[Intel-gfx] [PATCH v12 1/5] drm: improve drm_buddy_alloc function
Christian König
ckoenig.leichtzumerken at gmail.com
Mon Feb 14 09:12:48 UTC 2022
Am 14.02.22 um 09:36 schrieb Matthew Auld:
> On Mon, 14 Feb 2022 at 06:32, Christian König
> <ckoenig.leichtzumerken at gmail.com> wrote:
>> Am 13.02.22 um 09:52 schrieb Arunpravin:
>>> - Make drm_buddy_alloc a single function to handle
>>> range allocation and non-range allocation demands
>>>
>>> - Implemented a new function alloc_range() which allocates
>>> the requested power-of-two block comply with range limitations
>>>
>>> - Moved order computation and memory alignment logic from
>>> i915 driver to drm buddy
>>>
>>> v2:
>>> merged below changes to keep the build unbroken
>>> - drm_buddy_alloc_range() becomes obsolete and may be removed
>>> - enable ttm range allocation (fpfn / lpfn) support in i915 driver
>>> - apply enhanced drm_buddy_alloc() function to i915 driver
>>>
>>> v3(Matthew Auld):
>>> - Fix alignment issues and remove unnecessary list_empty check
>>> - add more validation checks for input arguments
>>> - make alloc_range() block allocations as bottom-up
>>> - optimize order computation logic
>>> - replace uint64_t with u64, which is preferred in the kernel
>>>
>>> v4(Matthew Auld):
>>> - keep drm_buddy_alloc_range() function implementation for generic
>>> actual range allocations
>>> - keep alloc_range() implementation for end bias allocations
>>>
>>> v5(Matthew Auld):
>>> - modify drm_buddy_alloc() passing argument place->lpfn to lpfn
>>> as place->lpfn will currently always be zero for i915
>>>
>>> v6(Matthew Auld):
>>> - fixup potential uaf - If we are unlucky and can't allocate
>>> enough memory when splitting blocks, where we temporarily
>>> end up with the given block and its buddy on the respective
>>> free list, then we need to ensure we delete both blocks,
>>> and no just the buddy, before potentially freeing them
>>>
>>> - fix warnings reported by kernel test robot <lkp at intel.com>
>>>
>>> v7(Matthew Auld):
>>> - revert fixup potential uaf
>>> - keep __alloc_range() add node to the list logic same as
>>> drm_buddy_alloc_blocks() by having a temporary list variable
>>> - at drm_buddy_alloc_blocks() keep i915 range_overflows macro
>>> and add a new check for end variable
>>>
>>> v8:
>>> - fix warnings reported by kernel test robot <lkp at intel.com>
>>>
>>> v9(Matthew Auld):
>>> - remove DRM_BUDDY_RANGE_ALLOCATION flag
>>> - remove unnecessary function description
>>>
>>> Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam at amd.com>
>>> Reviewed-by: Matthew Auld <matthew.auld at intel.com>
>> As long as nobody objects I'm going to push patches 1-3 to drm-misc-next
>> in the next hour or so:
> As part of this could you also push
> https://patchwork.freedesktop.org/series/99842/ ?
Sure, but Arun said in our internal chat that I should wait with that
anyway since he wanted to sort out one more issue.
Christian.
>
>> Then going to take a deeper look into patches 4 and 5 to get them reviewed.
>>
>> Thanks,
>> Christian.
>>
>>> ---
>>> drivers/gpu/drm/drm_buddy.c | 292 +++++++++++++-----
>>> drivers/gpu/drm/i915/i915_ttm_buddy_manager.c | 63 ++--
>>> drivers/gpu/drm/i915/i915_ttm_buddy_manager.h | 2 +
>>> include/drm/drm_buddy.h | 11 +-
>>> 4 files changed, 250 insertions(+), 118 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
>>> index d60878bc9c20..e0c0d786a572 100644
>>> --- a/drivers/gpu/drm/drm_buddy.c
>>> +++ b/drivers/gpu/drm/drm_buddy.c
>>> @@ -282,23 +282,97 @@ void drm_buddy_free_list(struct drm_buddy *mm, struct list_head *objects)
>>> }
>>> EXPORT_SYMBOL(drm_buddy_free_list);
>>>
>>> -/**
>>> - * drm_buddy_alloc_blocks - allocate power-of-two blocks
>>> - *
>>> - * @mm: DRM buddy manager to allocate from
>>> - * @order: size of the allocation
>>> - *
>>> - * The order value here translates to:
>>> - *
>>> - * 0 = 2^0 * mm->chunk_size
>>> - * 1 = 2^1 * mm->chunk_size
>>> - * 2 = 2^2 * mm->chunk_size
>>> - *
>>> - * Returns:
>>> - * allocated ptr to the &drm_buddy_block on success
>>> - */
>>> -struct drm_buddy_block *
>>> -drm_buddy_alloc_blocks(struct drm_buddy *mm, unsigned int order)
>>> +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;
>>> +}
>>> +
>>> +static struct drm_buddy_block *
>>> +alloc_range_bias(struct drm_buddy *mm,
>>> + u64 start, u64 end,
>>> + unsigned int order)
>>> +{
>>> + struct drm_buddy_block *block;
>>> + struct drm_buddy_block *buddy;
>>> + LIST_HEAD(dfs);
>>> + int err;
>>> + int i;
>>> +
>>> + end = end - 1;
>>> +
>>> + for (i = 0; i < mm->n_roots; ++i)
>>> + list_add_tail(&mm->roots[i]->tmp_link, &dfs);
>>> +
>>> + do {
>>> + u64 block_start;
>>> + u64 block_end;
>>> +
>>> + block = list_first_entry_or_null(&dfs,
>>> + struct drm_buddy_block,
>>> + tmp_link);
>>> + if (!block)
>>> + break;
>>> +
>>> + list_del(&block->tmp_link);
>>> +
>>> + if (drm_buddy_block_order(block) < order)
>>> + continue;
>>> +
>>> + block_start = drm_buddy_block_offset(block);
>>> + block_end = block_start + drm_buddy_block_size(mm, block) - 1;
>>> +
>>> + if (!overlaps(start, end, block_start, block_end))
>>> + continue;
>>> +
>>> + if (drm_buddy_block_is_allocated(block))
>>> + continue;
>>> +
>>> + if (contains(start, end, block_start, block_end) &&
>>> + order == drm_buddy_block_order(block)) {
>>> + /*
>>> + * Find the free block within the range.
>>> + */
>>> + if (drm_buddy_block_is_free(block))
>>> + return block;
>>> +
>>> + continue;
>>> + }
>>> +
>>> + if (!drm_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);
>>> +
>>> + return ERR_PTR(-ENOSPC);
>>> +
>>> +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 &&
>>> + (drm_buddy_block_is_free(block) &&
>>> + drm_buddy_block_is_free(buddy)))
>>> + __drm_buddy_free(mm, block);
>>> + return ERR_PTR(err);
>>> +}
>>> +
>>> +static struct drm_buddy_block *
>>> +alloc_from_freelist(struct drm_buddy *mm,
>>> + unsigned int order,
>>> + unsigned long flags)
>>> {
>>> struct drm_buddy_block *block = NULL;
>>> unsigned int i;
>>> @@ -320,78 +394,29 @@ drm_buddy_alloc_blocks(struct drm_buddy *mm, unsigned int order)
>>> while (i != order) {
>>> err = split_block(mm, block);
>>> if (unlikely(err))
>>> - goto out_free;
>>> + goto err_undo;
>>>
>>> - /* Go low */
>>> - block = block->left;
>>> + block = block->right;
>>> i--;
>>> }
>>> -
>>> - mark_allocated(block);
>>> - mm->avail -= drm_buddy_block_size(mm, block);
>>> - kmemleak_update_trace(block);
>>> return block;
>>>
>>> -out_free:
>>> +err_undo:
>>> if (i != order)
>>> __drm_buddy_free(mm, block);
>>> return ERR_PTR(err);
>>> }
>>> -EXPORT_SYMBOL(drm_buddy_alloc_blocks);
>>> -
>>> -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;
>>> -}
>>>
>>> -/**
>>> - * drm_buddy_alloc_range - allocate range
>>> - *
>>> - * @mm: DRM buddy manager to allocate from
>>> - * @blocks: output list head to add allocated blocks
>>> - * @start: start of the allowed range for this block
>>> - * @size: size of the allocation
>>> - *
>>> - * 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 drm_buddy_alloc_blocks() 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.
>>> - *
>>> - * Note that it's safe to chain together multiple alloc_ranges
>>> - * with the same blocks list
>>> - *
>>> - * Returns:
>>> - * 0 on success, error code on failure.
>>> - */
>>> -int drm_buddy_alloc_range(struct drm_buddy *mm,
>>> - struct list_head *blocks,
>>> - u64 start, u64 size)
>>> +static int __alloc_range(struct drm_buddy *mm,
>>> + struct list_head *dfs,
>>> + u64 start, u64 size,
>>> + struct list_head *blocks)
>>> {
>>> struct drm_buddy_block *block;
>>> struct drm_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;
>>>
>>> @@ -399,7 +424,7 @@ int drm_buddy_alloc_range(struct drm_buddy *mm,
>>> u64 block_start;
>>> u64 block_end;
>>>
>>> - block = list_first_entry_or_null(&dfs,
>>> + block = list_first_entry_or_null(dfs,
>>> struct drm_buddy_block,
>>> tmp_link);
>>> if (!block)
>>> @@ -436,8 +461,8 @@ int drm_buddy_alloc_range(struct drm_buddy *mm,
>>> goto err_undo;
>>> }
>>>
>>> - list_add(&block->right->tmp_link, &dfs);
>>> - list_add(&block->left->tmp_link, &dfs);
>>> + list_add(&block->right->tmp_link, dfs);
>>> + list_add(&block->left->tmp_link, dfs);
>>> } while (1);
>>>
>>> list_splice_tail(&allocated, blocks);
>>> @@ -459,7 +484,120 @@ int drm_buddy_alloc_range(struct drm_buddy *mm,
>>> drm_buddy_free_list(mm, &allocated);
>>> return err;
>>> }
>>> -EXPORT_SYMBOL(drm_buddy_alloc_range);
>>> +
>>> +static int __drm_buddy_alloc_range(struct drm_buddy *mm,
>>> + u64 start,
>>> + u64 size,
>>> + struct list_head *blocks)
>>> +{
>>> + LIST_HEAD(dfs);
>>> + int i;
>>> +
>>> + for (i = 0; i < mm->n_roots; ++i)
>>> + list_add_tail(&mm->roots[i]->tmp_link, &dfs);
>>> +
>>> + return __alloc_range(mm, &dfs, start, size, blocks);
>>> +}
>>> +
>>> +/**
>>> + * drm_buddy_alloc_blocks - allocate power-of-two blocks
>>> + *
>>> + * @mm: DRM buddy manager to allocate from
>>> + * @start: start of the allowed range for this block
>>> + * @end: end of the allowed range for this block
>>> + * @size: size of the allocation
>>> + * @min_page_size: alignment of the allocation
>>> + * @blocks: output list head to add allocated blocks
>>> + * @flags: DRM_BUDDY_*_ALLOCATION flags
>>> + *
>>> + * alloc_range_bias() called on range limitations, which traverses
>>> + * the tree and returns the desired block.
>>> + *
>>> + * alloc_from_freelist() called when *no* range restrictions
>>> + * are enforced, which picks the block from the freelist.
>>> + *
>>> + * Returns:
>>> + * 0 on success, error code on failure.
>>> + */
>>> +int drm_buddy_alloc_blocks(struct drm_buddy *mm,
>>> + u64 start, u64 end, u64 size,
>>> + u64 min_page_size,
>>> + struct list_head *blocks,
>>> + unsigned long flags)
>>> +{
>>> + struct drm_buddy_block *block = NULL;
>>> + unsigned int min_order, order;
>>> + unsigned long pages;
>>> + LIST_HEAD(allocated);
>>> + int err;
>>> +
>>> + if (size < mm->chunk_size)
>>> + return -EINVAL;
>>> +
>>> + if (min_page_size < mm->chunk_size)
>>> + return -EINVAL;
>>> +
>>> + if (!is_power_of_2(min_page_size))
>>> + return -EINVAL;
>>> +
>>> + if (!IS_ALIGNED(start | end | size, mm->chunk_size))
>>> + return -EINVAL;
>>> +
>>> + if (end > mm->size)
>>> + return -EINVAL;
>>> +
>>> + if (range_overflows(start, size, mm->size))
>>> + return -EINVAL;
>>> +
>>> + /* Actual range allocation */
>>> + if (start + size == end)
>>> + return __drm_buddy_alloc_range(mm, start, size, blocks);
>>> +
>>> + pages = size >> ilog2(mm->chunk_size);
>>> + order = fls(pages) - 1;
>>> + min_order = ilog2(min_page_size) - ilog2(mm->chunk_size);
>>> +
>>> + do {
>>> + order = min(order, (unsigned int)fls(pages) - 1);
>>> + BUG_ON(order > mm->max_order);
>>> + BUG_ON(order < min_order);
>>> +
>>> + do {
>>> + if (start || end != size)
>>> + /* Allocate traversing within the range */
>>> + block = alloc_range_bias(mm, start, end, order);
>>> + else
>>> + /* Allocate from freelist */
>>> + block = alloc_from_freelist(mm, order, flags);
>>> +
>>> + if (!IS_ERR(block))
>>> + break;
>>> +
>>> + if (order-- == min_order) {
>>> + err = -ENOSPC;
>>> + goto err_free;
>>> + }
>>> + } while (1);
>>> +
>>> + mark_allocated(block);
>>> + mm->avail -= drm_buddy_block_size(mm, block);
>>> + kmemleak_update_trace(block);
>>> + list_add_tail(&block->link, &allocated);
>>> +
>>> + pages -= BIT(order);
>>> +
>>> + if (!pages)
>>> + break;
>>> + } while (1);
>>> +
>>> + list_splice_tail(&allocated, blocks);
>>> + return 0;
>>> +
>>> +err_free:
>>> + drm_buddy_free_list(mm, &allocated);
>>> + return err;
>>> +}
>>> +EXPORT_SYMBOL(drm_buddy_alloc_blocks);
>>>
>>> /**
>>> * drm_buddy_block_print - print block information
>>> diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
>>> index 247714bab044..7aef6ad9fe84 100644
>>> --- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
>>> +++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
>>> @@ -36,13 +36,14 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
>>> struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);
>>> struct i915_ttm_buddy_resource *bman_res;
>>> struct drm_buddy *mm = &bman->mm;
>>> - unsigned long n_pages;
>>> - unsigned int min_order;
>>> + unsigned long n_pages, lpfn;
>>> u64 min_page_size;
>>> u64 size;
>>> int err;
>>>
>>> - GEM_BUG_ON(place->fpfn || place->lpfn);
>>> + lpfn = place->lpfn;
>>> + if (!lpfn)
>>> + lpfn = man->size;
>>>
>>> bman_res = kzalloc(sizeof(*bman_res), GFP_KERNEL);
>>> if (!bman_res)
>>> @@ -60,10 +61,16 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
>>> min_page_size = bo->page_alignment << PAGE_SHIFT;
>>>
>>> GEM_BUG_ON(min_page_size < mm->chunk_size);
>>> - min_order = ilog2(min_page_size) - ilog2(mm->chunk_size);
>>> +
>>> if (place->flags & TTM_PL_FLAG_CONTIGUOUS) {
>>> + unsigned long pages;
>>> +
>>> size = roundup_pow_of_two(size);
>>> - min_order = ilog2(size) - ilog2(mm->chunk_size);
>>> + min_page_size = size;
>>> +
>>> + pages = size >> ilog2(mm->chunk_size);
>>> + if (pages > lpfn)
>>> + lpfn = pages;
>>> }
>>>
>>> if (size > mm->size) {
>>> @@ -73,34 +80,16 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
>>>
>>> n_pages = size >> ilog2(mm->chunk_size);
>>>
>>> - do {
>>> - struct drm_buddy_block *block;
>>> - unsigned int order;
>>> -
>>> - order = fls(n_pages) - 1;
>>> - GEM_BUG_ON(order > mm->max_order);
>>> - GEM_BUG_ON(order < min_order);
>>> -
>>> - do {
>>> - mutex_lock(&bman->lock);
>>> - block = drm_buddy_alloc_blocks(mm, order);
>>> - mutex_unlock(&bman->lock);
>>> - if (!IS_ERR(block))
>>> - break;
>>> -
>>> - if (order-- == min_order) {
>>> - err = -ENOSPC;
>>> - goto err_free_blocks;
>>> - }
>>> - } while (1);
>>> -
>>> - n_pages -= BIT(order);
>>> -
>>> - list_add_tail(&block->link, &bman_res->blocks);
>>> -
>>> - if (!n_pages)
>>> - break;
>>> - } while (1);
>>> + mutex_lock(&bman->lock);
>>> + err = drm_buddy_alloc_blocks(mm, (u64)place->fpfn << PAGE_SHIFT,
>>> + (u64)lpfn << PAGE_SHIFT,
>>> + (u64)n_pages << PAGE_SHIFT,
>>> + min_page_size,
>>> + &bman_res->blocks,
>>> + bman_res->flags);
>>> + mutex_unlock(&bman->lock);
>>> + if (unlikely(err))
>>> + goto err_free_blocks;
>>>
>>> *res = &bman_res->base;
>>> return 0;
>>> @@ -268,12 +257,16 @@ int i915_ttm_buddy_man_reserve(struct ttm_resource_manager *man,
>>> {
>>> struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);
>>> struct drm_buddy *mm = &bman->mm;
>>> + unsigned long flags = 0;
>>> int ret;
>>>
>>> mutex_lock(&bman->lock);
>>> - ret = drm_buddy_alloc_range(mm, &bman->reserved, start, size);
>>> + ret = drm_buddy_alloc_blocks(mm, start,
>>> + start + size,
>>> + size, mm->chunk_size,
>>> + &bman->reserved,
>>> + flags);
>>> mutex_unlock(&bman->lock);
>>>
>>> return ret;
>>> }
>>> -
>>> diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
>>> index 312077941411..72c90b432e87 100644
>>> --- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
>>> +++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
>>> @@ -20,6 +20,7 @@ struct drm_buddy;
>>> *
>>> * @base: struct ttm_resource base class we extend
>>> * @blocks: the list of struct i915_buddy_block for this resource/allocation
>>> + * @flags: DRM_BUDDY_*_ALLOCATION flags
>>> * @mm: the struct i915_buddy_mm for this resource
>>> *
>>> * Extends the struct ttm_resource to manage an address space allocation with
>>> @@ -28,6 +29,7 @@ struct drm_buddy;
>>> struct i915_ttm_buddy_resource {
>>> struct ttm_resource base;
>>> struct list_head blocks;
>>> + unsigned long flags;
>>> struct drm_buddy *mm;
>>> };
>>>
>>> diff --git a/include/drm/drm_buddy.h b/include/drm/drm_buddy.h
>>> index f524db152413..1f2435426c69 100644
>>> --- a/include/drm/drm_buddy.h
>>> +++ b/include/drm/drm_buddy.h
>>> @@ -131,12 +131,11 @@ int drm_buddy_init(struct drm_buddy *mm, u64 size, u64 chunk_size);
>>>
>>> void drm_buddy_fini(struct drm_buddy *mm);
>>>
>>> -struct drm_buddy_block *
>>> -drm_buddy_alloc_blocks(struct drm_buddy *mm, unsigned int order);
>>> -
>>> -int drm_buddy_alloc_range(struct drm_buddy *mm,
>>> - struct list_head *blocks,
>>> - u64 start, u64 size);
>>> +int drm_buddy_alloc_blocks(struct drm_buddy *mm,
>>> + u64 start, u64 end, u64 size,
>>> + u64 min_page_size,
>>> + struct list_head *blocks,
>>> + unsigned long flags);
>>>
>>> void drm_buddy_free_block(struct drm_buddy *mm, struct drm_buddy_block *block);
>>>
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