On Mon, 2021-06-07 at 19:22 +0100, Matthew Auld wrote:
> Add back our standalone i915_buddy allocator and integrate it into a
> ttm_resource_manager. This will plug into our ttm backend for
> managing
> device local-memory in the next couple of patches.
>
> Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx>
> Cc: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
> ---
>
Since the buddy + selftests have been part of the driver before, I
didn't review them separately, but for the TTM interface, some minor
comments below. With those fixed,
Acked-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
> diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
> b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
> new file mode 100644
> index 000000000000..d7bf37be1932
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
> @@ -0,0 +1,246 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2021 Intel Corporation
> + */
> +
> +#include <linux/slab.h>
> +
> +#include <drm/ttm/ttm_bo_driver.h>
> +#include <drm/ttm/ttm_placement.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 list_head reserved;
> + struct mutex lock;
> +};
> +
> +static inline struct i915_ttm_buddy_manager *
"inline" shouldn't be needed here.
> +to_buddy_manager(struct ttm_resource_manager *man)
> +{
> + return container_of(man, struct i915_ttm_buddy_manager,
> manager);
> +}
> +
> +static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager
> *man,
> + struct ttm_buffer_object *bo,
> + const struct ttm_place *place,
> + struct ttm_resource **res)
> +{
> + struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);
> + struct i915_ttm_buddy_resource *bman_res;
> + struct i915_buddy_mm *mm = &bman->mm;
> + unsigned long n_pages;
> + unsigned int min_order;
> + u64 size;
> + int err;
> +
> + GEM_BUG_ON(place->fpfn || place->lpfn);
> + GEM_BUG_ON(bo->page_alignment < mm->chunk_size);
> +
> + bman_res = kzalloc(sizeof(*bman_res), GFP_KERNEL);
> + if (!bman_res)
> + return -ENOMEM;
> +
> + ttm_resource_init(bo, place, &bman_res->base);
> + INIT_LIST_HEAD(&bman_res->blocks);
> + bman_res->mm = mm;
> +
> + GEM_BUG_ON(!bman_res->base.num_pages);
> + size = bman_res->base.num_pages << PAGE_SHIFT;
> +
> + min_order = ilog2(bo->page_alignment) - ilog2(mm-
> >chunk_size);
> + if (place->flags & TTM_PL_FLAG_CONTIGUOUS) {
> + size = roundup_pow_of_two(size);
> + min_order = ilog2(size) - ilog2(mm->chunk_size);
> + }
> +
> + if (size > mm->size) {
> + err = -E2BIG;
> + goto err_free_res;
> + }
> +
> + n_pages = size >> ilog2(mm->chunk_size);
> +
> + do {
> + struct i915_buddy_block *block;
> + unsigned int order;
> +
> + order = fls(n_pages) - 1;
> + GEM_BUG_ON(order > mm->max_order);
> + GEM_BUG_ON(order < min_order);
> +
> + do {
> + mutex_lock(&bman->lock);
> + block = i915_buddy_alloc(mm, order);
> + mutex_unlock(&bman->lock);
> + if (!IS_ERR(block))
> + break;
> +
> + if (order-- == min_order) {
> + err = -ENXIO;
IIRC, TTM relies on -ENOSPC to retry with evictions.
> + goto err_free_blocks;
> + }
> + } while (1);
> +
> + n_pages -= BIT(order);
> +
> + list_add_tail(&block->link, &bman_res->blocks);
> +
> + if (!n_pages)
> + break;
> + } while (1);
> +
> + *res = &bman_res->base;
> + return 0;
> +
> +err_free_blocks:
> + mutex_lock(&bman->lock);
> + i915_buddy_free_list(mm, &bman_res->blocks);
> + mutex_unlock(&bman->lock);
> +err_free_res:
> + kfree(bman_res);
> + return err;
> +}
> +
/Thomas
