Re: [PATCH v12] drm/amdgpu: add drm buddy support to amdgpu

[Christian König <christian.koenig@xxxxxxx>]

Am 07.04.22 um 07:46 schrieb Arunpravin Paneer Selvam:
> - Switch to drm buddy allocator
> - Add resource cursor support for drm buddy
>
> v2(Matthew Auld):
>    - replace spinlock with mutex as we call kmem_cache_zalloc
>      (..., GFP_KERNEL) in drm_buddy_alloc() function
>
>    - lock drm_buddy_block_trim() function as it calls
>      mark_free/mark_split are all globally visible
>
> v3(Matthew Auld):
>    - remove trim method error handling as we address the failure case
>      at drm_buddy_block_trim() function
>
> v4:
>    - fix warnings reported by kernel test robot <lkp@xxxxxxxxx>
>
> v5:
>    - fix merge conflict issue
>
> v6:
>    - fix warnings reported by kernel test robot <lkp@xxxxxxxxx>
>
> v7:
>    - remove DRM_BUDDY_RANGE_ALLOCATION flag usage
>
> v8:
>    - keep DRM_BUDDY_RANGE_ALLOCATION flag usage
>    - resolve conflicts created by drm/amdgpu: remove VRAM accounting v2
>
> v9(Christian):
>    - merged the below patch
>       - drm/amdgpu: move vram inline functions into a header
>    - rename label name as fallback
>    - move struct amdgpu_vram_mgr to amdgpu_vram_mgr.h
>    - remove unnecessary flags from struct amdgpu_vram_reservation
>    - rewrite block NULL check condition
>    - change else style as per coding standard
>    - rewrite the node max size
>    - add a helper function to fetch the first entry from the list
>
> v10(Christian):
>     - rename amdgpu_get_node() function name as amdgpu_vram_mgr_first_block
>
> v11:
>     - if size is not aligned with min_page_size, enable is_contiguous flag,
>       therefore, the size round up to the power of two and trimmed to the
>       original size.
> v12:
>     - rename the function names having prefix as amdgpu_vram_mgr_*()
>     - modify the round_up() logic conforming to contiguous flag enablement
>       or if size is not aligned to min_block_size
>     - modify the trim logic
>     - rename node as block wherever applicable
>
> Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@xxxxxxx>

Acked-by: Christian König <christian.koenig@xxxxxxx>

I don't have time for a detailed in depth review, but this has seen 
enough iterations that I trust it to work fine.

Please check if the drm_buddy work has already backmerged into 
amd-staging-drm-next. If not maybe ping Alex when that is planned or 
alternatively I can push it through drm-misc-next.

Thanks,
Christian.

> ---
>   drivers/gpu/drm/Kconfig                       |   1 +
>   .../gpu/drm/amd/amdgpu/amdgpu_res_cursor.h    |  97 ++++-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h       |  10 +-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c  | 359 ++++++++++--------
>   4 files changed, 291 insertions(+), 176 deletions(-)
>
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index f1422bee3dcc..5133c3f028ab 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -280,6 +280,7 @@ config DRM_AMDGPU
>   	select HWMON
>   	select BACKLIGHT_CLASS_DEVICE
>   	select INTERVAL_TREE
> +	select DRM_BUDDY
>   	help
>   	  Choose this option if you have a recent AMD Radeon graphics card.
>   
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h
> index acfa207cf970..6546552e596c 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h
> @@ -30,12 +30,15 @@
>   #include <drm/ttm/ttm_resource.h>
>   #include <drm/ttm/ttm_range_manager.h>
>   
> +#include "amdgpu_vram_mgr.h"
> +
>   /* state back for walking over vram_mgr and gtt_mgr allocations */
>   struct amdgpu_res_cursor {
>   	uint64_t		start;
>   	uint64_t		size;
>   	uint64_t		remaining;
> -	struct drm_mm_node	*node;
> +	void			*node;
> +	uint32_t		mem_type;
>   };
>   
>   /**
> @@ -52,27 +55,63 @@ static inline void amdgpu_res_first(struct ttm_resource *res,
>   				    uint64_t start, uint64_t size,
>   				    struct amdgpu_res_cursor *cur)
>   {
> +	struct drm_buddy_block *block;
> +	struct list_head *head, *next;
>   	struct drm_mm_node *node;
>   
> -	if (!res || res->mem_type == TTM_PL_SYSTEM) {
> -		cur->start = start;
> -		cur->size = size;
> -		cur->remaining = size;
> -		cur->node = NULL;
> -		WARN_ON(res && start + size > res->num_pages << PAGE_SHIFT);
> -		return;
> -	}
> +	if (!res)
> +		goto fallback;
>   
>   	BUG_ON(start + size > res->num_pages << PAGE_SHIFT);
>   
> -	node = to_ttm_range_mgr_node(res)->mm_nodes;
> -	while (start >= node->size << PAGE_SHIFT)
> -		start -= node++->size << PAGE_SHIFT;
> +	cur->mem_type = res->mem_type;
> +
> +	switch (cur->mem_type) {
> +	case TTM_PL_VRAM:
> +		head = &to_amdgpu_vram_mgr_resource(res)->blocks;
> +
> +		block = list_first_entry_or_null(head,
> +						 struct drm_buddy_block,
> +						 link);
> +		if (!block)
> +			goto fallback;
> +
> +		while (start >= amdgpu_vram_mgr_block_size(block)) {
> +			start -= amdgpu_vram_mgr_block_size(block);
> +
> +			next = block->link.next;
> +			if (next != head)
> +				block = list_entry(next, struct drm_buddy_block, link);
> +		}
> +
> +		cur->start = amdgpu_vram_mgr_block_start(block) + start;
> +		cur->size = min(amdgpu_vram_mgr_block_size(block) - start, size);
> +		cur->remaining = size;
> +		cur->node = block;
> +		break;
> +	case TTM_PL_TT:
> +		node = to_ttm_range_mgr_node(res)->mm_nodes;
> +		while (start >= node->size << PAGE_SHIFT)
> +			start -= node++->size << PAGE_SHIFT;
> +
> +		cur->start = (node->start << PAGE_SHIFT) + start;
> +		cur->size = min((node->size << PAGE_SHIFT) - start, size);
> +		cur->remaining = size;
> +		cur->node = node;
> +		break;
> +	default:
> +		goto fallback;
> +	}
>   
> -	cur->start = (node->start << PAGE_SHIFT) + start;
> -	cur->size = min((node->size << PAGE_SHIFT) - start, size);
> +	return;
> +
> +fallback:
> +	cur->start = start;
> +	cur->size = size;
>   	cur->remaining = size;
> -	cur->node = node;
> +	cur->node = NULL;
> +	WARN_ON(res && start + size > res->num_pages << PAGE_SHIFT);
> +	return;
>   }
>   
>   /**
> @@ -85,7 +124,9 @@ static inline void amdgpu_res_first(struct ttm_resource *res,
>    */
>   static inline void amdgpu_res_next(struct amdgpu_res_cursor *cur, uint64_t size)
>   {
> -	struct drm_mm_node *node = cur->node;
> +	struct drm_buddy_block *block;
> +	struct drm_mm_node *node;
> +	struct list_head *next;
>   
>   	BUG_ON(size > cur->remaining);
>   
> @@ -99,9 +140,27 @@ static inline void amdgpu_res_next(struct amdgpu_res_cursor *cur, uint64_t size)
>   		return;
>   	}
>   
> -	cur->node = ++node;
> -	cur->start = node->start << PAGE_SHIFT;
> -	cur->size = min(node->size << PAGE_SHIFT, cur->remaining);
> +	switch (cur->mem_type) {
> +	case TTM_PL_VRAM:
> +		block = cur->node;
> +
> +		next = block->link.next;
> +		block = list_entry(next, struct drm_buddy_block, link);
> +
> +		cur->node = block;
> +		cur->start = amdgpu_vram_mgr_block_start(block);
> +		cur->size = min(amdgpu_vram_mgr_block_size(block), cur->remaining);
> +		break;
> +	case TTM_PL_TT:
> +		node = cur->node;
> +
> +		cur->node = ++node;
> +		cur->start = node->start << PAGE_SHIFT;
> +		cur->size = min(node->size << PAGE_SHIFT, cur->remaining);
> +		break;
> +	default:
> +		return;
> +	}
>   }
>   
>   #endif
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
> index 9120ae80ef52..6a70818039dd 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
> @@ -26,6 +26,7 @@
>   
>   #include <linux/dma-direction.h>
>   #include <drm/gpu_scheduler.h>
> +#include "amdgpu_vram_mgr.h"
>   #include "amdgpu.h"
>   
>   #define AMDGPU_PL_GDS		(TTM_PL_PRIV + 0)
> @@ -38,15 +39,6 @@
>   
>   #define AMDGPU_POISON	0xd0bed0be
>   
> -struct amdgpu_vram_mgr {
> -	struct ttm_resource_manager manager;
> -	struct drm_mm mm;
> -	spinlock_t lock;
> -	struct list_head reservations_pending;
> -	struct list_head reserved_pages;
> -	atomic64_t vis_usage;
> -};
> -
>   struct amdgpu_gtt_mgr {
>   	struct ttm_resource_manager manager;
>   	struct drm_mm mm;
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> index 0a7611648573..49e4092f447f 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> @@ -32,8 +32,10 @@
>   #include "atom.h"
>   
>   struct amdgpu_vram_reservation {
> -	struct list_head node;
> -	struct drm_mm_node mm_node;
> +	u64 start;
> +	u64 size;
> +	struct list_head allocated;
> +	struct list_head blocks;
>   };
>   
>   static inline struct amdgpu_vram_mgr *
> @@ -186,18 +188,18 @@ const struct attribute_group amdgpu_vram_mgr_attr_group = {
>   };
>   
>   /**
> - * amdgpu_vram_mgr_vis_size - Calculate visible node size
> + * amdgpu_vram_mgr_vis_size - Calculate visible block size
>    *
>    * @adev: amdgpu_device pointer
> - * @node: MM node structure
> + * @block: DRM BUDDY block structure
>    *
> - * Calculate how many bytes of the MM node are inside visible VRAM
> + * Calculate how many bytes of the DRM BUDDY block are inside visible VRAM
>    */
>   static u64 amdgpu_vram_mgr_vis_size(struct amdgpu_device *adev,
> -				    struct drm_mm_node *node)
> +				    struct drm_buddy_block *block)
>   {
> -	uint64_t start = node->start << PAGE_SHIFT;
> -	uint64_t end = (node->size + node->start) << PAGE_SHIFT;
> +	u64 start = amdgpu_vram_mgr_block_start(block);
> +	u64 end = start + amdgpu_vram_mgr_block_size(block);
>   
>   	if (start >= adev->gmc.visible_vram_size)
>   		return 0;
> @@ -218,9 +220,9 @@ u64 amdgpu_vram_mgr_bo_visible_size(struct amdgpu_bo *bo)
>   {
>   	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
>   	struct ttm_resource *res = bo->tbo.resource;
> -	unsigned pages = res->num_pages;
> -	struct drm_mm_node *mm;
> -	u64 usage;
> +	struct amdgpu_vram_mgr_resource *vres = to_amdgpu_vram_mgr_resource(res);
> +	struct drm_buddy_block *block;
> +	u64 usage = 0;
>   
>   	if (amdgpu_gmc_vram_full_visible(&adev->gmc))
>   		return amdgpu_bo_size(bo);
> @@ -228,9 +230,8 @@ u64 amdgpu_vram_mgr_bo_visible_size(struct amdgpu_bo *bo)
>   	if (res->start >= adev->gmc.visible_vram_size >> PAGE_SHIFT)
>   		return 0;
>   
> -	mm = &container_of(res, struct ttm_range_mgr_node, base)->mm_nodes[0];
> -	for (usage = 0; pages; pages -= mm->size, mm++)
> -		usage += amdgpu_vram_mgr_vis_size(adev, mm);
> +	list_for_each_entry(block, &vres->blocks, link)
> +		usage += amdgpu_vram_mgr_vis_size(adev, block);
>   
>   	return usage;
>   }
> @@ -240,23 +241,30 @@ static void amdgpu_vram_mgr_do_reserve(struct ttm_resource_manager *man)
>   {
>   	struct amdgpu_vram_mgr *mgr = to_vram_mgr(man);
>   	struct amdgpu_device *adev = to_amdgpu_device(mgr);
> -	struct drm_mm *mm = &mgr->mm;
> +	struct drm_buddy *mm = &mgr->mm;
>   	struct amdgpu_vram_reservation *rsv, *temp;
> +	struct drm_buddy_block *block;
>   	uint64_t vis_usage;
>   
> -	list_for_each_entry_safe(rsv, temp, &mgr->reservations_pending, node) {
> -		if (drm_mm_reserve_node(mm, &rsv->mm_node))
> +	list_for_each_entry_safe(rsv, temp, &mgr->reservations_pending, blocks) {
> +		if (drm_buddy_alloc_blocks(mm, rsv->start, rsv->start + rsv->size,
> +					   rsv->size, mm->chunk_size, &rsv->allocated,
> +					   DRM_BUDDY_RANGE_ALLOCATION))
> +			continue;
> +
> +		block = amdgpu_vram_mgr_first_block(&rsv->allocated);
> +		if (!block)
>   			continue;
>   
>   		dev_dbg(adev->dev, "Reservation 0x%llx - %lld, Succeeded\n",
> -			rsv->mm_node.start, rsv->mm_node.size);
> +			rsv->start, rsv->size);
>   
> -		vis_usage = amdgpu_vram_mgr_vis_size(adev, &rsv->mm_node);
> +		vis_usage = amdgpu_vram_mgr_vis_size(adev, block);
>   		atomic64_add(vis_usage, &mgr->vis_usage);
>   		spin_lock(&man->bdev->lru_lock);
> -		man->usage += rsv->mm_node.size << PAGE_SHIFT;
> +		man->usage += rsv->size;
>   		spin_unlock(&man->bdev->lru_lock);
> -		list_move(&rsv->node, &mgr->reserved_pages);
> +		list_move(&rsv->blocks, &mgr->reserved_pages);
>   	}
>   }
>   
> @@ -278,14 +286,16 @@ int amdgpu_vram_mgr_reserve_range(struct amdgpu_vram_mgr *mgr,
>   	if (!rsv)
>   		return -ENOMEM;
>   
> -	INIT_LIST_HEAD(&rsv->node);
> -	rsv->mm_node.start = start >> PAGE_SHIFT;
> -	rsv->mm_node.size = size >> PAGE_SHIFT;
> +	INIT_LIST_HEAD(&rsv->allocated);
> +	INIT_LIST_HEAD(&rsv->blocks);
>   
> -	spin_lock(&mgr->lock);
> -	list_add_tail(&rsv->node, &mgr->reservations_pending);
> +	rsv->start = start;
> +	rsv->size = size;
> +
> +	mutex_lock(&mgr->lock);
> +	list_add_tail(&rsv->blocks, &mgr->reservations_pending);
>   	amdgpu_vram_mgr_do_reserve(&mgr->manager);
> -	spin_unlock(&mgr->lock);
> +	mutex_unlock(&mgr->lock);
>   
>   	return 0;
>   }
> @@ -307,19 +317,19 @@ int amdgpu_vram_mgr_query_page_status(struct amdgpu_vram_mgr *mgr,
>   	struct amdgpu_vram_reservation *rsv;
>   	int ret;
>   
> -	spin_lock(&mgr->lock);
> +	mutex_lock(&mgr->lock);
>   
> -	list_for_each_entry(rsv, &mgr->reservations_pending, node) {
> -		if ((rsv->mm_node.start <= start) &&
> -		    (start < (rsv->mm_node.start + rsv->mm_node.size))) {
> +	list_for_each_entry(rsv, &mgr->reservations_pending, blocks) {
> +		if (rsv->start <= start &&
> +		    (start < (rsv->start + rsv->size))) {
>   			ret = -EBUSY;
>   			goto out;
>   		}
>   	}
>   
> -	list_for_each_entry(rsv, &mgr->reserved_pages, node) {
> -		if ((rsv->mm_node.start <= start) &&
> -		    (start < (rsv->mm_node.start + rsv->mm_node.size))) {
> +	list_for_each_entry(rsv, &mgr->reserved_pages, blocks) {
> +		if (rsv->start <= start &&
> +		    (start < (rsv->start + rsv->size))) {
>   			ret = 0;
>   			goto out;
>   		}
> @@ -327,32 +337,10 @@ int amdgpu_vram_mgr_query_page_status(struct amdgpu_vram_mgr *mgr,
>   
>   	ret = -ENOENT;
>   out:
> -	spin_unlock(&mgr->lock);
> +	mutex_unlock(&mgr->lock);
>   	return ret;
>   }
>   
> -/**
> - * amdgpu_vram_mgr_virt_start - update virtual start address
> - *
> - * @mem: ttm_resource to update
> - * @node: just allocated node
> - *
> - * Calculate a virtual BO start address to easily check if everything is CPU
> - * accessible.
> - */
> -static void amdgpu_vram_mgr_virt_start(struct ttm_resource *mem,
> -				       struct drm_mm_node *node)
> -{
> -	unsigned long start;
> -
> -	start = node->start + node->size;
> -	if (start > mem->num_pages)
> -		start -= mem->num_pages;
> -	else
> -		start = 0;
> -	mem->start = max(mem->start, start);
> -}
> -
>   /**
>    * amdgpu_vram_mgr_new - allocate new ranges
>    *
> @@ -368,46 +356,44 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
>   			       const struct ttm_place *place,
>   			       struct ttm_resource **res)
>   {
> -	unsigned long lpfn, num_nodes, pages_per_node, pages_left, pages;
> +	u64 vis_usage = 0, max_bytes, cur_size, min_block_size;
>   	struct amdgpu_vram_mgr *mgr = to_vram_mgr(man);
>   	struct amdgpu_device *adev = to_amdgpu_device(mgr);
> -	uint64_t vis_usage = 0, mem_bytes, max_bytes;
> -	struct ttm_range_mgr_node *node;
> -	struct drm_mm *mm = &mgr->mm;
> -	enum drm_mm_insert_mode mode;
> -	unsigned i;
> +	struct amdgpu_vram_mgr_resource *vres;
> +	u64 size, remaining_size, lpfn, fpfn;
> +	struct drm_buddy *mm = &mgr->mm;
> +	struct drm_buddy_block *block;
> +	unsigned long pages_per_block;
>   	int r;
>   
> -	lpfn = place->lpfn;
> +	lpfn = place->lpfn << PAGE_SHIFT;
>   	if (!lpfn)
> -		lpfn = man->size >> PAGE_SHIFT;
> +		lpfn = man->size;
> +
> +	fpfn = place->fpfn << PAGE_SHIFT;
>   
>   	max_bytes = adev->gmc.mc_vram_size;
>   	if (tbo->type != ttm_bo_type_kernel)
>   		max_bytes -= AMDGPU_VM_RESERVED_VRAM;
>   
> -	mem_bytes = tbo->base.size;
>   	if (place->flags & TTM_PL_FLAG_CONTIGUOUS) {
> -		pages_per_node = ~0ul;
> -		num_nodes = 1;
> +		pages_per_block = ~0ul;
>   	} else {
>   #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> -		pages_per_node = HPAGE_PMD_NR;
> +		pages_per_block = HPAGE_PMD_NR;
>   #else
>   		/* default to 2MB */
> -		pages_per_node = 2UL << (20UL - PAGE_SHIFT);
> +		pages_per_block = 2UL << (20UL - PAGE_SHIFT);
>   #endif
> -		pages_per_node = max_t(uint32_t, pages_per_node,
> -				       tbo->page_alignment);
> -		num_nodes = DIV_ROUND_UP_ULL(PFN_UP(mem_bytes), pages_per_node);
> +		pages_per_block = max_t(uint32_t, pages_per_block,
> +					tbo->page_alignment);
>   	}
>   
> -	node = kvmalloc(struct_size(node, mm_nodes, num_nodes),
> -			GFP_KERNEL | __GFP_ZERO);
> -	if (!node)
> +	vres = kzalloc(sizeof(*vres), GFP_KERNEL);
> +	if (!vres)
>   		return -ENOMEM;
>   
> -	ttm_resource_init(tbo, place, &node->base);
> +	ttm_resource_init(tbo, place, &vres->base);
>   
>   	/* bail out quickly if there's likely not enough VRAM for this BO */
>   	if (ttm_resource_manager_usage(man) > max_bytes) {
> @@ -415,66 +401,130 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
>   		goto error_fini;
>   	}
>   
> -	mode = DRM_MM_INSERT_BEST;
> +	INIT_LIST_HEAD(&vres->blocks);
> +
>   	if (place->flags & TTM_PL_FLAG_TOPDOWN)
> -		mode = DRM_MM_INSERT_HIGH;
> -
> -	pages_left = node->base.num_pages;
> -
> -	/* Limit maximum size to 2GB due to SG table limitations */
> -	pages = min(pages_left, 2UL << (30 - PAGE_SHIFT));
> -
> -	i = 0;
> -	spin_lock(&mgr->lock);
> -	while (pages_left) {
> -		uint32_t alignment = tbo->page_alignment;
> -
> -		if (pages >= pages_per_node)
> -			alignment = pages_per_node;
> -
> -		r = drm_mm_insert_node_in_range(mm, &node->mm_nodes[i], pages,
> -						alignment, 0, place->fpfn,
> -						lpfn, mode);
> -		if (unlikely(r)) {
> -			if (pages > pages_per_node) {
> -				if (is_power_of_2(pages))
> -					pages = pages / 2;
> -				else
> -					pages = rounddown_pow_of_two(pages);
> -				continue;
> +		vres->flags |= DRM_BUDDY_TOPDOWN_ALLOCATION;
> +
> +	if (fpfn || lpfn != man->size)
> +		/* Allocate blocks in desired range */
> +		vres->flags |= DRM_BUDDY_RANGE_ALLOCATION;
> +
> +	remaining_size = vres->base.num_pages << PAGE_SHIFT;
> +
> +	mutex_lock(&mgr->lock);
> +	while (remaining_size) {
> +		if (tbo->page_alignment)
> +			min_block_size = tbo->page_alignment << PAGE_SHIFT;
> +		else
> +			min_block_size = mgr->default_page_size;
> +
> +		BUG_ON(min_block_size < mm->chunk_size);
> +
> +		/* Limit maximum size to 2GiB due to SG table limitations */
> +		size = min(remaining_size, 2ULL << 30);
> +
> +		if (size >= pages_per_block << PAGE_SHIFT)
> +			min_block_size = pages_per_block << PAGE_SHIFT;
> +
> +		cur_size = size;
> +
> +		if (fpfn + size != place->lpfn << PAGE_SHIFT) {
> +			/*
> +			 * Except for actual range allocation, modify the size and
> +			 * min_block_size conforming to continuous flag enablement
> +			 */
> +			if (place->flags & TTM_PL_FLAG_CONTIGUOUS) {
> +				size = roundup_pow_of_two(size);
> +				min_block_size = size;
> +			/*
> +			 * Modify the size value if size is not
> +			 * aligned with min_block_size
> +			 */
> +			} else if (!IS_ALIGNED(size, min_block_size)) {
> +				size = round_up(size, min_block_size);
>   			}
> -			goto error_free;
>   		}
>   
> -		vis_usage += amdgpu_vram_mgr_vis_size(adev, &node->mm_nodes[i]);
> -		amdgpu_vram_mgr_virt_start(&node->base, &node->mm_nodes[i]);
> -		pages_left -= pages;
> -		++i;
> +		r = drm_buddy_alloc_blocks(mm, fpfn,
> +					   lpfn,
> +					   size,
> +					   min_block_size,
> +					   &vres->blocks,
> +					   vres->flags);
> +		if (unlikely(r))
> +			goto error_free_blocks;
> +
> +		if (size > remaining_size)
> +			remaining_size = 0;
> +		else
> +			remaining_size -= size;
> +	}
> +	mutex_unlock(&mgr->lock);
> +
> +	if (cur_size != size) {
> +		struct drm_buddy_block *block;
> +		struct list_head *trim_list;
> +		u64 original_size;
> +		LIST_HEAD(temp);
> +
> +		trim_list = &vres->blocks;
> +		original_size = vres->base.num_pages << PAGE_SHIFT;
> +
> +		/*
> +		 * If size value is rounded up to min_block_size, trim the last
> +		 * block to the required size
> +		 */
> +		if (!list_is_singular(&vres->blocks)) {
> +			block = list_last_entry(&vres->blocks, typeof(*block), link);
> +			list_move_tail(&block->link, &temp);
> +			trim_list = &temp;
> +			/*
> +			 * Compute the original_size value by subtracting the
> +			 * last block size with (aligned size - original size)
> +			 */
> +			original_size = amdgpu_vram_mgr_block_size(block) - (size - cur_size);
> +		}
>   
> -		if (pages > pages_left)
> -			pages = pages_left;
> +		mutex_lock(&mgr->lock);
> +		drm_buddy_block_trim(mm,
> +				     original_size,
> +				     trim_list);
> +		mutex_unlock(&mgr->lock);
> +
> +		if (!list_empty(&temp))
> +			list_splice_tail(trim_list, &vres->blocks);
> +	}
> +
> +	list_for_each_entry(block, &vres->blocks, link)
> +		vis_usage += amdgpu_vram_mgr_vis_size(adev, block);
> +
> +	block = amdgpu_vram_mgr_first_block(&vres->blocks);
> +	if (!block) {
> +		r = -EINVAL;
> +		goto error_fini;
>   	}
> -	spin_unlock(&mgr->lock);
>   
> -	if (i == 1)
> -		node->base.placement |= TTM_PL_FLAG_CONTIGUOUS;
> +	vres->base.start = amdgpu_vram_mgr_block_start(block) >> PAGE_SHIFT;
> +
> +	if (amdgpu_is_vram_mgr_blocks_contiguous(&vres->blocks))
> +		vres->base.placement |= TTM_PL_FLAG_CONTIGUOUS;
>   
>   	if (adev->gmc.xgmi.connected_to_cpu)
> -		node->base.bus.caching = ttm_cached;
> +		vres->base.bus.caching = ttm_cached;
>   	else
> -		node->base.bus.caching = ttm_write_combined;
> +		vres->base.bus.caching = ttm_write_combined;
>   
>   	atomic64_add(vis_usage, &mgr->vis_usage);
> -	*res = &node->base;
> +	*res = &vres->base;
>   	return 0;
>   
> -error_free:
> -	while (i--)
> -		drm_mm_remove_node(&node->mm_nodes[i]);
> -	spin_unlock(&mgr->lock);
> +error_free_blocks:
> +	drm_buddy_free_list(mm, &vres->blocks);
> +	mutex_unlock(&mgr->lock);
>   error_fini:
> -	ttm_resource_fini(man, &node->base);
> -	kvfree(node);
> +	ttm_resource_fini(man, &vres->base);
> +	kfree(vres);
>   
>   	return r;
>   }
> @@ -490,27 +540,26 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
>   static void amdgpu_vram_mgr_del(struct ttm_resource_manager *man,
>   				struct ttm_resource *res)
>   {
> -	struct ttm_range_mgr_node *node = to_ttm_range_mgr_node(res);
> +	struct amdgpu_vram_mgr_resource *vres = to_amdgpu_vram_mgr_resource(res);
>   	struct amdgpu_vram_mgr *mgr = to_vram_mgr(man);
>   	struct amdgpu_device *adev = to_amdgpu_device(mgr);
> +	struct drm_buddy *mm = &mgr->mm;
> +	struct drm_buddy_block *block;
>   	uint64_t vis_usage = 0;
> -	unsigned i, pages;
>   
> -	spin_lock(&mgr->lock);
> -	for (i = 0, pages = res->num_pages; pages;
> -	     pages -= node->mm_nodes[i].size, ++i) {
> -		struct drm_mm_node *mm = &node->mm_nodes[i];
> +	mutex_lock(&mgr->lock);
> +	list_for_each_entry(block, &vres->blocks, link)
> +		vis_usage += amdgpu_vram_mgr_vis_size(adev, block);
>   
> -		drm_mm_remove_node(mm);
> -		vis_usage += amdgpu_vram_mgr_vis_size(adev, mm);
> -	}
>   	amdgpu_vram_mgr_do_reserve(man);
> -	spin_unlock(&mgr->lock);
> +
> +	drm_buddy_free_list(mm, &vres->blocks);
> +	mutex_unlock(&mgr->lock);
>   
>   	atomic64_sub(vis_usage, &mgr->vis_usage);
>   
>   	ttm_resource_fini(man, res);
> -	kvfree(node);
> +	kfree(vres);
>   }
>   
>   /**
> @@ -542,7 +591,7 @@ int amdgpu_vram_mgr_alloc_sgt(struct amdgpu_device *adev,
>   	if (!*sgt)
>   		return -ENOMEM;
>   
> -	/* Determine the number of DRM_MM nodes to export */
> +	/* Determine the number of DRM_BUDDY blocks to export */
>   	amdgpu_res_first(res, offset, length, &cursor);
>   	while (cursor.remaining) {
>   		num_entries++;
> @@ -558,10 +607,10 @@ int amdgpu_vram_mgr_alloc_sgt(struct amdgpu_device *adev,
>   		sg->length = 0;
>   
>   	/*
> -	 * Walk down DRM_MM nodes to populate scatterlist nodes
> -	 * @note: Use iterator api to get first the DRM_MM node
> +	 * Walk down DRM_BUDDY blocks to populate scatterlist nodes
> +	 * @note: Use iterator api to get first the DRM_BUDDY block
>   	 * and the number of bytes from it. Access the following
> -	 * DRM_MM node(s) if more buffer needs to exported
> +	 * DRM_BUDDY block(s) if more buffer needs to exported
>   	 */
>   	amdgpu_res_first(res, offset, length, &cursor);
>   	for_each_sgtable_sg((*sgt), sg, i) {
> @@ -648,13 +697,22 @@ static void amdgpu_vram_mgr_debug(struct ttm_resource_manager *man,
>   				  struct drm_printer *printer)
>   {
>   	struct amdgpu_vram_mgr *mgr = to_vram_mgr(man);
> +	struct drm_buddy *mm = &mgr->mm;
> +	struct drm_buddy_block *block;
>   
>   	drm_printf(printer, "  vis usage:%llu\n",
>   		   amdgpu_vram_mgr_vis_usage(mgr));
>   
> -	spin_lock(&mgr->lock);
> -	drm_mm_print(&mgr->mm, printer);
> -	spin_unlock(&mgr->lock);
> +	mutex_lock(&mgr->lock);
> +	drm_printf(printer, "default_page_size: %lluKiB\n",
> +		   mgr->default_page_size >> 10);
> +
> +	drm_buddy_print(mm, printer);
> +
> +	drm_printf(printer, "reserved:\n");
> +	list_for_each_entry(block, &mgr->reserved_pages, link)
> +		drm_buddy_block_print(mm, block, printer);
> +	mutex_unlock(&mgr->lock);
>   }
>   
>   static const struct ttm_resource_manager_func amdgpu_vram_mgr_func = {
> @@ -674,16 +732,21 @@ int amdgpu_vram_mgr_init(struct amdgpu_device *adev)
>   {
>   	struct amdgpu_vram_mgr *mgr = &adev->mman.vram_mgr;
>   	struct ttm_resource_manager *man = &mgr->manager;
> +	int err;
>   
>   	ttm_resource_manager_init(man, &adev->mman.bdev,
>   				  adev->gmc.real_vram_size);
>   
>   	man->func = &amdgpu_vram_mgr_func;
>   
> -	drm_mm_init(&mgr->mm, 0, man->size >> PAGE_SHIFT);
> -	spin_lock_init(&mgr->lock);
> +	err = drm_buddy_init(&mgr->mm, man->size, PAGE_SIZE);
> +	if (err)
> +		return err;
> +
> +	mutex_init(&mgr->lock);
>   	INIT_LIST_HEAD(&mgr->reservations_pending);
>   	INIT_LIST_HEAD(&mgr->reserved_pages);
> +	mgr->default_page_size = PAGE_SIZE;
>   
>   	ttm_set_driver_manager(&adev->mman.bdev, TTM_PL_VRAM, &mgr->manager);
>   	ttm_resource_manager_set_used(man, true);
> @@ -711,16 +774,16 @@ void amdgpu_vram_mgr_fini(struct amdgpu_device *adev)
>   	if (ret)
>   		return;
>   
> -	spin_lock(&mgr->lock);
> -	list_for_each_entry_safe(rsv, temp, &mgr->reservations_pending, node)
> +	mutex_lock(&mgr->lock);
> +	list_for_each_entry_safe(rsv, temp, &mgr->reservations_pending, blocks)
>   		kfree(rsv);
>   
> -	list_for_each_entry_safe(rsv, temp, &mgr->reserved_pages, node) {
> -		drm_mm_remove_node(&rsv->mm_node);
> +	list_for_each_entry_safe(rsv, temp, &mgr->reserved_pages, blocks) {
> +		drm_buddy_free_list(&mgr->mm, &rsv->blocks);
>   		kfree(rsv);
>   	}
> -	drm_mm_takedown(&mgr->mm);
> -	spin_unlock(&mgr->lock);
> +	drm_buddy_fini(&mgr->mm);
> +	mutex_unlock(&mgr->lock);
>   
>   	ttm_resource_manager_cleanup(man);
>   	ttm_set_driver_manager(&adev->mman.bdev, TTM_PL_VRAM, NULL);
>
> base-commit: bc38e5d45dd513fa384bbedab3c0749f2e46771b