL;
link = &mm->interval_tree.rb_root.rb_node;
leftmost = true;
}
while (*link) {
rb = *link;
parent = rb_entry(rb, struct drm_mm_node, rb);
if (parent->__subtree_last < node->__subtree_last)
parent->__subtree_last = node->__subtree_last;
if (node->start < parent->start) {
link = &parent->rb.rb_left;
} else {
link = &parent->rb.rb_right;
leftmost = false;
}
}
rb_link_node(&node->rb, rb, link);
rb_insert_augmented_cached(&node->rb, &mm->interval_tree, leftmost,
&drm_mm_interval_tree_augment);
}
#define HOLE_SIZE(NODE) ((NODE)->hole_size)
#define HOLE_ADDR(NODE) (__drm_mm_hole_node_start(NODE))
static u64 rb_to_hole_size(struct rb_node *rb)
{
return rb_entry(rb, struct drm_mm_node, rb_hole_size)->hole_size;
}
static void insert_hole_size(struct rb_root_cached *root,
struct drm_mm_node *node)
{
struct rb_node **link = &root->rb_root.rb_node, *rb = NULL;
u64 x = node->hole_size;
bool first = true;
while (*link) {
rb = *link;
if (x > rb_to_hole_size(rb)) {
link = &rb->rb_left;
} else {
link = &rb->rb_right;
first = false;
}
}
rb_link_node(&node->rb_hole_size, rb, link);
rb_insert_color_cached(&node->rb_hole_size, root, first);
}
RB_DECLARE_CALLBACKS_MAX(static, augment_callbacks,
struct drm_mm_node, rb_hole_addr,
u64, subtree_max_hole, HOLE_SIZE)
static void insert_hole_addr(struct rb_root *root, struct drm_mm_node *node)
{
struct rb_node **link = &root->rb_node, *rb_parent = NULL;
u64 start = HOLE_ADDR(node), subtree_max_hole = node->subtree_max_hole;
struct drm_mm_node *parent;
while (*link) {
rb_parent = *link;
parent = rb_entry(rb_parent, struct drm_mm_node, rb_hole_addr);
if (parent->subtree_max_hole < subtree_max_hole)
parent->subtree_max_hole = subtree_max_hole;
if (start < HOLE_ADDR(parent))
link = &parent->rb_hole_addr.rb_left;
else
link = &parent->rb_hole_addr.rb_right;
}
rb_link_node(&node->rb_hole_addr, rb_parent, link);
rb_insert_augmented(&node->rb_hole_addr, root, &augment_callbacks);
}
static void add_hole(struct drm_mm_node *node)
{
struct drm_mm *mm = node->mm;
node->hole_size =
__drm_mm_hole_node_end(node) - __drm_mm_hole_node_start(node);
node->subtree_max_hole = node->hole_size;
DRM_MM_BUG_ON(!drm_mm_hole_follows(node));
insert_hole_size(&mm->holes_size, node);
insert_hole_addr(&mm->holes_addr, node);
list_add(&node->hole_stack, &mm->hole_stack);
}
static void rm_hole(struct drm_mm_node *node)
{
DRM_MM_BUG_ON(!drm_mm_hole_follows(node));
list_del(&node->hole_stack);
rb_erase_cached(&node->rb_hole_size, &node->mm->holes_size);
rb_erase_augmented(&node->rb_hole_addr, &node->mm->holes_addr,
&augment_callbacks);
node->hole_size = 0;
node->subtree_max_hole = 0;
DRM_MM_BUG_ON(drm_mm_hole_follows(node));
}
static inline struct drm_mm_node *rb_hole_size_to_node(struct rb_node *rb)
{
return rb_entry_safe(rb, struct drm_mm_node, rb_hole_size);
}
static inline struct drm_mm_node *rb_hole_addr_to_node(struct rb_node *rb)
{
return rb_entry_safe(rb, struct drm_mm_node, rb_hole_addr);
}
static struct drm_mm_node *best_hole(struct drm_mm *mm, u64 size)
{
struct rb_node *rb = mm->holes_size.rb_root.rb_node;
struct drm_mm_node *best = NULL;
do {
struct drm_mm_node *node =
rb_entry(rb, struct drm_mm_node, rb_hole_size);
if (size <= node->hole_size) {
best = node;
rb = rb->rb_right;
} else {
rb = rb->rb_left;
}
} while (rb);
return best;
}
static bool usable_hole_addr(struct rb_node *rb, u64 size)
{
return rb && rb_hole_addr_to_node(rb)->subtree_max_hole >= size;
}
static struct drm_mm_node *find_hole_addr(struct drm_mm *mm, u64 addr, u64 size)
{
struct rb_node *rb = mm->holes_addr.rb_node;
struct drm_mm_node *node = NULL;
while (rb) {
u64 hole_start;
if (!usable_hole_addr(rb, size))
break;
node = rb_hole_addr_to_node(rb);
hole_start = __drm_mm_hole_node_start(node);
if (addr < hole_start)
rb = node->rb_hole_addr.rb_left;
else if (addr > hole_start + node->hole_size)
rb = node->rb_hole_addr.rb_right;
else
break;
}
return node;
}
static struct drm_mm_node *
first_hole(struct drm_mm *mm,
u64 start, u64 end, u64 size,
enum drm_mm_insert_mode mode)
{
switch (mode) {
default:
case DRM_MM_INSERT_BEST:
return best_hole(mm, size);
case DRM_MM_INSERT_LOW:
return find_hole_addr(mm, start, size);
case DRM_MM_INSERT_HIGH:
return find_hole_addr(mm, end, size);
case DRM_MM_INSERT_EVICT:
return list_first_entry_or_null(&mm->hole_stack,
struct drm_mm_node,
hole_stack);
}
}
/**
* DECLARE_NEXT_HOLE_ADDR - macro to declare next hole functions
* @name: name of function to declare
* @first: first rb member to traverse (either rb_left or rb_right).
* @last: last rb member to traverse (either rb_right or rb_left).
*
* This macro declares a function to return the next hole of the addr rb tree.
* While traversing the tree we take the searched size into account and only
* visit branches with potential big enough holes.
*/
#define DECLARE_NEXT_HOLE_ADDR(name, first, last) \
static struct drm_mm_node *name(struct drm_mm_node *entry, u64 size) \
{ \
struct rb_node *parent, *node = &entry->rb_hole_addr; \
\
if (!entry || RB_EMPTY_NODE(node)) \
return NULL; \
\
if (usable_hole_addr(node->first, size)) { \
node = node->first; \
while (usable_hole_addr(node->last, size)) \
node = node->last; \
return rb_hole_addr_to_node(node); \
} \
\
while ((parent = rb_parent(node)) && node == parent->first) \
node = parent; \
\
return rb_hole_addr_to_node(parent); \
}
DECLARE_NEXT_HOLE_ADDR(next_hole_high_addr, rb_left, rb_right)
DECLARE_NEXT_HOLE_ADDR(next_hole_low_addr, rb_right, rb_left)
static struct drm_mm_node *
next_hole(struct drm_mm *mm,
struct drm_mm_node *node,
u64 size,
enum drm_mm_insert_mode mode)
{
switch (mode) {
default:
case DRM_MM_INSERT_BEST:
return rb_hole_size_to_node(rb_prev(&node->rb_hole_size));
case DRM_MM_INSERT_LOW:
return next_hole_low_addr(node, size);
case DRM_MM_INSERT_HIGH:
return next_hole_high_addr(node, size);
case DRM_MM_INSERT_EVICT:
node = list_next_entry(node, hole_stack);
return &node->hole_stack == &mm->hole_stack ? NULL : node;
}
}
/**
* drm_mm_reserve_node - insert an pre-initialized node
* @mm: drm_mm allocator to insert @node into
* @node: drm_mm_node to insert
*
* This functions inserts an already set-up &drm_mm_node into the allocator,
* meaning that start, size and color must be set by the caller. All other
* fields must be cleared to 0. This is useful to initialize the allocator with
* preallocated objects which must be set-up before the range allocator can be
* set-up, e.g. when taking over a firmware framebuffer.
*
* Returns:
* 0 on success, -ENOSPC if there's no hole where @node is.
*/
int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
{
struct drm_mm_node *hole;
u64 hole_start, hole_end;
u64 adj_start, adj_end;
u64 end;
end = node->start + node->size;
if (unlikely(end <= node->start))
return -ENOSPC;
/* Find the relevant hole to add our node to */
hole = find_hole_addr(mm, node->start, 0);
if (!hole)
return -ENOSPC;
adj_start = hole_start = __drm_mm_hole_node_start(hole);
adj_end = hole_end = hole_start + hole->hole_size;
if (mm->color_adjust)
mm->color_adjust(hole, node->color, &adj_start, &adj_end);
if (adj_start > node->start || adj_end < end)
return -ENOSPC;
node->mm = mm;
__set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
list_add(&node->node_list, &hole->node_list);
drm_mm_interval_tree_add_node(hole, node);
node->hole_size = 0;
rm_hole(hole);
if (node->start > hole_start)
add_hole(hole);
if (end < hole_end)
add_hole(node);
save_stack(node);
return 0;
}
EXPORT_SYMBOL(drm_mm_reserve_node);
static u64 rb_to_hole_size_or_zero(struct rb_node *rb)
{
return rb ? rb_to_hole_size(rb) : 0;
}
/**
* drm_mm_insert_node_in_range - ranged search for space and insert @node
* @mm: drm_mm to allocate from
* @node: preallocate node to insert
* @size: size of the allocation
* @alignment: alignment of the allocation
* @color: opaque tag value to use for this node
* @range_start: start of the allowed range for this node
* @range_end: end of the allowed range for this node
* @mode: fine-tune the allocation search and placement
*
* The preallocated @node must be cleared to 0.
*
* Returns:
* 0 on success, -ENOSPC if there's no suitable hole.
*/
int drm_mm_insert_node_in_range(struct drm_mm * const mm,
struct drm_mm_node * const node,
u64 size, u64 alignment,
unsigned long color,
u64 range_start, u64 range_end,
enum drm_mm_insert_mode mode)
{
struct drm_mm_node *hole;
u64 remainder_mask;
bool once;
DRM_MM_BUG_ON(range_start > range_end);
if (unlikely(size == 0 || range_end - range_start < size))
return -ENOSPC;
if (rb_to_hole_size_or_zero(rb_first_cached(&mm->holes_size)) < size)
return -ENOSPC;
if (alignment <= 1)
alignment = 0;
once = mode & DRM_MM_INSERT_ONCE;
mode &= ~DRM_MM_INSERT_ONCE;
remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0;
for (hole = first_hole(mm, range_start, range_end, size, mode);
hole;
hole = once ? NULL : next_hole(mm, hole, size, mode)) {
u64 hole_start = __drm_mm_hole_node_start(hole);
u64 hole_end = hole_start + hole->hole_size;
u64 adj_start, adj_end;
u64 col_start, col_end;
if (mode == DRM_MM_INSERT_LOW && hole_start >= range_end)
break;
if (mode == DRM_MM_INSERT_HIGH && hole_end <= range_start)
break;
col_start = hole_start;
col_end = hole_end;
if (mm->color_adjust)
mm->color_adjust(hole, color, &col_start, &col_end);
adj_start = max(col_start, range_start);
adj_end = min(col_end, range_end);
if (adj_end <= adj_start || adj_end - adj_start < size)
continue;
if (mode == DRM_MM_INSERT_HIGH)
adj_start = adj_end - size;
if (alignment) {
u64 rem;
if (likely(remainder_mask))
rem = adj_start & remainder_mask;
else
div64_u64_rem(adj_start, alignment, &rem);
if (rem) {
adj_start -= rem;
if (mode != DRM_MM_INSERT_HIGH)
adj_start += alignment;
if (adj_start < max(col_start, range_start) ||
min(col_end, range_end) - adj_start < size)
continue;
if (adj_end <= adj_start ||
adj_end - adj_start < size)
continue;
}
}
node->mm = mm;
node->size = size;
node->start = adj_start;
node->color = color;
node->hole_size = 0;
__set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
list_add(&node->node_list, &hole->node_list);
drm_mm_interval_tree_add_node(hole, node);
rm_hole(hole);
if (adj_start > hole_start)
add_hole(hole);
if (adj_start + size < hole_end)
add_hole(node);
save_stack(node);
return 0;
}
return -ENOSPC;
}
EXPORT_SYMBOL(drm_mm_insert_node_in_range);
static inline bool drm_mm_node_scanned_block(const struct drm_mm_node *node)
{
return test_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags);
}
/**
* drm_mm_remove_node - Remove a memory node from the allocator.
* @node: drm_mm_node to remove
*
* This just removes a node from its drm_mm allocator. The node does not need to
* be cleared again before it can be re-inserted into this or any other drm_mm
* allocator. It is a bug to call this function on a unallocated node.
*/
void drm_mm_remove_node(struct drm_mm_node *node)
{
struct drm_mm *mm = node->mm;
struct drm_mm_node *prev_node;
DRM_MM_BUG_ON(!drm_mm_node_allocated(node));
DRM_MM_BUG_ON(drm_mm_node_scanned_block(node));
prev_node = list_prev_entry(node, node_list);
if (drm_mm_hole_follows(node))
rm_hole(node);
drm_mm_interval_tree_remove(node, &mm->interval_tree);
list_del(&node->node_list);
if (drm_mm_hole_follows(prev_node))
rm_hole(prev_node);
add_hole(prev_node);
clear_bit_unlock(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
}
EXPORT_SYMBOL(drm_mm_remove_node);
/**
* DOC: lru scan roster
*
* Very often GPUs need to have continuous allocations for a given object. When
* evicting objects to make space for a new one it is therefore not most
* efficient when we simply start to select all objects from the tail of an LRU
* until there's a suitable hole: Especially for big objects or nodes that
* otherwise have special allocation constraints there's a good chance we evict
* lots of (smaller) objects unnecessarily.
*
* The DRM range allocator supports this use-case through the scanning
* interfaces. First a scan operation needs to be initialized with
* drm_mm_scan_init() or drm_mm_scan_init_with_range(). The driver adds
* objects to the roster, probably by walking an LRU list, but this can be
* freely implemented. Eviction candidates are added using
* drm_mm_scan_add_block() until a suitable hole is found or there are no
* further evictable objects. Eviction roster metadata is tracked in &struct
* drm_mm_scan.
*
* The driver must walk through all objects again in exactly the reverse
* order to restore the allocator state. Note that while the allocator is used
* in the scan mode no other operation is allowed.
*
* Finally the driver evicts all objects selected (drm_mm_scan_remove_block()
* reported true) in the scan, and any overlapping nodes after color adjustment
* (drm_mm_scan_color_evict()). Adding and removing an object is O(1), and
* since freeing a node is also O(1) the overall complexity is
* O(scanned_objects). So like the free stack which needs to be walked before a
* scan operation even begins this is linear in the number of objects. It
* doesn't seem to hurt too badly.
*/
/**
* drm_mm_scan_init_with_range - initialize range-restricted lru scanning
* @scan: scan state
* @mm: drm_mm to scan
* @size: size of the allocation
* @alignment: alignment of the allocation
* @color: opaque tag value to use for the allocation
* @start: start of the allowed range for the allocation
* @end: end of the allowed range for the allocation
* @mode: fine-tune the allocation search and placement
*
* 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_scan_init_with_range(struct drm_mm_scan *scan,
struct drm_mm *mm,
u64 size,
u64 alignment,
unsigned long color,
u64 start,
u64 end,
enum drm_mm_insert_mode mode)
{
DRM_MM_BUG_ON(start >= end);
DRM_MM_BUG_ON(!size || size > end - start);
DRM_MM_BUG_ON(mm->scan_active);
scan->mm = mm;
if (alignment <= 1)
alignment = 0;
scan->color = color;
scan->alignment = alignment;
scan->remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0;
scan->size = size;
scan->mode = mode;
DRM_MM_BUG_ON(end <= start);
scan->range_start = start;
scan->range_end = end;
scan->hit_start = U64_MAX;
scan->hit_end = 0;
}
EXPORT_SYMBOL(drm_mm_scan_init_with_range);
/**
* drm_mm_scan_add_block - add a node to the scan list
* @scan: the active drm_mm scanner
* @node: drm_mm_node to add
*
* Add a node to the scan list that might be freed to make space for the desired
* hole.
*
* Returns:
* True if a hole has been found, false otherwise.
*/
bool drm_mm_scan_add_block(struct drm_mm_scan *scan,
struct drm_mm_node *node)
{
struct drm_mm *mm = scan->mm;
struct drm_mm_node *hole;
u64 hole_start, hole_end;
u64 col_start, col_end;
u64 adj_start, adj_end;
DRM_MM_BUG_ON(node->mm != mm);
DRM_MM_BUG_ON(!drm_mm_node_allocated(node));
DRM_MM_BUG_ON(drm_mm_node_scanned_block(node));
__set_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags);
mm->scan_active++;
/* Remove this block from the node_list so that we enlarge the hole
* (distance between the end of our previous node and the start of
* or next), without poisoning the link so that we can restore it
* later in drm_mm_scan_remove_block().
*/
hole = list_prev_entry(node, node_list);
DRM_MM_BUG_ON(list_next_entry(hole, node_list) != node);
__list_del_entry(&node->node_list);
hole_start = __drm_mm_hole_node_start(hole);
hole_end = __drm_mm_hole_node_end(hole);
col_start = hole_start;
col_end = hole_end;
if (mm->color_adjust)
mm->color_adjust(hole, scan->color, &col_start, &col_end);
adj_start = max(col_start, scan->range_start);
adj_end = min(col_end, scan->range_end);
if (adj_end <= adj_start || adj_end - adj_start < scan->size)
return false;
if (scan->mode == DRM_MM_INSERT_HIGH)
adj_start = adj_end - scan->size;
if (scan->alignment) {
u64 rem;
if (likely(scan->remainder_mask))
rem = adj_start & scan->remainder_mask;
else
div64_u64_rem(adj_start, scan->alignment, &rem);
if (rem) {
adj_start -= rem;
if (scan->mode != DRM_MM_INSERT_HIGH)
adj_start += scan->alignment;
if (adj_start < max(col_start, scan->range_start) ||
min(col_end, scan->range_end) - adj_start < scan->size)
return false;
if (adj_end <= adj_start ||
adj_end - adj_start < scan->size)
return false;
}
}
scan->hit_start = adj_start;
scan->hit_end = adj_start + scan->size;
DRM_MM_BUG_ON(scan->hit_start >= scan->hit_end);
DRM_MM_BUG_ON(scan->hit_start < hole_start);
DRM_MM_BUG_ON(scan->hit_end > hole_end);
return true;
}
EXPORT_SYMBOL(drm_mm_scan_add_block);
/**
* drm_mm_scan_remove_block - remove a node from the scan list
* @scan: the active drm_mm scanner
* @node: drm_mm_node to remove
*
* Nodes **must** be removed in exactly the reverse order from the scan list as
* they have been added (e.g. using list_add() as they are added and then
* list_for_each() over that eviction list to remove), 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
* immediately following drm_mm_insert_node_in_range_generic() or one of the
* simpler versions of that function with !DRM_MM_SEARCH_BEST will then return
* the just freed block (because it's at the top of the free_stack list).
*
* Returns:
* True if this block should be evicted, false otherwise. Will always
* return false when no hole has been found.
*/
bool drm_mm_scan_remove_block(struct drm_mm_scan *scan,
struct drm_mm_node *node)
{
struct drm_mm_node *prev_node;
DRM_MM_BUG_ON(node->mm != scan->mm);
DRM_MM_BUG_ON(!drm_mm_node_scanned_block(node));
__clear_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags);
DRM_MM_BUG_ON(!node->mm->scan_active);
node->mm->scan_active--;
/* During drm_mm_scan_add_block() we decoupled this node leaving
* its pointers intact. Now that the caller is walking back along
* the eviction list we can restore this block into its rightful
* place on the full node_list. To confirm that the caller is walking
* backwards correctly we check that prev_node->next == node->next,
* i.e. both believe the same node should be on the other side of the
* hole.
*/
prev_node = list_prev_entry(node, node_list);
DRM_MM_BUG_ON(list_next_entry(prev_node, node_list) !=
list_next_entry(node, node_list));
list_add(&node->node_list, &prev_node->node_list);
return (node->start + node->size > scan->hit_start &&
node->start < scan->hit_end);
}
EXPORT_SYMBOL(drm_mm_scan_remove_block);
/**
* drm_mm_scan_color_evict - evict overlapping nodes on either side of hole
* @scan: drm_mm scan with target hole
*
* After completing an eviction scan and removing the selected nodes, we may
* need to remove a few more nodes from either side of the target hole if
* mm.color_adjust is being used.
*
* Returns:
* A node to evict, or NULL if there are no overlapping nodes.
*/
struct drm_mm_node *drm_mm_scan_color_evict(struct drm_mm_scan *scan)
{
struct drm_mm *mm = scan->mm;
struct drm_mm_node *hole;
u64 hole_start, hole_end;
DRM_MM_BUG_ON(list_empty(&mm->hole_stack));
if (!mm->color_adjust)
return NULL;
/*
* The hole found during scanning should ideally be the first element
* in the hole_stack list, but due to side-effects in the driver it
* may not be.
*/
list_for_each_entry(hole, &mm->hole_stack, hole_stack) {
hole_start = __drm_mm_hole_node_start(hole);
hole_end = hole_start + hole->hole_size;
if (hole_start <= scan->hit_start &&
hole_end >= scan->hit_end)
break;
}
/* We should only be called after we found the hole previously */
DRM_MM_BUG_ON(&hole->hole_stack == &mm->hole_stack);
if (unlikely(&hole->hole_stack == &mm->hole_stack))
return NULL;
DRM_MM_BUG_ON(hole_start > scan->hit_start);
DRM_MM_BUG_ON(hole_end < scan->hit_end);
mm->color_adjust(hole, scan->color, &hole_start, &hole_end);
if (hole_start > scan->hit_start)
return hole;
if (hole_end < scan->hit_end)
return list_next_entry(hole, node_list);
return NULL;
}
EXPORT_SYMBOL(drm_mm_scan_color_evict);
/**
* drm_mm_init - initialize a drm-mm allocator
* @mm: the drm_mm structure to initialize
* @start: start of the range managed by @mm
* @size: end of the range managed by @mm
*
* Note that @mm must be cleared to 0 before calling this function.
*/
void drm_mm_init(struct drm_mm *mm, u64 start, u64 size)
{
DRM_MM_BUG_ON(start + size <= start);
mm->color_adjust = NULL;
INIT_LIST_HEAD(&mm->hole_stack);
mm->interval_tree = RB_ROOT_CACHED;
mm->holes_size = RB_ROOT_CACHED;
mm->holes_addr = RB_ROOT;
/* Clever trick to avoid a special case in the free hole tracking. */
INIT_LIST_HEAD(&mm->head_node.node_list);
mm->head_node.flags = 0;
mm->head_node.mm = mm;
mm->head_node.start = start + size;
mm->head_node.size = -size;
add_hole(&mm->head_node);
mm->scan_active = 0;
#ifdef CONFIG_DRM_DEBUG_MM
stack_depot_init();
#endif
}
EXPORT_SYMBOL(drm_mm_init);
/**
* drm_mm_takedown - clean up a drm_mm allocator
* @mm: drm_mm allocator to clean up
*
* Note that it is a bug to call this function on an allocator which is not
* clean.
*/
void drm_mm_takedown(struct drm_mm *mm)
{
if (WARN(!drm_mm_clean(mm),
"Memory manager not clean during takedown.\n"))
show_leaks(mm);
}
EXPORT_SYMBOL(drm_mm_takedown);
static u64 drm_mm_dump_hole(struct drm_printer *p, const struct drm_mm_node *entry)
{
u64 start, size;
size = entry->hole_size;
if (size) {
start = drm_mm_hole_node_start(entry);
drm_printf(p, "%#018llx-%#018llx: %llu: free\n",
start, start + size, size);
}
return size;
}
/**
* drm_mm_print - print allocator state
* @mm: drm_mm allocator to print
* @p: DRM printer to use
*/
void drm_mm_print(const struct drm_mm *mm, struct drm_printer *p)
{
const struct drm_mm_node *entry;
u64 total_used = 0, total_free = 0, total = 0;
total_free += drm_mm_dump_hole(p, &mm->head_node);
drm_mm_for_each_node(entry, mm) {
drm_printf(p, "%#018llx-%#018llx: %llu: used\n", entry->start,
entry->start + entry->size, entry->size);
total_used += entry->size;
total_free += drm_mm_dump_hole(p, entry);
}
total = total_free + total_used;
drm_printf(p, "total: %llu, used %llu free %llu\n", total,
total_used, total_free);
}
EXPORT_SYMBOL(drm_mm_print);
Codebase Browser
linux