On Mon, Sep 20, 2021 at 3:21 PM Arunpravin
<Arunpravin.PaneerSelvam@xxxxxxx> wrote:
>
> Replace drm_mm with drm buddy manager for
> VRAM memory management
Would be good to document why we are doing this and what advantages it
brings over the old drm_mm code.
Alex
>
> Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam@xxxxxxx>
> ---
> .../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
>
