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

[AMD Public Use]

Hi Christian,

And where is the patch to switch i915 and remove the Intel copy of this?

Creating a patch for the switch.

In general I think that every public function here needs a kerneldoc description what it is all about.

Making a kernel doc description for each public function

Thanks, Arun -----Original Message----- From: Koenig, Christian Christian.Koenig@amd.com Sent: Wednesday, September 22, 2021 12:28 PM To: Paneer Selvam, Arunpravin Arunpravin.PaneerSelvam@amd.com; dri-devel@lists.freedesktop.org; intel-gfx@lists.freedesktop.org; amd-gfx@lists.freedesktop.org; matthew.auld@intel.com; daniel@ffwll.ch; Deucher, Alexander Alexander.Deucher@amd.com Subject: Re: [PATCH 1/2] Enable buddy memory manager support

Am 20.09.21 um 21:20 schrieb Arunpravin:

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

And where is the patch to switch i915 and remove the Intel copy of this?

In general I think that every public function here needs a kerneldoc description what it is all about.

Regards, Christian.

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