[PATCH 1/3] drm:Enable buddy allocator support
Arunpravin
Arunpravin.PaneerSelvam at amd.com
Wed Oct 13 13:35:34 UTC 2021
Port Intel buddy manager to drm root folder
Implemented range allocation support for the provided order
Implemented TOP-DOWN support
Implemented freeing up unused pages on contiguous allocation
Moved range allocation and freelist pickup into a single function
Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam at amd.com>
---
drivers/gpu/drm/Makefile | 2 +-
drivers/gpu/drm/drm_buddy.c | 705 ++++++++++++++++++++++++++++++++++++
drivers/gpu/drm/drm_drv.c | 3 +
include/drm/drm_buddy.h | 157 ++++++++
4 files changed, 866 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..8cd118574665
--- /dev/null
+++ b/drivers/gpu/drm/drm_buddy.c
@@ -0,0 +1,705 @@
+// 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);
+ kmem_cache_destroy(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);
+}
+
+static 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 from the input list
+ *
+ * @mm: DRM buddy manager
+ * @objects: input list head to free blocks
+ *
+ * drm_buddy_free() called for to free all the blocks
+ * in the list and on each block it looks at the buddy block
+ * and if it is free, coalesce and reforms to a larger block.
+ */
+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);
+
+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_free_unused_pages - free unused pages
+ *
+ * @mm: DRM buddy manager
+ * @actual_size: original size requested
+ * @blocks: output list head to add allocated blocks
+ *
+ * For contiguous allocation, we round up the size to the nearest
+ * power of two value, applications use *exact* size, remaining
+ * portions are unused and it can freed.
+ *
+ * Returns:
+ * 0 on success, error code on failure.
+ */
+int drm_buddy_free_unused_pages(struct drm_buddy_mm *mm,
+ u64 actual_size,
+ struct list_head *blocks)
+{
+ struct drm_buddy_block *block;
+ struct drm_buddy_block *buddy;
+ u64 actual_start;
+ u64 actual_end;
+ LIST_HEAD(dfs);
+ u64 count = 0;
+ int err;
+
+ if (!list_is_singular(blocks))
+ return -EINVAL;
+
+ block = list_first_entry_or_null(blocks,
+ struct drm_buddy_block,
+ link);
+
+ if (!block)
+ return -EINVAL;
+
+ if (actual_size > drm_buddy_block_size(mm, block))
+ return -EINVAL;
+
+ if (actual_size == drm_buddy_block_size(mm, block))
+ return 0;
+
+ list_del(&block->link);
+
+ actual_start = drm_buddy_block_offset(block);
+ actual_end = actual_start + actual_size - 1;
+
+ if (drm_buddy_block_is_allocated(block))
+ mark_free(mm, block);
+
+ list_add(&block->tmp_link, &dfs);
+
+ while (1) {
+ block = list_first_entry_or_null(&dfs,
+ struct drm_buddy_block,
+ tmp_link);
+
+ if (!block)
+ break;
+
+ list_del(&block->tmp_link);
+
+ if (count == actual_size)
+ return 0;
+
+ if (contains(actual_start, actual_end, drm_buddy_block_offset(block),
+ (drm_buddy_block_offset(block) + drm_buddy_block_size(mm, block) - 1))) {
+ BUG_ON(!drm_buddy_block_is_free(block));
+ /* Allocate only required blocks */
+ mark_allocated(block);
+ mm->avail -= drm_buddy_block_size(mm, block);
+ list_add_tail(&block->link, blocks);
+ count += drm_buddy_block_size(mm, block);
+ continue;
+ }
+
+ if (drm_buddy_block_order(block) == 0)
+ 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);
+ }
+
+ return -ENOSPC;
+
+err_undo:
+ buddy = get_buddy(block);
+ if (buddy &&
+ (drm_buddy_block_is_free(block) &&
+ drm_buddy_block_is_free(buddy)))
+ __drm_buddy_free(mm, block);
+ return err;
+}
+EXPORT_SYMBOL(drm_buddy_free_unused_pages);
+
+static struct drm_buddy_block *
+alloc_range(struct drm_buddy_mm *mm,
+ u64 start, u64 end,
+ unsigned int order)
+{
+ struct drm_buddy_block *block;
+ struct drm_buddy_block *buddy;
+ LIST_HEAD(dfs);
+ int err;
+ int i;
+
+ end = end - 1;
+
+ for (i = 0; i < mm->n_roots; ++i)
+ list_add_tail(&mm->roots[i]->tmp_link, &dfs);
+
+ 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);
+
+ if (drm_buddy_block_order(block) < order)
+ continue;
+
+ 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))
+ continue;
+
+ if (contains(start, end, block_start, block_end)
+ && order == drm_buddy_block_order(block)) {
+ /*
+ * Find the free block within the range.
+ */
+ if (drm_buddy_block_is_free(block))
+ return block;
+
+ continue;
+ }
+
+ if (!drm_buddy_block_is_split(block)) {
+ err = split_block(mm, block);
+ if (unlikely(err))
+ goto err_undo;
+ }
+
+ list_add(&block->left->tmp_link, &dfs);
+ list_add(&block->right->tmp_link, &dfs);
+ } while (1);
+
+ return ERR_PTR(-ENOSPC);
+
+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);
+ return ERR_PTR(err);
+}
+
+static struct drm_buddy_block *
+get_maxblock(struct list_head *head)
+{
+ struct drm_buddy_block *max_block = NULL, *node;
+
+ max_block = list_first_entry_or_null(head,
+ struct drm_buddy_block,
+ link);
+ if (!max_block)
+ return NULL;
+
+ list_for_each_entry(node, head, link) {
+ if (drm_buddy_block_offset(node) >
+ drm_buddy_block_offset(max_block))
+ max_block = node;
+ }
+
+ return max_block;
+}
+
+static struct drm_buddy_block *
+alloc_from_freelist(struct drm_buddy_mm *mm,
+ unsigned int order,
+ unsigned long flags)
+{
+ struct drm_buddy_block *block = NULL;
+ unsigned int i;
+ int err;
+
+ for (i = order; i <= mm->max_order; ++i) {
+ if (flags & DRM_BUDDY_TOPDOWN_ALLOCATION) {
+ if (!list_empty(&mm->free_list[i])) {
+ block = get_maxblock(&mm->free_list[i]);
+
+ if (block)
+ break;
+ }
+ } else {
+ if (!list_empty(&mm->free_list[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 err_undo;
+
+ block = block->right;
+ i--;
+ }
+
+ return block;
+
+err_undo:
+ if (i != order)
+ __drm_buddy_free(mm, block);
+ return ERR_PTR(err);
+}
+
+/**
+ * drm_buddy_alloc - allocate power-of-two blocks
+ *
+ * @mm: DRM buddy manager to allocate from
+ * @start: start of the allowed range for this block
+ * @end: end of the allowed range for this block
+ * @size: size of the allocation
+ * @min_page_size: alignment of the allocation
+ * @blocks: output list head to add allocated blocks
+ * @flags: DRM_BUDDY_*_ALLOCATION flags
+ *
+ * alloc_range() called for range limitations, which traverses
+ * the binary tree and picks the desired block, intended for
+ * allocating portions of CPU mappable region and for
+ * pre-allocating portions of the address space, for example to
+ * reserve a block for the initial framebuffer.
+ *
+ * alloc_from_freelist() called for *no* range restrictions,
+ * which easy picks the block from the freelist.
+ *
+ * we allocate blocks in order, order value here translates to:
+ *
+ * 0 = 2^0 * mm->chunk_size
+ * 1 = 2^1 * mm->chunk_size
+ * 2 = 2^2 * mm->chunk_size
+ *
+ * Returns:
+ * 0 on success, error code on failure.
+ */
+int drm_buddy_alloc(struct drm_buddy_mm *mm,
+ u64 start, u64 end, u64 size,
+ u64 min_page_size,
+ struct list_head *blocks,
+ unsigned long flags)
+{
+ struct drm_buddy_block *block = NULL;
+ unsigned int min_order, order;
+ unsigned long pages;
+ LIST_HEAD(allocated);
+ int err;
+
+ if (size < mm->chunk_size)
+ return -EINVAL;
+
+ if (!IS_ALIGNED(size | start, mm->chunk_size))
+ return -EINVAL;
+
+ if (check_range_overflow(start, size, mm->size))
+ return -EINVAL;
+
+ pages = size >> ilog2(mm->chunk_size);
+ min_order = ilog2(min_page_size) - ilog2(mm->chunk_size);
+
+ do {
+ order = fls(pages) - 1;
+ BUG_ON(order > mm->max_order);
+ BUG_ON(order < min_order);
+
+ do {
+ if (flags & DRM_BUDDY_RANGE_ALLOCATION)
+ /* Allocate traversing within the range */
+ block = alloc_range(mm, start, end, order);
+ else
+ /* Allocate from freelist */
+ block = alloc_from_freelist(mm, order, flags);
+
+ if (!IS_ERR(block))
+ break;
+
+ if (order-- == min_order) {
+ err = -ENOSPC;
+ goto err_free;
+ }
+ } while (1);
+
+ mark_allocated(block);
+ mm->avail -= drm_buddy_block_size(mm, block);
+ kmemleak_update_trace(block);
+
+ list_add_tail(&block->link, &allocated);
+
+ pages -= BIT(order);
+
+ if (!pages)
+ break;
+ } while (1);
+
+ list_splice_tail(&allocated, blocks);
+ return 0;
+
+err_free:
+ drm_buddy_free_list(mm, &allocated);
+ return err;
+}
+EXPORT_SYMBOL(drm_buddy_alloc);
+
+/**
+ * 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 8804ec7d3215..2d2462aa8d52 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -43,6 +43,7 @@
#include <drm/drm_managed.h>
#include <drm/drm_mode_object.h>
#include <drm/drm_print.h>
+#include <drm/drm_buddy.h>
#include "drm_crtc_internal.h"
#include "drm_internal.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/include/drm/drm_buddy.h b/include/drm/drm_buddy.h
new file mode 100644
index 000000000000..e5a9a8cfdf42
--- /dev/null
+++ b/include/drm/drm_buddy.h
@@ -0,0 +1,157 @@
+/* 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 check_range_overflow(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__; \
+})
+
+#define DRM_BUDDY_TOPDOWN_ALLOCATION (1 << 0)
+#define DRM_BUDDY_RANGE_ALLOCATION (1 << 1)
+
+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);
+
+int drm_buddy_alloc(struct drm_buddy_mm *mm,
+ u64 start, u64 end, u64 size,
+ u64 min_page_size,
+ struct list_head *blocks,
+ unsigned long flags);
+
+int drm_buddy_free_unused_pages(struct drm_buddy_mm *mm,
+ u64 actual_size,
+ struct list_head *blocks);
+
+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
--
2.25.1
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