Re: [PATCH 1/2] Enable buddy memory manager support

On Mon, Sep 20, 2021 at 3:21 PM Arunpravin Arunpravin.PaneerSelvam@amd.com wrote:

Please prefix the patch subject with drm. E.g., drm: Enable buddy memory manager support

Same for the second patch, but make it drm/amdgpu instead.

Alex

Port Intel buddy system manager to drm root folder Add CPU mappable/non-mappable region support to the drm buddy manager

Signed-off-by: Arunpravin Arunpravin.PaneerSelvam@amd.com

drivers/gpu/drm/Makefile | 2 +- drivers/gpu/drm/drm_buddy.c | 465 ++++++++++++++++++++++++++++++++++++ include/drm/drm_buddy.h | 154 ++++++++++++ 3 files changed, 620 insertions(+), 1 deletion(-) create mode 100644 drivers/gpu/drm/drm_buddy.c create mode 100644 include/drm/drm_buddy.h

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index a118692a6df7..fe1a2fc09675 100644 --- a/drivers/gpu/drm/Makefile +++ b/drivers/gpu/drm/Makefile @@ -18,7 +18,7 @@ drm-y := drm_aperture.o drm_auth.o drm_cache.o \ drm_dumb_buffers.o drm_mode_config.o drm_vblank.o \ drm_syncobj.o drm_lease.o drm_writeback.o drm_client.o \ drm_client_modeset.o drm_atomic_uapi.o drm_hdcp.o \

•           drm_managed.o drm_vblank_work.o
  

•           drm_managed.o drm_vblank_work.o drm_buddy.o
  
  

drm-$(CONFIG_DRM_LEGACY) += drm_agpsupport.o drm_bufs.o drm_context.o drm_dma.o \ drm_legacy_misc.o drm_lock.o drm_memory.o drm_scatter.o \ diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c new file mode 100644 index 000000000000..f07919a004b6 --- /dev/null +++ b/drivers/gpu/drm/drm_buddy.c @@ -0,0 +1,465 @@ +// SPDX-License-Identifier: MIT +/*

• • Copyright � 2021 Intel Corporation
• */

+#include <linux/kmemleak.h> +#include <drm/drm_buddy.h>

+static struct drm_buddy_block *drm_block_alloc(struct drm_buddy_mm *mm,

•                   struct drm_buddy_block *parent, unsigned int order,
  

•                   u64 offset)
  

+{

•   struct drm_buddy_block *block;
  

•   BUG_ON(order > DRM_BUDDY_MAX_ORDER);
  

•   block = kmem_cache_zalloc(mm->slab_blocks, GFP_KERNEL);
  

•   if (!block)
  

•           return NULL;
  

•   block->header = offset;
  

•   block->header |= order;
  

•   block->parent = parent;
  

•   block->start = offset >> PAGE_SHIFT;
  

•   block->size = (mm->chunk_size << order) >> PAGE_SHIFT;
  

•   BUG_ON(block->header & DRM_BUDDY_HEADER_UNUSED);
  

•   return block;
  

+}

+static void drm_block_free(struct drm_buddy_mm *mm, struct drm_buddy_block *block) +{

•   kmem_cache_free(mm->slab_blocks, block);
  

+}

+static void add_ordered(struct drm_buddy_mm *mm, struct drm_buddy_block *block) +{

•   struct drm_buddy_block *node;
  

•   if (list_empty(&mm->free_list[drm_buddy_block_order(block)])) {
  

•           list_add(&block->link,
  

•                           &mm->free_list[drm_buddy_block_order(block)]);
  

•           return;
  

•   }
  

•   list_for_each_entry(node, &mm->free_list[drm_buddy_block_order(block)], link)
  

•           if (block->start > node->start)
  

•                   break;
  

•   __list_add(&block->link, node->link.prev, &node->link);
  

+}

+static void mark_allocated(struct drm_buddy_block *block) +{

•   block->header &= ~DRM_BUDDY_HEADER_STATE;
  

•   block->header |= DRM_BUDDY_ALLOCATED;
  

•   list_del(&block->link);
  

+}

+static void mark_free(struct drm_buddy_mm *mm,

•                 struct drm_buddy_block *block)
  

+{

•   block->header &= ~DRM_BUDDY_HEADER_STATE;
  

•   block->header |= DRM_BUDDY_FREE;
  

•   add_ordered(mm, block);
  

+}

+static void mark_split(struct drm_buddy_block *block) +{

•   block->header &= ~DRM_BUDDY_HEADER_STATE;
  

•   block->header |= DRM_BUDDY_SPLIT;
  

•   list_del(&block->link);
  

+}

+int drm_buddy_init(struct drm_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);
  

•   BUG_ON(mm->max_order > DRM_BUDDY_MAX_ORDER);
  

•   mm->slab_blocks = KMEM_CACHE(drm_buddy_block, SLAB_HWCACHE_ALIGN);
  

•   if (!mm->slab_blocks)
  

•           return -ENOMEM;
  

•   mm->free_list = kmalloc_array(mm->max_order + 1,
  

•                                 sizeof(struct list_head),
  

•                                 GFP_KERNEL);
  

•   if (!mm->free_list)
  

•           goto out_destroy_slab;
  

•   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 drm_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 drm_buddy_block *root;
  

•           unsigned int order;
  

•           u64 root_size;
  

•           root_size = rounddown_pow_of_two(size);
  

•           order = ilog2(root_size) - ilog2(chunk_size);
  

•           root = drm_block_alloc(mm, NULL, order, offset);
  

•           if (!root)
  

•                   goto out_free_roots;
  

•           mark_free(mm, root);
  

•           BUG_ON(i > mm->max_order);
  

•           BUG_ON(drm_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--)
  

•           drm_block_free(mm, mm->roots[i]);
  

•   kfree(mm->roots);
  

+out_free_list:

•   kfree(mm->free_list);
  

+out_destroy_slab:

•   kmem_cache_destroy(mm->slab_blocks);
  

•   return -ENOMEM;
  

+} +EXPORT_SYMBOL(drm_buddy_init);

+void drm_buddy_fini(struct drm_buddy_mm *mm) +{

•   int i;
  

•   for (i = 0; i < mm->n_roots; ++i) {
  

•           WARN_ON(!drm_buddy_block_is_free(mm->roots[i]));
  

•           drm_block_free(mm, mm->roots[i]);
  

•   }
  

•   kfree(mm->roots);
  

•   kfree(mm->free_list);
  

•   kmem_cache_destroy(mm->slab_blocks);
  

+} +EXPORT_SYMBOL(drm_buddy_fini);

+static int split_block(struct drm_buddy_mm *mm,

•                  struct drm_buddy_block *block)
  

+{

•   unsigned int block_order = drm_buddy_block_order(block) - 1;
  

•   u64 offset = drm_buddy_block_offset(block);
  

•   BUG_ON(!drm_buddy_block_is_free(block));
  

•   BUG_ON(!drm_buddy_block_order(block));
  

•   block->left = drm_block_alloc(mm, block, block_order, offset);
  

•   if (!block->left)
  

•           return -ENOMEM;
  

•   block->right = drm_block_alloc(mm, block, block_order,
  

•                                   offset + (mm->chunk_size << block_order));
  

•   if (!block->right) {
  

•           drm_block_free(mm, block->left);
  

•           return -ENOMEM;
  

•   }
  

•   mark_free(mm, block->left);
  

•   mark_free(mm, block->right);
  

•   mark_split(block);
  

•   return 0;
  

+}

+static struct drm_buddy_block * +get_buddy(struct drm_buddy_block *block) +{

•   struct drm_buddy_block *parent;
  

•   parent = block->parent;
  

•   if (!parent)
  

•           return NULL;
  

•   if (parent->left == block)
  

•           return parent->right;
  

•   return parent->left;
  

+}

+static void __drm_buddy_free(struct drm_buddy_mm *mm,

•                         struct drm_buddy_block *block)
  

+{

•   struct drm_buddy_block *parent;
  

•   while ((parent = block->parent)) {
  

•           struct drm_buddy_block *buddy;
  

•           buddy = get_buddy(block);
  

•           if (!drm_buddy_block_is_free(buddy))
  

•                   break;
  

•           list_del(&buddy->link);
  

•           drm_block_free(mm, block);
  

•           drm_block_free(mm, buddy);
  

•           block = parent;
  

•   }
  

•   mark_free(mm, block);
  

+}

+void drm_buddy_free(struct drm_buddy_mm *mm,

•                struct drm_buddy_block *block)
  

+{

•   BUG_ON(!drm_buddy_block_is_allocated(block));
  

•   __drm_buddy_free(mm, block);
  

+} +EXPORT_SYMBOL(drm_buddy_free);

+void drm_buddy_free_list(struct drm_buddy_mm *mm, struct list_head *objects) +{

•   struct drm_buddy_block *block, *on;
  

•   list_for_each_entry_safe(block, on, objects, link) {
  

•           drm_buddy_free(mm, block);
  

•           cond_resched();
  

•   }
  

•   INIT_LIST_HEAD(objects);
  

+} +EXPORT_SYMBOL(drm_buddy_free_list);

+/*

• • 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 drm_buddy_block * +drm_buddy_alloc(struct drm_buddy_mm *mm, unsigned int order,

•           bool bar_enabled, unsigned int limit,
  

•           enum drm_buddy_alloc_mode mode)
  

+{

•   struct drm_buddy_block *block = NULL;
  

•   unsigned int pages;
  

•   unsigned int i;
  

•   int err;
  

•   pages = (mm->chunk_size << order) >> PAGE_SHIFT;
  

•   for (i = order; i <= mm->max_order; ++i) {
  

•           if (mode == DRM_BUDDY_TOP_DOWN) {
  

•                   if (!list_empty(&mm->free_list[i])) {
  

•                           block = list_first_entry(&mm->free_list[i],
  

•                                           struct drm_buddy_block, link);
  

•                           if (bar_enabled) {
  

•                                   if (!(block->start > limit))
  

•                                           continue;
  

•                           }
  

•                           break;
  

•                   }
  

•           } else if (mode == DRM_BUDDY_BOTTOM_UP) {
  

•                   if (!list_empty(&mm->free_list[i])) {
  

•                           block = list_last_entry(&mm->free_list[i],
  

•                                           struct drm_buddy_block, link);
  

•                           if (bar_enabled) {
  

•                                   if (!(block->start < limit &&
  

•                                                   (block->start + pages) < limit))
  

•                                           continue;
  

•                           }
  

•                           break;
  

•                   }
  

•           }
  

•   }
  

•   if (!block)
  

•           return ERR_PTR(-ENOSPC);
  

•   BUG_ON(!drm_buddy_block_is_free(block));
  

•   while (i != order) {
  

•           err = split_block(mm, block);
  

•           if (unlikely(err))
  

•                   goto out_free;
  

•           /* Go low */
  

•           if (mode == DRM_BUDDY_TOP_DOWN)
  

•                   block = block->right;
  

•           else
  

•                   block = block->left;
  

•           i--;
  

•   }
  

•   if (mode == DRM_BUDDY_TOP_DOWN && bar_enabled) {
  

•           if (!(block->start > limit))
  

•                   return ERR_PTR(-ENOSPC);
  

•   } else if (mode == DRM_BUDDY_BOTTOM_UP && bar_enabled) {
  

•           if (!(block->start < limit &&
  

•                           (block->start + pages) < limit))
  

•                   return ERR_PTR(-ENOSPC);
  

•   }
  

•   mark_allocated(block);
  

•   kmemleak_update_trace(block);
  

•   return block;
  

+out_free:

•   if (i != order)
  

•           __drm_buddy_free(mm, block);
  

•   return ERR_PTR(err);
  

+} +EXPORT_SYMBOL(drm_buddy_alloc);

+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 drm_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 drm_buddy_alloc_range(struct drm_buddy_mm *mm,

•                   struct list_head *blocks,
  

•                   u64 start, u64 size)
  

+{

•   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;
  

•   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);
  

•           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)) {
  

•                   err = -ENOSPC;
  

•                   goto err_free;
  

•           }
  

•           if (contains(start, end, block_start, block_end)) {
  

•                   if (!drm_buddy_block_is_free(block)) {
  

•                           err = -ENOSPC;
  

•                           goto err_free;
  

•                   }
  

•                   mark_allocated(block);
  

•                   list_add_tail(&block->link, &allocated);
  

•                   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);
  

•   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 &&
  

•       (drm_buddy_block_is_free(block) &&
  

•        drm_buddy_block_is_free(buddy)))
  

•           __drm_buddy_free(mm, block);
  

+err_free:

•   drm_buddy_free_list(mm, &allocated);
  

•   return err;
  

+} +EXPORT_SYMBOL(drm_buddy_alloc_range); diff --git a/include/drm/drm_buddy.h b/include/drm/drm_buddy.h new file mode 100644 index 000000000000..50e4d819a3dd --- /dev/null +++ b/include/drm/drm_buddy.h @@ -0,0 +1,154 @@ +/* SPDX-License-Identifier: MIT */ +/*

• • Copyright � 2021 Intel Corporation
• */

+#ifndef __DRM_BUDDY_H__ +#define __DRM_BUDDY_H__

+#include <linux/bitops.h> +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/sched.h>

+#define range_overflows(start, size, max) ({ \

•   typeof(start) start__ = (start); \
  

•   typeof(size) size__ = (size); \
  

•   typeof(max) max__ = (max); \
  

•   (void)(&start__ == &size__); \
  

•   (void)(&start__ == &max__); \
  

•   start__ >= max__ || size__ > max__ - start__; \
  

+})

+enum drm_buddy_alloc_mode {

•    DRM_BUDDY_TOP_DOWN = 0,
  

•    DRM_BUDDY_BOTTOM_UP,
  

•    DRM_BUDDY_ALLOC_RANGE
  

+};

+struct drm_buddy_block { +#define DRM_BUDDY_HEADER_OFFSET GENMASK_ULL(63, 12) +#define DRM_BUDDY_HEADER_STATE GENMASK_ULL(11, 10) +#define DRM_BUDDY_ALLOCATED (1 << 10) +#define DRM_BUDDY_FREE (2 << 10) +#define DRM_BUDDY_SPLIT (3 << 10) +/* Free to be used, if needed in the future */ +#define DRM_BUDDY_HEADER_UNUSED GENMASK_ULL(9, 6) +#define DRM_BUDDY_HEADER_ORDER GENMASK_ULL(5, 0)

•   u64 header;
  

•   /* Store start and size fields in pages */
  

•   u64 start;
  

•   u64 size;
  

•   struct drm_buddy_block *left;
  

•   struct drm_buddy_block *right;
  

•   struct drm_buddy_block *parent;
  

•   void *private; /* owned by creator */
  

•   /*
  

•    * While the block is allocated by the user through drm_buddy_alloc*,
  

•    * the user has ownership of the link, for example to maintain within
  

•    * a list, if so desired. As soon as the block is freed with
  

•    * drm_buddy_free* ownership is given back to the mm.
  

•    */
  

•   struct list_head link;
  

•   struct list_head tmp_link;
  

+};

+/* Order-zero must be at least PAGE_SIZE */ +#define DRM_BUDDY_MAX_ORDER (63 - PAGE_SHIFT)

+/*

• • Binary Buddy System.
• • Locking should be handled by the user, a simple mutex around
• • drm_buddy_alloc* and drm_buddy_free* should suffice.
• */

+struct drm_buddy_mm {

•   struct kmem_cache *slab_blocks;
  

•   /* Maintain a free list for each order. */
  

•   struct list_head *free_list;
  

•   /*
  

•    * Maintain explicit binary tree(s) to track the allocation of the
  

•    * address space. This gives us a simple way of finding a buddy block
  

•    * and performing the potentially recursive merge step when freeing a
  

•    * block.  Nodes are either allocated or free, in which case they will
  

•    * also exist on the respective free list.
  

•    */
  

•   struct drm_buddy_block **roots;
  

•   /*
  

•    * Anything from here is public, and remains static for the lifetime of
  

•    * the mm. Everything above is considered do-not-touch.
  

•    */
  

•   unsigned int n_roots;
  

•   unsigned int max_order;
  

•   /* Must be at least PAGE_SIZE */
  

•   u64 chunk_size;
  

•   u64 size;
  

+};

+static inline u64 +drm_buddy_block_offset(struct drm_buddy_block *block) +{

•   return block->header & DRM_BUDDY_HEADER_OFFSET;
  

+}

+static inline unsigned int +drm_buddy_block_order(struct drm_buddy_block *block) +{

•   return block->header & DRM_BUDDY_HEADER_ORDER;
  

+}

+static inline unsigned int +drm_buddy_block_state(struct drm_buddy_block *block) +{

•   return block->header & DRM_BUDDY_HEADER_STATE;
  

+}

+static inline bool +drm_buddy_block_is_allocated(struct drm_buddy_block *block) +{

•   return drm_buddy_block_state(block) == DRM_BUDDY_ALLOCATED;
  

+}

+static inline bool +drm_buddy_block_is_free(struct drm_buddy_block *block) +{

•   return drm_buddy_block_state(block) == DRM_BUDDY_FREE;
  

+}

+static inline bool +drm_buddy_block_is_split(struct drm_buddy_block *block) +{

•   return drm_buddy_block_state(block) == DRM_BUDDY_SPLIT;
  

+}

+static inline u64 +drm_buddy_block_size(struct drm_buddy_mm *mm,

•                 struct drm_buddy_block *block)
  

+{

•   return mm->chunk_size << drm_buddy_block_order(block);
  

+}

+int drm_buddy_init(struct drm_buddy_mm *mm, u64 size, u64 chunk_size);

+void drm_buddy_fini(struct drm_buddy_mm *mm);

+struct drm_buddy_block * +drm_buddy_alloc(struct drm_buddy_mm *mm, unsigned int order,

•           bool bar_limit_enabled, unsigned int limit,
  

•           enum drm_buddy_alloc_mode mode);
  

+int drm_buddy_alloc_range(struct drm_buddy_mm *mm,

•                      struct list_head *blocks,
  

•                      u64 start, u64 size);
  

+void drm_buddy_free(struct drm_buddy_mm *mm, struct drm_buddy_block *block);

+void drm_buddy_free_list(struct drm_buddy_mm *mm, struct list_head *objects);

+#endif

2.25.1