Re: [PATCH v3 1/6] drm: move the buddy allocator from i915 into common drm

Hi Christian, I will make this a separate module.

Thanks, Arun

On 17/11/21 1:33 pm, Christian König wrote:

I've looked a bit more into this and I think we should just follow Thomas Zimmermann's idea to make this a separate module.

Otherwise we just have the code around all the time even if it is unused and implementing this should be trivial.

See how DRM_GEM_CMA_HELPER or DRM_VRAM_HELPER are done in drivers/gpu/drm/Kconfig and then have the desired effect in drivers/gpu/drm/Makefile

Should be something like ~15 lines of additional configuration which saves a bit of memory on embedded systems which just need a fbdev replacement.

Thanks, Christian.

Am 16.11.21 um 21:18 schrieb Arunpravin:

...

Move the base i915 buddy allocator code into drm

• Move i915_buddy.h to include/drm
• Move i915_buddy.c to drm root folder
• Rename "i915" string with "drm" string wherever applicable
• Rename "I915" string with "DRM" string wherever applicable
• Fix header file dependencies
• Fix alignment issues
• add Makefile support for drm buddy
• export functions and write kerneldoc description
• Remove i915 selftest config check condition as buddy selftest will be moved to drm selftest folder

cleanup i915 buddy references in i915 driver module and replace with drm buddy

v2:

• include header file in alphabetical order (Thomas)
• merged changes listed in the body section into a single patch to keep the build intact (Christian, Jani)

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

drivers/gpu/drm/Makefile | 2 +- drivers/gpu/drm/drm_buddy.c | 521 ++++++++++++++++++ drivers/gpu/drm/drm_drv.c | 3 + drivers/gpu/drm/i915/Makefile | 1 - drivers/gpu/drm/i915/i915_buddy.c | 466 ---------------- drivers/gpu/drm/i915/i915_buddy.h | 143 ----- drivers/gpu/drm/i915/i915_module.c | 3 - drivers/gpu/drm/i915/i915_scatterlist.c | 11 +- drivers/gpu/drm/i915/i915_ttm_buddy_manager.c | 33 +- drivers/gpu/drm/i915/i915_ttm_buddy_manager.h | 4 +- include/drm/drm_buddy.h | 153 +++++ 11 files changed, 702 insertions(+), 638 deletions(-) create mode 100644 drivers/gpu/drm/drm_buddy.c delete mode 100644 drivers/gpu/drm/i915/i915_buddy.c delete mode 100644 drivers/gpu/drm/i915/i915_buddy.h create mode 100644 include/drm/drm_buddy.h

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index 0dff40bb863c..dc61e91a3154 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..39eb1d224bec --- /dev/null +++ b/drivers/gpu/drm/drm_buddy.c @@ -0,0 +1,521 @@ +// SPDX-License-Identifier: MIT +/*

• • Copyright © 2021 Intel Corporation
• */

+#include <linux/kmemleak.h> +#include <linux/sizes.h>

+#include <drm/drm_buddy.h>

+static struct kmem_cache *slab_blocks;

+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(slab_blocks, GFP_KERNEL);
• if (!block)

• return NULL;
  

• block->header = offset;
• block->header |= order;
• block->parent = parent;
• 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(slab_blocks, block);

+}

+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;
• list_add(&block->link,

•  &mm->free_list[drm_buddy_block_order(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);

+}

+/**

• • drm_buddy_init - init memory manager
• • @mm: DRM buddy manager to initialize
• • @size: size in bytes to manage
• • @chunk_size: minimum page size in bytes for our allocations
• • Initializes the memory manager and its resources.
• • Returns:
• • 0 on success, error code on failure.
• */

+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->avail = size;
• mm->chunk_size = chunk_size;
• mm->max_order = ilog2(size) - ilog2(chunk_size);
• BUG_ON(mm->max_order > DRM_BUDDY_MAX_ORDER);
• mm->free_list = kmalloc_array(mm->max_order + 1,

• 		      sizeof(struct list_head),
  

• 		      GFP_KERNEL);
  

• if (!mm->free_list)

• return -ENOMEM;
  

• 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);
• return -ENOMEM;

+} +EXPORT_SYMBOL(drm_buddy_init);

+/**

• • drm_buddy_fini - tear down the memory manager
• • @mm: DRM buddy manager to free
• • Cleanup memory manager resources and the freelist
• */

+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]);
  

• }
• WARN_ON(mm->avail != mm->size);
• kfree(mm->roots);
• kfree(mm->free_list);

+} +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));
• mm->avail += drm_buddy_block_size(mm, block);
• __drm_buddy_free(mm, block);

+}

+/**

• • drm_buddy_free_list - free blocks
• • @mm: DRM buddy manager
• • @objects: input list head to free blocks
• */

+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);

+/**

• • drm_buddy_alloc - 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(struct drm_buddy_mm *mm, unsigned int order) +{

• struct drm_buddy_block *block = NULL;
• unsigned int i;
• int err;
• for (i = order; i <= mm->max_order; ++i) {

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

• 				 struct drm_buddy_block,
  

• 				 link);
  

• if (block)
  

• 	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 */
  

• block = block->left;
  

• i--;
  

• }
• mark_allocated(block);
• mm->avail -= drm_buddy_block_size(mm, 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;

+}

+/**

• • 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() 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 *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);
  

• 	mm->avail -= drm_buddy_block_size(mm, 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);

+/**

• • drm_buddy_block_print - print block information
• • @mm: DRM buddy manager
• • @block: DRM buddy block
• • @p: DRM printer to use
• */

+void drm_buddy_block_print(struct drm_buddy_mm *mm,

• 	   struct drm_buddy_block *block,
  

• 	   struct drm_printer *p)
  

+{

• u64 start = drm_buddy_block_offset(block);
• u64 size = drm_buddy_block_size(mm, block);
• drm_printf(p, "%#018llx-%#018llx: %llu\n", start, start + size, size);

+} +EXPORT_SYMBOL(drm_buddy_block_print);

+/**

• • drm_buddy_print - print allocator state
• • @mm: DRM buddy manager
• • @p: DRM printer to use
• */

+void drm_buddy_print(struct drm_buddy_mm *mm, struct drm_printer *p) +{

• int order;
• drm_printf(p, "chunk_size: %lluKiB, total: %lluMiB, free: %lluMiB\n",

•    mm->chunk_size >> 10, mm->size >> 20, mm->avail >> 20);
  

• for (order = mm->max_order; order >= 0; order--) {

• struct drm_buddy_block *block;
  

• u64 count = 0, free;
  

• list_for_each_entry(block, &mm->free_list[order], link) {
  

• 	BUG_ON(!drm_buddy_block_is_free(block));
  

• 	count++;
  

• }
  

• drm_printf(p, "order-%d ", order);
  

• free = count * (mm->chunk_size << order);
  

• if (free < SZ_1M)
  

• 	drm_printf(p, "free: %lluKiB", free >> 10);
  

• else
  

• 	drm_printf(p, "free: %lluMiB", free >> 20);
  

• drm_printf(p, ", pages: %llu\n", count);
  

• }

+} +EXPORT_SYMBOL(drm_buddy_print);

+void drm_buddy_module_exit(void) +{

• kmem_cache_destroy(slab_blocks);

+}

+int __init drm_buddy_module_init(void) +{

• slab_blocks = KMEM_CACHE(drm_buddy_block, 0);
• if (!slab_blocks)

• return -ENOMEM;
  

• return 0;

+} diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 7a5097467ba5..5d5e46e60586 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -35,6 +35,7 @@ #include <linux/slab.h> #include <linux/srcu.h>

+#include <drm/drm_buddy.h> #include <drm/drm_cache.h> #include <drm/drm_client.h> #include <drm/drm_color_mgmt.h> @@ -1034,6 +1035,7 @@ static void drm_core_exit(void) drm_sysfs_destroy(); idr_destroy(&drm_minors_idr); drm_connector_ida_destroy();

• drm_buddy_module_exit(); }

  static int __init drm_core_init(void)

@@ -1043,6 +1045,7 @@ static int __init drm_core_init(void) drm_connector_ida_init(); idr_init(&drm_minors_idr); drm_memcpy_init_early();

• drm_buddy_module_init();

  ret = drm_sysfs_init(); if (ret < 0) {

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile index 467872cca027..fc5ca8c4ccb2 100644 --- a/drivers/gpu/drm/i915/Makefile +++ b/drivers/gpu/drm/i915/Makefile @@ -161,7 +161,6 @@ gem-y += \ i915-y += \ $(gem-y) \ i915_active.o \

•  i915_buddy.o \
  

  i915_cmd_parser.o \ i915_gem_evict.o \ i915_gem_gtt.o \

diff --git a/drivers/gpu/drm/i915/i915_buddy.c b/drivers/gpu/drm/i915/i915_buddy.c deleted file mode 100644 index 6e2ad68f8f3f..000000000000 --- a/drivers/gpu/drm/i915/i915_buddy.c +++ /dev/null @@ -1,466 +0,0 @@ -// SPDX-License-Identifier: MIT -/*

• • Copyright © 2021 Intel Corporation
• */

-#include <linux/kmemleak.h> -#include <linux/sizes.h>

-#include "i915_buddy.h"

-#include "i915_gem.h" -#include "i915_utils.h"

-static struct kmem_cache *slab_blocks;

-static struct i915_buddy_block *i915_block_alloc(struct i915_buddy_mm *mm,

• 				 struct i915_buddy_block *parent,
  

• 				 unsigned int order,
  

• 				 u64 offset)
  

-{

• struct i915_buddy_block *block;
• GEM_BUG_ON(order > I915_BUDDY_MAX_ORDER);
• block = kmem_cache_zalloc(slab_blocks, GFP_KERNEL);
• if (!block)

• return NULL;
  

• block->header = offset;
• block->header |= order;
• block->parent = parent;
• GEM_BUG_ON(block->header & I915_BUDDY_HEADER_UNUSED);
• return block;

-}

-static void i915_block_free(struct i915_buddy_mm *mm,

• 	    struct i915_buddy_block *block)
  

-{

• kmem_cache_free(slab_blocks, block);

-}

-static void mark_allocated(struct i915_buddy_block *block) -{

• block->header &= ~I915_BUDDY_HEADER_STATE;
• block->header |= I915_BUDDY_ALLOCATED;
• list_del(&block->link);

-}

-static void mark_free(struct i915_buddy_mm *mm,

•       struct i915_buddy_block *block)
  

-{

• block->header &= ~I915_BUDDY_HEADER_STATE;
• block->header |= I915_BUDDY_FREE;
• list_add(&block->link,

•  &mm->free_list[i915_buddy_block_order(block)]);
  

-}

-static void mark_split(struct i915_buddy_block *block) -{

• block->header &= ~I915_BUDDY_HEADER_STATE;
• block->header |= I915_BUDDY_SPLIT;
• list_del(&block->link);

-}

-int i915_buddy_init(struct i915_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->avail = size;
• mm->chunk_size = chunk_size;
• mm->max_order = ilog2(size) - ilog2(chunk_size);
• GEM_BUG_ON(mm->max_order > I915_BUDDY_MAX_ORDER);
• mm->free_list = kmalloc_array(mm->max_order + 1,

• 		      sizeof(struct list_head),
  

• 		      GFP_KERNEL);
  

• if (!mm->free_list)

• return -ENOMEM;
  

• 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 i915_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 i915_buddy_block *root;
  

• unsigned int order;
  

• u64 root_size;
  

• root_size = rounddown_pow_of_two(size);
  

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

• root = i915_block_alloc(mm, NULL, order, offset);
  

• if (!root)
  

• 	goto out_free_roots;
  

• mark_free(mm, root);
  

• GEM_BUG_ON(i > mm->max_order);
  

• GEM_BUG_ON(i915_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--)

• i915_block_free(mm, mm->roots[i]);
  

• kfree(mm->roots);

-out_free_list:

• kfree(mm->free_list);
• return -ENOMEM;

-}

-void i915_buddy_fini(struct i915_buddy_mm *mm) -{

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

• GEM_WARN_ON(!i915_buddy_block_is_free(mm->roots[i]));
  

• i915_block_free(mm, mm->roots[i]);
  

• }
• GEM_WARN_ON(mm->avail != mm->size);
• kfree(mm->roots);
• kfree(mm->free_list);

-}

-static int split_block(struct i915_buddy_mm *mm,

•        struct i915_buddy_block *block)
  

-{

• unsigned int block_order = i915_buddy_block_order(block) - 1;
• u64 offset = i915_buddy_block_offset(block);
• GEM_BUG_ON(!i915_buddy_block_is_free(block));
• GEM_BUG_ON(!i915_buddy_block_order(block));
• block->left = i915_block_alloc(mm, block, block_order, offset);
• if (!block->left)

• return -ENOMEM;
  

• block->right = i915_block_alloc(mm, block, block_order,

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

• if (!block->right) {

• i915_block_free(mm, block->left);
  

• return -ENOMEM;
  

• }
• mark_free(mm, block->left);
• mark_free(mm, block->right);
• mark_split(block);
• return 0;

-}

-static struct i915_buddy_block * -get_buddy(struct i915_buddy_block *block) -{

• struct i915_buddy_block *parent;
• parent = block->parent;
• if (!parent)

• return NULL;
  

• if (parent->left == block)

• return parent->right;
  

• return parent->left;

-}

-static void __i915_buddy_free(struct i915_buddy_mm *mm,

• 	      struct i915_buddy_block *block)
  

-{

• struct i915_buddy_block *parent;
• while ((parent = block->parent)) {

• struct i915_buddy_block *buddy;
  

• buddy = get_buddy(block);
  

• if (!i915_buddy_block_is_free(buddy))
  

• 	break;
  

• list_del(&buddy->link);
  

• i915_block_free(mm, block);
  

• i915_block_free(mm, buddy);
  

• block = parent;
  

• }
• mark_free(mm, block);

-}

-void i915_buddy_free(struct i915_buddy_mm *mm,

•      struct i915_buddy_block *block)
  

-{

• GEM_BUG_ON(!i915_buddy_block_is_allocated(block));
• mm->avail += i915_buddy_block_size(mm, block);
• __i915_buddy_free(mm, block);

-}

-void i915_buddy_free_list(struct i915_buddy_mm *mm, struct list_head *objects) -{

• struct i915_buddy_block *block, *on;
• list_for_each_entry_safe(block, on, objects, link) {

• i915_buddy_free(mm, block);
  

• cond_resched();
  

• }
• INIT_LIST_HEAD(objects);

-}

-/*

• • 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 i915_buddy_block * -i915_buddy_alloc(struct i915_buddy_mm *mm, unsigned int order) -{

• struct i915_buddy_block *block = NULL;
• unsigned int i;
• int err;
• for (i = order; i <= mm->max_order; ++i) {

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

• 				 struct i915_buddy_block,
  

• 				 link);
  

• if (block)
  

• 	break;
  

• }
• if (!block)

• return ERR_PTR(-ENOSPC);
  

• GEM_BUG_ON(!i915_buddy_block_is_free(block));
• while (i != order) {

• err = split_block(mm, block);
  

• if (unlikely(err))
  

• 	goto out_free;
  

• /* Go low */
  

• block = block->left;
  

• i--;
  

• }
• mark_allocated(block);
• mm->avail -= i915_buddy_block_size(mm, block);
• kmemleak_update_trace(block);
• return block;

-out_free:

• if (i != order)

• __i915_buddy_free(mm, block);
  

• return ERR_PTR(err);

-}

-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 i915_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 i915_buddy_alloc_range(struct i915_buddy_mm *mm,

• 	   struct list_head *blocks,
  

• 	   u64 start, u64 size)
  

-{

• struct i915_buddy_block *block;
• struct i915_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 i915_buddy_block,
  

• 				 tmp_link);
  

• if (!block)
  

• 	break;
  

• list_del(&block->tmp_link);
  

• block_start = i915_buddy_block_offset(block);
  

• block_end = block_start + i915_buddy_block_size(mm, block) - 1;
  

• if (!overlaps(start, end, block_start, block_end))
  

• 	continue;
  

• if (i915_buddy_block_is_allocated(block)) {
  

• 	err = -ENOSPC;
  

• 	goto err_free;
  

• }
  

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

• 	if (!i915_buddy_block_is_free(block)) {
  

• 		err = -ENOSPC;
  

• 		goto err_free;
  

• 	}
  

• 	mark_allocated(block);
  

• 	mm->avail -= i915_buddy_block_size(mm, block);
  

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

• 	continue;
  

• }
  

• if (!i915_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 &&

•    (i915_buddy_block_is_free(block) &&
  

•     i915_buddy_block_is_free(buddy)))
  

• __i915_buddy_free(mm, block);
  

-err_free:

• i915_buddy_free_list(mm, &allocated);
• return err;

-}

-void i915_buddy_block_print(struct i915_buddy_mm *mm,

• 	    struct i915_buddy_block *block,
  

• 	    struct drm_printer *p)
  

-{

• u64 start = i915_buddy_block_offset(block);
• u64 size = i915_buddy_block_size(mm, block);
• drm_printf(p, "%#018llx-%#018llx: %llu\n", start, start + size, size);

-}

-void i915_buddy_print(struct i915_buddy_mm *mm, struct drm_printer *p) -{

• int order;
• drm_printf(p, "chunk_size: %lluKiB, total: %lluMiB, free: %lluMiB\n",

•    mm->chunk_size >> 10, mm->size >> 20, mm->avail >> 20);
  

• for (order = mm->max_order; order >= 0; order--) {

• struct i915_buddy_block *block;
  

• u64 count = 0, free;
  

• list_for_each_entry(block, &mm->free_list[order], link) {
  

• 	GEM_BUG_ON(!i915_buddy_block_is_free(block));
  

• 	count++;
  

• }
  

• drm_printf(p, "order-%d ", order);
  

• free = count * (mm->chunk_size << order);
  

• if (free < SZ_1M)
  

• 	drm_printf(p, "free: %lluKiB", free >> 10);
  

• else
  

• 	drm_printf(p, "free: %lluMiB", free >> 20);
  

• drm_printf(p, ", pages: %llu\n", count);
  

• }

-}

-#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST) -#include "selftests/i915_buddy.c" -#endif

-void i915_buddy_module_exit(void) -{

• kmem_cache_destroy(slab_blocks);

-}

-int __init i915_buddy_module_init(void) -{

• slab_blocks = KMEM_CACHE(i915_buddy_block, 0);
• if (!slab_blocks)

• return -ENOMEM;
  

• return 0;

-} diff --git a/drivers/gpu/drm/i915/i915_buddy.h b/drivers/gpu/drm/i915/i915_buddy.h deleted file mode 100644 index 7077742112ac..000000000000 --- a/drivers/gpu/drm/i915/i915_buddy.h +++ /dev/null @@ -1,143 +0,0 @@ -/* SPDX-License-Identifier: MIT */ -/*

• • Copyright © 2021 Intel Corporation
• */

-#ifndef __I915_BUDDY_H__ -#define __I915_BUDDY_H__

-#include <linux/bitops.h> -#include <linux/list.h> -#include <linux/slab.h>

-#include <drm/drm_print.h>

-struct i915_buddy_block { -#define I915_BUDDY_HEADER_OFFSET GENMASK_ULL(63, 12) -#define I915_BUDDY_HEADER_STATE GENMASK_ULL(11, 10) -#define I915_BUDDY_ALLOCATED (1 << 10) -#define I915_BUDDY_FREE (2 << 10) -#define I915_BUDDY_SPLIT (3 << 10) -/* Free to be used, if needed in the future */ -#define I915_BUDDY_HEADER_UNUSED GENMASK_ULL(9, 6) -#define I915_BUDDY_HEADER_ORDER GENMASK_ULL(5, 0)

• u64 header;
• struct i915_buddy_block *left;
• struct i915_buddy_block *right;
• struct i915_buddy_block *parent;
• void *private; /* owned by creator */
• /*

• * While the block is allocated by the user through i915_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
  

• * i915_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 I915_BUDDY_MAX_ORDER (63 - PAGE_SHIFT)

-/*

• • Binary Buddy System.
• • Locking should be handled by the user, a simple mutex around
• • i915_buddy_alloc* and i915_buddy_free* should suffice.
• */

-struct i915_buddy_mm {

• /* 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 i915_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;
• u64 avail;

-};

-static inline u64 -i915_buddy_block_offset(struct i915_buddy_block *block) -{

• return block->header & I915_BUDDY_HEADER_OFFSET;

-}

-static inline unsigned int -i915_buddy_block_order(struct i915_buddy_block *block) -{

• return block->header & I915_BUDDY_HEADER_ORDER;

-}

-static inline unsigned int -i915_buddy_block_state(struct i915_buddy_block *block) -{

• return block->header & I915_BUDDY_HEADER_STATE;

-}

-static inline bool -i915_buddy_block_is_allocated(struct i915_buddy_block *block) -{

• return i915_buddy_block_state(block) == I915_BUDDY_ALLOCATED;

-}

-static inline bool -i915_buddy_block_is_free(struct i915_buddy_block *block) -{

• return i915_buddy_block_state(block) == I915_BUDDY_FREE;

-}

-static inline bool -i915_buddy_block_is_split(struct i915_buddy_block *block) -{

• return i915_buddy_block_state(block) == I915_BUDDY_SPLIT;

-}

-static inline u64 -i915_buddy_block_size(struct i915_buddy_mm *mm,

•       struct i915_buddy_block *block)
  

-{

• return mm->chunk_size << i915_buddy_block_order(block);

-}

-int i915_buddy_init(struct i915_buddy_mm *mm, u64 size, u64 chunk_size);

-void i915_buddy_fini(struct i915_buddy_mm *mm);

-struct i915_buddy_block * -i915_buddy_alloc(struct i915_buddy_mm *mm, unsigned int order);

-int i915_buddy_alloc_range(struct i915_buddy_mm *mm,

• 	   struct list_head *blocks,
  

• 	   u64 start, u64 size);
  

-void i915_buddy_free(struct i915_buddy_mm *mm, struct i915_buddy_block *block);

-void i915_buddy_free_list(struct i915_buddy_mm *mm, struct list_head *objects);

-void i915_buddy_print(struct i915_buddy_mm *mm, struct drm_printer *p); -void i915_buddy_block_print(struct i915_buddy_mm *mm,

• 	    struct i915_buddy_block *block,
  

• 	    struct drm_printer *p);
  

-void i915_buddy_module_exit(void); -int i915_buddy_module_init(void);

-#endif diff --git a/drivers/gpu/drm/i915/i915_module.c b/drivers/gpu/drm/i915/i915_module.c index c7507266aa83..355681dbd7a8 100644 --- a/drivers/gpu/drm/i915/i915_module.c +++ b/drivers/gpu/drm/i915/i915_module.c @@ -9,7 +9,6 @@ #include "gem/i915_gem_context.h" #include "gem/i915_gem_object.h" #include "i915_active.h" -#include "i915_buddy.h" #include "i915_params.h" #include "i915_pci.h" #include "i915_perf.h" @@ -50,8 +49,6 @@ static const struct { { .init = i915_check_nomodeset }, { .init = i915_active_module_init, .exit = i915_active_module_exit },

• { .init = i915_buddy_module_init,

•  .exit = i915_buddy_module_exit },
  

  { .init = i915_context_module_init, .exit = i915_context_module_exit }, { .init = i915_gem_context_module_init,

diff --git a/drivers/gpu/drm/i915/i915_scatterlist.c b/drivers/gpu/drm/i915/i915_scatterlist.c index 4a6712dca838..84d622aa32d2 100644 --- a/drivers/gpu/drm/i915/i915_scatterlist.c +++ b/drivers/gpu/drm/i915/i915_scatterlist.c @@ -5,10 +5,9 @@ */

#include "i915_scatterlist.h"

-#include "i915_buddy.h" #include "i915_ttm_buddy_manager.h"

+#include <drm/drm_buddy.h> #include <drm/drm_mm.h>

#include <linux/slab.h> @@ -126,9 +125,9 @@ struct sg_table *i915_sg_from_buddy_resource(struct ttm_resource *res, struct i915_ttm_buddy_resource *bman_res = to_ttm_buddy_resource(res); const u64 size = res->num_pages << PAGE_SHIFT; const u64 max_segment = rounddown(UINT_MAX, PAGE_SIZE);

• struct i915_buddy_mm *mm = bman_res->mm;

• struct drm_buddy_mm *mm = bman_res->mm; struct list_head *blocks = &bman_res->blocks;

• struct i915_buddy_block *block;

• struct drm_buddy_block *block; struct scatterlist *sg; struct sg_table *st; resource_size_t prev_end;

@@ -151,8 +150,8 @@ struct sg_table *i915_sg_from_buddy_resource(struct ttm_resource *res, list_for_each_entry(block, blocks, link) { u64 block_size, offset;

• block_size = min_t(u64, size, i915_buddy_block_size(mm, block));
  

• offset = i915_buddy_block_offset(block);
  

• block_size = min_t(u64, size, drm_buddy_block_size(mm, block));
  

• offset = drm_buddy_block_offset(block);
  
  

  while (block_size) { u64 len;

diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c index d59fbb019032..c4b70cb8c248 100644 --- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c +++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c @@ -8,14 +8,15 @@ #include <drm/ttm/ttm_bo_driver.h> #include <drm/ttm/ttm_placement.h>

+#include <drm/drm_buddy.h>

• #include "i915_ttm_buddy_manager.h"

-#include "i915_buddy.h" #include "i915_gem.h"

struct i915_ttm_buddy_manager { struct ttm_resource_manager manager;

• struct i915_buddy_mm mm;

• struct drm_buddy_mm mm; struct list_head reserved; struct mutex lock; u64 default_page_size;

@@ -34,7 +35,7 @@ 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 i915_buddy_mm *mm = &bman->mm;

• struct drm_buddy_mm *mm = &bman->mm; unsigned long n_pages; unsigned int min_order; u64 min_page_size;

@@ -73,7 +74,7 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man, n_pages = size >> ilog2(mm->chunk_size);

do {

• struct i915_buddy_block *block;
  

• struct drm_buddy_block *block;
  

  unsigned int order;

  order = fls(n_pages) - 1;

@@ -82,7 +83,7 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,

do {
	mutex_lock(&bman->lock);

• 	block = i915_buddy_alloc(mm, order);
  

• 	block = drm_buddy_alloc(mm, order);
  mutex_unlock(&bman->lock);
  if (!IS_ERR(block))
  	break;
  

@@ -106,7 +107,7 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,

err_free_blocks: mutex_lock(&bman->lock);

• i915_buddy_free_list(mm, &bman_res->blocks);

• drm_buddy_free_list(mm, &bman_res->blocks); mutex_unlock(&bman->lock); err_free_res: kfree(bman_res);

@@ -120,7 +121,7 @@ static void i915_ttm_buddy_man_free(struct ttm_resource_manager *man, struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);

mutex_lock(&bman->lock);

• i915_buddy_free_list(&bman->mm, &bman_res->blocks);

• drm_buddy_free_list(&bman->mm, &bman_res->blocks); mutex_unlock(&bman->lock);

  kfree(bman_res);

@@ -130,17 +131,17 @@ static void i915_ttm_buddy_man_debug(struct ttm_resource_manager *man, struct drm_printer *printer) { struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);

• struct i915_buddy_block *block;

• struct drm_buddy_block *block;

  mutex_lock(&bman->lock); drm_printf(printer, "default_page_size: %lluKiB\n", bman->default_page_size >> 10);

• i915_buddy_print(&bman->mm, printer);

• drm_buddy_print(&bman->mm, printer);

  drm_printf(printer, "reserved:\n"); list_for_each_entry(block, &bman->reserved, link)

• i915_buddy_block_print(&bman->mm, block, printer);
  

• drm_buddy_block_print(&bman->mm, block, printer);
  

  mutex_unlock(&bman->lock); }

@@ -190,7 +191,7 @@ int i915_ttm_buddy_man_init(struct ttm_device *bdev, if (!bman) return -ENOMEM;

• err = i915_buddy_init(&bman->mm, size, chunk_size);

• err = drm_buddy_init(&bman->mm, size, chunk_size); if (err) goto err_free_bman;

@@ -228,7 +229,7 @@ int i915_ttm_buddy_man_fini(struct ttm_device *bdev, unsigned int type) { struct ttm_resource_manager *man = ttm_manager_type(bdev, type); struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);

• struct i915_buddy_mm *mm = &bman->mm;

• struct drm_buddy_mm *mm = &bman->mm; int ret;

  ttm_resource_manager_set_used(man, false);

@@ -240,8 +241,8 @@ int i915_ttm_buddy_man_fini(struct ttm_device *bdev, unsigned int type) ttm_set_driver_manager(bdev, type, NULL);

mutex_lock(&bman->lock);

• i915_buddy_free_list(mm, &bman->reserved);
• i915_buddy_fini(mm);

• drm_buddy_free_list(mm, &bman->reserved);

• drm_buddy_fini(mm); mutex_unlock(&bman->lock);

  ttm_resource_manager_cleanup(man);

@@ -264,11 +265,11 @@ int i915_ttm_buddy_man_reserve(struct ttm_resource_manager *man, u64 start, u64 size) { struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);

• struct i915_buddy_mm *mm = &bman->mm;

• struct drm_buddy_mm *mm = &bman->mm; int ret;

  mutex_lock(&bman->lock);

• ret = i915_buddy_alloc_range(mm, &bman->reserved, start, size);

• ret = drm_buddy_alloc_range(mm, &bman->reserved, start, size); 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 0722d33f3e14..fa644b512c2e 100644 --- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h +++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h @@ -13,7 +13,7 @@

struct ttm_device; struct ttm_resource_manager; -struct i915_buddy_mm; +struct drm_buddy_mm;

/**

• struct i915_ttm_buddy_resource

@@ -28,7 +28,7 @@ struct i915_buddy_mm; struct i915_ttm_buddy_resource { struct ttm_resource base; struct list_head blocks;

• struct i915_buddy_mm *mm;

• struct drm_buddy_mm *mm; };

  /**

diff --git a/include/drm/drm_buddy.h b/include/drm/drm_buddy.h new file mode 100644 index 000000000000..5ce3fc702f80 --- /dev/null +++ b/include/drm/drm_buddy.h @@ -0,0 +1,153 @@ +/* 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>

+#include <drm/drm_print.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__; \

+})

+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;
• 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 {

• /* 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;
• u64 avail;

+};

+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);

+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);

+void drm_buddy_print(struct drm_buddy_mm *mm, struct drm_printer *p); +void drm_buddy_block_print(struct drm_buddy_mm *mm,

• 	   struct drm_buddy_block *block,
  

• 	   struct drm_printer *p);
  

+void drm_buddy_module_exit(void); +int drm_buddy_module_init(void);

+#endif