[PATCH 2/2] Add drm buddy manager support to amdgpu driver

Arunpravin Arunpravin.PaneerSelvam at amd.com
Mon Sep 20 19:21:10 UTC 2021


Replace drm_mm with drm buddy manager for
VRAM memory management

Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam at amd.com>
---
 .../gpu/drm/amd/amdgpu/amdgpu_res_cursor.h    |  78 +++++--
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h       |   3 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c  | 216 ++++++++++--------
 3 files changed, 189 insertions(+), 108 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h
index acfa207cf970..ba24052e9062 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h
@@ -30,12 +30,25 @@
 #include <drm/ttm/ttm_resource.h>
 #include <drm/ttm/ttm_range_manager.h>
 
+struct amdgpu_vram_mgr_node {
+	struct ttm_range_mgr_node tnode;
+	struct list_head blocks;
+};
+
+static inline struct amdgpu_vram_mgr_node *
+to_amdgpu_vram_mgr_node(struct ttm_resource *res)
+{
+	return container_of(container_of(res, struct ttm_range_mgr_node, base),
+			struct amdgpu_vram_mgr_node, tnode);
+}
+
 /* 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;
 };
 
 /**
@@ -52,8 +65,6 @@ static inline void amdgpu_res_first(struct ttm_resource *res,
 				    uint64_t start, uint64_t size,
 				    struct amdgpu_res_cursor *cur)
 {
-	struct drm_mm_node *node;
-
 	if (!res || res->mem_type == TTM_PL_SYSTEM) {
 		cur->start = start;
 		cur->size = size;
@@ -65,14 +76,39 @@ static inline void amdgpu_res_first(struct ttm_resource *res,
 
 	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;
+
+	if (cur->mem_type == TTM_PL_VRAM) {
+		struct drm_buddy_block *block;
+		struct list_head *head, *next;
+
+		head = &to_amdgpu_vram_mgr_node(res)->blocks;
+
+		block = list_first_entry_or_null(head, struct drm_buddy_block, link);
+		while (start >= block->size << PAGE_SHIFT) {
+			start -= block->size << PAGE_SHIFT;
+
+			next = block->link.next;
+			if (next != head)
+				block = list_entry(next, struct drm_buddy_block, link);
+		}
 
-	cur->start = (node->start << PAGE_SHIFT) + start;
-	cur->size = min((node->size << PAGE_SHIFT) - start, size);
-	cur->remaining = size;
-	cur->node = node;
+		cur->start = (block->start << PAGE_SHIFT) + start;
+		cur->size = min((block->size << PAGE_SHIFT) - start, size);
+		cur->remaining = size;
+		cur->node = block;
+	} else if (cur->mem_type == TTM_PL_TT) {
+		struct drm_mm_node *node;
+
+		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;
+	}
 }
 
 /**
@@ -85,8 +121,6 @@ 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;
-
 	BUG_ON(size > cur->remaining);
 
 	cur->remaining -= size;
@@ -99,9 +133,23 @@ 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);
+	if (cur->mem_type == TTM_PL_VRAM) {
+		struct drm_buddy_block *block = cur->node;
+		struct list_head *next;
+
+		next = block->link.next;
+		block = list_entry(next, struct drm_buddy_block, link);
+
+		cur->node = block;
+		cur->start = block->start << PAGE_SHIFT;
+		cur->size = min(block->size << PAGE_SHIFT, cur->remaining);
+	} else if (cur->mem_type == TTM_PL_TT) {
+		struct drm_mm_node *node = cur->node;
+
+		cur->node = ++node;
+		cur->start = node->start << PAGE_SHIFT;
+		cur->size = min(node->size << PAGE_SHIFT, cur->remaining);
+	}
 }
 
 #endif
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
index e69f3e8e06e5..96c8e8aaa0ee 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 <drm/drm_buddy.h>
 #include "amdgpu.h"
 
 #define AMDGPU_PL_GDS		(TTM_PL_PRIV + 0)
@@ -40,7 +41,7 @@
 
 struct amdgpu_vram_mgr {
 	struct ttm_resource_manager manager;
-	struct drm_mm mm;
+	struct drm_buddy_mm mm;
 	spinlock_t lock;
 	struct list_head reservations_pending;
 	struct list_head reserved_pages;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
index 7b2b0980ec41..de0c5f4cabaf 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
@@ -23,7 +23,9 @@
  */
 
 #include <linux/dma-mapping.h>
+#include <linux/list_sort.h>
 #include <drm/ttm/ttm_range_manager.h>
+#include <drm/drm_buddy.h>
 
 #include "amdgpu.h"
 #include "amdgpu_vm.h"
@@ -33,7 +35,7 @@
 
 struct amdgpu_vram_reservation {
 	struct list_head node;
-	struct drm_mm_node mm_node;
+	struct drm_buddy_block mm_node;
 };
 
 static inline struct amdgpu_vram_mgr *
@@ -196,10 +198,10 @@ const struct attribute_group amdgpu_vram_mgr_attr_group = {
  * Calculate how many bytes of the MM node 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;
+	uint64_t start = block->start << PAGE_SHIFT;
+	uint64_t end = (block->size + block->start) << PAGE_SHIFT;
 
 	if (start >= adev->gmc.visible_vram_size)
 		return 0;
@@ -220,8 +222,8 @@ 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;
+	struct amdgpu_vram_mgr_node *vnode = to_amdgpu_vram_mgr_node(res);
+	struct drm_buddy_block *block;
 	u64 usage;
 
 	if (amdgpu_gmc_vram_full_visible(&adev->gmc))
@@ -230,9 +232,8 @@ 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, &vnode->blocks, link)
+		usage += amdgpu_vram_mgr_vis_size(adev, block);
 
 	return usage;
 }
@@ -242,12 +243,15 @@ 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 *mm = &mgr->mm;
 	struct amdgpu_vram_reservation *rsv, *temp;
 	uint64_t vis_usage;
+	int r = 0;
 
 	list_for_each_entry_safe(rsv, temp, &mgr->reservations_pending, node) {
-		if (drm_mm_reserve_node(mm, &rsv->mm_node))
+		r = drm_buddy_alloc_range(mm, &rsv->node, rsv->mm_node.start, rsv->mm_node.size);
+
+		if (unlikely(r))
 			continue;
 
 		dev_dbg(adev->dev, "Reservation 0x%llx - %lld, Succeeded\n",
@@ -333,26 +337,16 @@ int amdgpu_vram_mgr_query_page_status(struct ttm_resource_manager *man,
 	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)
+static int sort_blocks(void *priv, const struct list_head *A,
+					const struct list_head *B)
 {
-	unsigned long start;
+	struct drm_buddy_block *a = list_entry(A, typeof(*a), link);
+	struct drm_buddy_block *b = list_entry(B, typeof(*b), link);
 
-	start = node->start + node->size;
-	if (start > mem->num_pages)
-		start -= mem->num_pages;
+	if (a->start < b->start)
+		return -1;
 	else
-		start = 0;
-	mem->start = max(mem->start, start);
+		return 1;
 }
 
 /**
@@ -370,15 +364,20 @@ 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;
+	unsigned long lpfn, pages_per_node, pages_left, pages;
 	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 amdgpu_vram_mgr_node *vnode;
+	struct drm_buddy_mm *mm = &mgr->mm;
 	struct ttm_range_mgr_node *node;
-	struct drm_mm *mm = &mgr->mm;
-	enum drm_mm_insert_mode mode;
+	enum drm_buddy_alloc_mode mode;
+	struct drm_buddy_block *block;
+	unsigned int visible_pfn;
+	bool bar_limit_enabled;
+	unsigned long n_pages;
 	unsigned i;
-	int r;
+	int r = 0;
 
 	lpfn = place->lpfn;
 	if (!lpfn)
@@ -395,10 +394,9 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
 		goto error_sub;
 	}
 
-	if (place->flags & TTM_PL_FLAG_CONTIGUOUS) {
+	if (place->flags & TTM_PL_FLAG_CONTIGUOUS)
 		pages_per_node = ~0ul;
-		num_nodes = 1;
-	} else {
+	else {
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 		pages_per_node = HPAGE_PMD_NR;
 #else
@@ -407,57 +405,97 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
 #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);
 	}
 
-	node = kvmalloc(struct_size(node, mm_nodes, num_nodes),
-			GFP_KERNEL | __GFP_ZERO);
-	if (!node) {
+	vnode = kzalloc(sizeof(*vnode), GFP_KERNEL);
+
+	if (!vnode) {
 		r = -ENOMEM;
 		goto error_sub;
 	}
 
+	node = &vnode->tnode;
+
 	ttm_resource_init(tbo, place, &node->base);
 
-	mode = DRM_MM_INSERT_BEST;
-	if (place->flags & TTM_PL_FLAG_TOPDOWN)
-		mode = DRM_MM_INSERT_HIGH;
+	bar_limit_enabled = !(amdgpu_gmc_vram_full_visible(&adev->gmc));
+
+	visible_pfn = adev->gmc.visible_vram_size >> PAGE_SHIFT;
+
+	mode = DRM_BUDDY_BOTTOM_UP;
+	if (!place->fpfn && lpfn == man->size &&
+					(place->flags & TTM_PL_FLAG_TOPDOWN))
+		/* Allocate blocks from CPU non-mappable (TOP-DOWN) region */
+		mode = DRM_BUDDY_TOP_DOWN;
+	else if (place->fpfn || (lpfn != man->size && lpfn != visible_pfn))
+		/* Allocate blocks in desired range */
+		mode = DRM_BUDDY_ALLOC_RANGE;
 
 	pages_left = node->base.num_pages;
 
 	/* Limit maximum size to 2GB due to SG table limitations */
 	pages = min(pages_left, 2UL << (30 - PAGE_SHIFT));
 
+	INIT_LIST_HEAD(&vnode->blocks);
+
 	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;
-			}
-			goto error_free;
-		}
+	if (mode == DRM_BUDDY_ALLOC_RANGE) {
+		r = drm_buddy_alloc_range(mm, &vnode->blocks,
+				(uint64_t)place->fpfn << PAGE_SHIFT, pages << PAGE_SHIFT);
+
+		if (unlikely(r))
+			goto error_free_res;
+	} else {
+		while (pages_left) {
+			if (pages >= pages_per_node)
+				pages = pages_per_node;
+
+			n_pages = pages;
+
+			if (place->flags & TTM_PL_FLAG_CONTIGUOUS)
+				n_pages = roundup_pow_of_two(n_pages);
+
+			do {
+				unsigned int order;
+
+				order = fls(n_pages) - 1;
+				BUG_ON(order > mm->max_order);
+
+				spin_lock(&mgr->lock);
+				block = drm_buddy_alloc(mm, order, bar_limit_enabled,
+									visible_pfn, mode);
+				spin_unlock(&mgr->lock);
 
-		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;
+				if (IS_ERR(block)) {
+					r = -ENOSPC;
+					goto error_free_blocks;
+				}
 
-		if (pages > pages_left)
-			pages = pages_left;
+				n_pages -= BIT(order);
+
+				list_add_tail(&block->link, &vnode->blocks);
+
+				if (!n_pages)
+					break;
+			} while (1);
+
+			pages_left -= pages;
+			++i;
+
+			if (pages > pages_left)
+				pages = pages_left;
+		}
 	}
+
+	spin_lock(&mgr->lock);
+	list_sort(NULL, &vnode->blocks, sort_blocks);
+
+	list_for_each_entry(block, &vnode->blocks, link)
+		vis_usage += amdgpu_vram_mgr_vis_size(adev, block);
+
+	block = list_first_entry_or_null(&vnode->blocks,
+			struct drm_buddy_block, link);
+	node->base.start = block->start;
 	spin_unlock(&mgr->lock);
 
 	if (i == 1)
@@ -472,12 +510,12 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
 	*res = &node->base;
 	return 0;
 
-error_free:
-	while (i--)
-		drm_mm_remove_node(&node->mm_nodes[i]);
+error_free_blocks:
+	spin_lock(&mgr->lock);
+	drm_buddy_free_list(mm, &vnode->blocks);
 	spin_unlock(&mgr->lock);
-	kvfree(node);
-
+error_free_res:
+	kfree(vnode);
 error_sub:
 	atomic64_sub(mem_bytes, &mgr->usage);
 	return r;
@@ -494,28 +532,28 @@ 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_node *vnode = to_amdgpu_vram_mgr_node(res);
 	struct amdgpu_vram_mgr *mgr = to_vram_mgr(man);
 	struct amdgpu_device *adev = to_amdgpu_device(mgr);
+	struct drm_buddy_mm *mm = &mgr->mm;
+	struct drm_buddy_block *block;
 	uint64_t usage = 0, 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];
-
-		drm_mm_remove_node(mm);
-		usage += mm->size << PAGE_SHIFT;
-		vis_usage += amdgpu_vram_mgr_vis_size(adev, mm);
+	list_for_each_entry(block, &vnode->blocks, link) {
+		usage += block->size << PAGE_SHIFT;
+		vis_usage += amdgpu_vram_mgr_vis_size(adev, block);
 	}
+
 	amdgpu_vram_mgr_do_reserve(man);
+
+	drm_buddy_free_list(mm, &vnode->blocks);
 	spin_unlock(&mgr->lock);
 
 	atomic64_sub(usage, &mgr->usage);
 	atomic64_sub(vis_usage, &mgr->vis_usage);
 
-	kvfree(node);
+	kfree(vnode);
 }
 
 /**
@@ -668,12 +706,6 @@ uint64_t amdgpu_vram_mgr_vis_usage(struct ttm_resource_manager *man)
 static void amdgpu_vram_mgr_debug(struct ttm_resource_manager *man,
 				  struct drm_printer *printer)
 {
-	struct amdgpu_vram_mgr *mgr = to_vram_mgr(man);
-
-	spin_lock(&mgr->lock);
-	drm_mm_print(&mgr->mm, printer);
-	spin_unlock(&mgr->lock);
-
 	drm_printf(printer, "man size:%llu pages, ram usage:%lluMB, vis usage:%lluMB\n",
 		   man->size, amdgpu_vram_mgr_usage(man) >> 20,
 		   amdgpu_vram_mgr_vis_usage(man) >> 20);
@@ -701,7 +733,7 @@ int amdgpu_vram_mgr_init(struct amdgpu_device *adev)
 
 	man->func = &amdgpu_vram_mgr_func;
 
-	drm_mm_init(&mgr->mm, 0, man->size);
+	drm_buddy_init(&mgr->mm, man->size << PAGE_SHIFT, PAGE_SIZE);
 	spin_lock_init(&mgr->lock);
 	INIT_LIST_HEAD(&mgr->reservations_pending);
 	INIT_LIST_HEAD(&mgr->reserved_pages);
@@ -737,10 +769,10 @@ void amdgpu_vram_mgr_fini(struct amdgpu_device *adev)
 		kfree(rsv);
 
 	list_for_each_entry_safe(rsv, temp, &mgr->reserved_pages, node) {
-		drm_mm_remove_node(&rsv->mm_node);
+		drm_buddy_free(&mgr->mm, &rsv->mm_node);
 		kfree(rsv);
 	}
-	drm_mm_takedown(&mgr->mm);
+	drm_buddy_fini(&mgr->mm);
 	spin_unlock(&mgr->lock);
 
 	ttm_resource_manager_cleanup(man);
-- 
2.25.1



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