linux/drivers/gpu/drm/i915/i915_buddy.c
Matthew Auld f4b1b92f41 drm/i915/buddy: avoid double list_add
Be careful not to mark an already free node as free again.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200305204711.217783-1-matthew.auld@intel.com
2020-03-06 14:33:08 +00:00

433 lines
8.8 KiB
C

// SPDX-License-Identifier: MIT
/*
* Copyright © 2019 Intel Corporation
*/
#include <linux/kmemleak.h>
#include <linux/slab.h>
#include "i915_buddy.h"
#include "i915_gem.h"
#include "i915_globals.h"
#include "i915_utils.h"
static struct i915_global_block {
struct i915_global base;
struct kmem_cache *slab_blocks;
} global;
static void i915_global_buddy_shrink(void)
{
kmem_cache_shrink(global.slab_blocks);
}
static void i915_global_buddy_exit(void)
{
kmem_cache_destroy(global.slab_blocks);
}
static struct i915_global_block global = { {
.shrink = i915_global_buddy_shrink,
.exit = i915_global_buddy_exit,
} };
int __init i915_global_buddy_init(void)
{
global.slab_blocks = KMEM_CACHE(i915_buddy_block, SLAB_HWCACHE_ALIGN);
if (!global.slab_blocks)
return -ENOMEM;
i915_global_register(&global.base);
return 0;
}
static struct i915_buddy_block *i915_block_alloc(struct i915_buddy_block *parent,
unsigned int order,
u64 offset)
{
struct i915_buddy_block *block;
block = kmem_cache_zalloc(global.slab_blocks, GFP_KERNEL);
if (!block)
return NULL;
block->header = offset;
block->header |= order;
block->parent = parent;
return block;
}
static void i915_block_free(struct i915_buddy_block *block)
{
kmem_cache_free(global.slab_blocks, block);
}
static void mark_allocated(struct i915_buddy_block *block)
{
block->header &= ~I915_BUDDY_HEADER_STATE;
block->header |= I915_BUDDY_ALLOCATED;
list_del(&block->link);
}
static void mark_free(struct i915_buddy_mm *mm,
struct i915_buddy_block *block)
{
block->header &= ~I915_BUDDY_HEADER_STATE;
block->header |= I915_BUDDY_FREE;
list_add(&block->link,
&mm->free_list[i915_buddy_block_order(block)]);
}
static void mark_split(struct i915_buddy_block *block)
{
block->header &= ~I915_BUDDY_HEADER_STATE;
block->header |= I915_BUDDY_SPLIT;
list_del(&block->link);
}
int i915_buddy_init(struct i915_buddy_mm *mm, u64 size, u64 chunk_size)
{
unsigned int i;
u64 offset;
if (size < chunk_size)
return -EINVAL;
if (chunk_size < PAGE_SIZE)
return -EINVAL;
if (!is_power_of_2(chunk_size))
return -EINVAL;
size = round_down(size, chunk_size);
mm->size = size;
mm->chunk_size = chunk_size;
mm->max_order = ilog2(size) - ilog2(chunk_size);
GEM_BUG_ON(mm->max_order > I915_BUDDY_MAX_ORDER);
mm->free_list = kmalloc_array(mm->max_order + 1,
sizeof(struct list_head),
GFP_KERNEL);
if (!mm->free_list)
return -ENOMEM;
for (i = 0; i <= mm->max_order; ++i)
INIT_LIST_HEAD(&mm->free_list[i]);
mm->n_roots = hweight64(size);
mm->roots = kmalloc_array(mm->n_roots,
sizeof(struct i915_buddy_block *),
GFP_KERNEL);
if (!mm->roots)
goto out_free_list;
offset = 0;
i = 0;
/*
* Split into power-of-two blocks, in case we are given a size that is
* not itself a power-of-two.
*/
do {
struct i915_buddy_block *root;
unsigned int order;
u64 root_size;
root_size = rounddown_pow_of_two(size);
order = ilog2(root_size) - ilog2(chunk_size);
root = i915_block_alloc(NULL, order, offset);
if (!root)
goto out_free_roots;
mark_free(mm, root);
GEM_BUG_ON(i > mm->max_order);
GEM_BUG_ON(i915_buddy_block_size(mm, root) < chunk_size);
mm->roots[i] = root;
offset += root_size;
size -= root_size;
i++;
} while (size);
return 0;
out_free_roots:
while (i--)
i915_block_free(mm->roots[i]);
kfree(mm->roots);
out_free_list:
kfree(mm->free_list);
return -ENOMEM;
}
void i915_buddy_fini(struct i915_buddy_mm *mm)
{
int i;
for (i = 0; i < mm->n_roots; ++i) {
GEM_WARN_ON(!i915_buddy_block_is_free(mm->roots[i]));
i915_block_free(mm->roots[i]);
}
kfree(mm->roots);
kfree(mm->free_list);
}
static int split_block(struct i915_buddy_mm *mm,
struct i915_buddy_block *block)
{
unsigned int block_order = i915_buddy_block_order(block) - 1;
u64 offset = i915_buddy_block_offset(block);
GEM_BUG_ON(!i915_buddy_block_is_free(block));
GEM_BUG_ON(!i915_buddy_block_order(block));
block->left = i915_block_alloc(block, block_order, offset);
if (!block->left)
return -ENOMEM;
block->right = i915_block_alloc(block, block_order,
offset + (mm->chunk_size << block_order));
if (!block->right) {
i915_block_free(block->left);
return -ENOMEM;
}
mark_free(mm, block->left);
mark_free(mm, block->right);
mark_split(block);
return 0;
}
static struct i915_buddy_block *
get_buddy(struct i915_buddy_block *block)
{
struct i915_buddy_block *parent;
parent = block->parent;
if (!parent)
return NULL;
if (parent->left == block)
return parent->right;
return parent->left;
}
static void __i915_buddy_free(struct i915_buddy_mm *mm,
struct i915_buddy_block *block)
{
struct i915_buddy_block *parent;
while ((parent = block->parent)) {
struct i915_buddy_block *buddy;
buddy = get_buddy(block);
if (!i915_buddy_block_is_free(buddy))
break;
list_del(&buddy->link);
i915_block_free(block);
i915_block_free(buddy);
block = parent;
}
mark_free(mm, block);
}
void i915_buddy_free(struct i915_buddy_mm *mm,
struct i915_buddy_block *block)
{
GEM_BUG_ON(!i915_buddy_block_is_allocated(block));
__i915_buddy_free(mm, block);
}
void i915_buddy_free_list(struct i915_buddy_mm *mm, struct list_head *objects)
{
struct i915_buddy_block *block, *on;
list_for_each_entry_safe(block, on, objects, link) {
i915_buddy_free(mm, block);
cond_resched();
}
INIT_LIST_HEAD(objects);
}
/*
* Allocate power-of-two block. The order value here translates to:
*
* 0 = 2^0 * mm->chunk_size
* 1 = 2^1 * mm->chunk_size
* 2 = 2^2 * mm->chunk_size
* ...
*/
struct i915_buddy_block *
i915_buddy_alloc(struct i915_buddy_mm *mm, unsigned int order)
{
struct i915_buddy_block *block = NULL;
unsigned int i;
int err;
for (i = order; i <= mm->max_order; ++i) {
block = list_first_entry_or_null(&mm->free_list[i],
struct i915_buddy_block,
link);
if (block)
break;
}
if (!block)
return ERR_PTR(-ENOSPC);
GEM_BUG_ON(!i915_buddy_block_is_free(block));
while (i != order) {
err = split_block(mm, block);
if (unlikely(err))
goto out_free;
/* Go low */
block = block->left;
i--;
}
mark_allocated(block);
kmemleak_update_trace(block);
return block;
out_free:
if (i != order)
__i915_buddy_free(mm, block);
return ERR_PTR(err);
}
static inline bool overlaps(u64 s1, u64 e1, u64 s2, u64 e2)
{
return s1 <= e2 && e1 >= s2;
}
static inline bool contains(u64 s1, u64 e1, u64 s2, u64 e2)
{
return s1 <= s2 && e1 >= e2;
}
/*
* Allocate range. Note that it's safe to chain together multiple alloc_ranges
* with the same blocks list.
*
* Intended for pre-allocating portions of the address space, for example to
* reserve a block for the initial framebuffer or similar, hence the expectation
* here is that i915_buddy_alloc() is still the main vehicle for
* allocations, so if that's not the case then the drm_mm range allocator is
* probably a much better fit, and so you should probably go use that instead.
*/
int i915_buddy_alloc_range(struct i915_buddy_mm *mm,
struct list_head *blocks,
u64 start, u64 size)
{
struct i915_buddy_block *block;
struct i915_buddy_block *buddy;
LIST_HEAD(allocated);
LIST_HEAD(dfs);
u64 end;
int err;
int i;
if (size < mm->chunk_size)
return -EINVAL;
if (!IS_ALIGNED(size | start, mm->chunk_size))
return -EINVAL;
if (range_overflows(start, size, mm->size))
return -EINVAL;
for (i = 0; i < mm->n_roots; ++i)
list_add_tail(&mm->roots[i]->tmp_link, &dfs);
end = start + size - 1;
do {
u64 block_start;
u64 block_end;
block = list_first_entry_or_null(&dfs,
struct i915_buddy_block,
tmp_link);
if (!block)
break;
list_del(&block->tmp_link);
block_start = i915_buddy_block_offset(block);
block_end = block_start + i915_buddy_block_size(mm, block) - 1;
if (!overlaps(start, end, block_start, block_end))
continue;
if (i915_buddy_block_is_allocated(block)) {
err = -ENOSPC;
goto err_free;
}
if (contains(start, end, block_start, block_end)) {
if (!i915_buddy_block_is_free(block)) {
err = -ENOSPC;
goto err_free;
}
mark_allocated(block);
list_add_tail(&block->link, &allocated);
continue;
}
if (!i915_buddy_block_is_split(block)) {
err = split_block(mm, block);
if (unlikely(err))
goto err_undo;
}
list_add(&block->right->tmp_link, &dfs);
list_add(&block->left->tmp_link, &dfs);
} while (1);
list_splice_tail(&allocated, blocks);
return 0;
err_undo:
/*
* We really don't want to leave around a bunch of split blocks, since
* bigger is better, so make sure we merge everything back before we
* free the allocated blocks.
*/
buddy = get_buddy(block);
if (buddy &&
(i915_buddy_block_is_free(block) &&
i915_buddy_block_is_free(buddy)))
__i915_buddy_free(mm, block);
err_free:
i915_buddy_free_list(mm, &allocated);
return err;
}
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftests/i915_buddy.c"
#endif