[PATCH 1/2] Enable buddy memory manager support
Paneer Selvam, Arunpravin
Arunpravin.PaneerSelvam at amd.com
Thu Sep 23 05:59:19 UTC 2021
[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 at amd.com>
Sent: Wednesday, September 22, 2021 12:28 PM
To: Paneer Selvam, Arunpravin <Arunpravin.PaneerSelvam at amd.com>; dri-devel at lists.freedesktop.org; intel-gfx at lists.freedesktop.org; amd-gfx at lists.freedesktop.org; matthew.auld at intel.com; daniel at ffwll.ch; Deucher, Alexander <Alexander.Deucher at 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 at 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
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