[Intel-gfx] [PATCH v2 10/15] drm/i915/ttm: Introduce a TTM i915 gem object backend
Matthew Auld
matthew.william.auld at gmail.com
Wed May 19 09:53:25 UTC 2021
On Tue, 18 May 2021 at 09:28, Thomas Hellström
<thomas.hellstrom at linux.intel.com> wrote:
>
> Most logical place to introduce TTM buffer objects is as an i915
> gem object backend. We need to add some ops to account for added
> functionality like delayed delete and LRU list manipulation.
>
> Initially we support only LMEM and SYSTEM memory, but SYSTEM
> (which in this case means evicted LMEM objects) is not
> visible to i915 GEM yet. The plan is to move the i915 gem system region
> over to the TTM system memory type in upcoming patches.
>
> We set up GPU bindings directly both from LMEM and from the system region,
> as there is no need to use the legacy TTM_TT memory type. We reserve
> that for future porting of GGTT bindings to TTM.
>
> Remove the old lmem backend.
>
> Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> ---
> v2:
> - Break out needed TTM functionality to a separate patch (Reported by
> Christian König).
> - Fix an unhandled error (Reported by Matthew Auld and Maarten Lankhorst)
> - Remove a stray leftover sg_table allocation (Reported by Matthew Auld)
> - Use ttm_tt_unpopulate() rather than ttm_tt_destroy() in the purge path
> as some TTM functionality relies on having a ttm_tt present for !is_iomem.
> ---
> drivers/gpu/drm/i915/Makefile | 1 +
> drivers/gpu/drm/i915/gem/i915_gem_lmem.c | 84 ---
> drivers/gpu/drm/i915/gem/i915_gem_lmem.h | 5 -
> drivers/gpu/drm/i915/gem/i915_gem_object.c | 125 +++--
> drivers/gpu/drm/i915/gem/i915_gem_object.h | 9 +
> .../gpu/drm/i915/gem/i915_gem_object_types.h | 18 +
> drivers/gpu/drm/i915/gem/i915_gem_region.c | 6 +-
> drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 519 ++++++++++++++++++
> drivers/gpu/drm/i915/gem/i915_gem_ttm.h | 48 ++
> drivers/gpu/drm/i915/gt/intel_region_lmem.c | 3 +-
> drivers/gpu/drm/i915/i915_gem.c | 5 +-
> drivers/gpu/drm/i915/intel_memory_region.c | 1 -
> drivers/gpu/drm/i915/intel_memory_region.h | 1 -
> drivers/gpu/drm/i915/intel_region_ttm.c | 5 +-
> drivers/gpu/drm/i915/intel_region_ttm.h | 7 +-
> 15 files changed, 696 insertions(+), 141 deletions(-)
> create mode 100644 drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> create mode 100644 drivers/gpu/drm/i915/gem/i915_gem_ttm.h
>
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 958ccc1edfed..ef0d884a9e2d 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -155,6 +155,7 @@ gem-y += \
> gem/i915_gem_stolen.o \
> gem/i915_gem_throttle.o \
> gem/i915_gem_tiling.o \
> + gem/i915_gem_ttm.o \
> gem/i915_gem_ttm_bo_util.o \
> gem/i915_gem_userptr.o \
> gem/i915_gem_wait.o \
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_lmem.c b/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
> index 3b4aa28a076d..2b8cd15de1d9 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
> @@ -4,74 +4,10 @@
> */
>
> #include "intel_memory_region.h"
> -#include "intel_region_ttm.h"
> #include "gem/i915_gem_region.h"
> #include "gem/i915_gem_lmem.h"
> #include "i915_drv.h"
>
> -static void lmem_put_pages(struct drm_i915_gem_object *obj,
> - struct sg_table *pages)
> -{
> - intel_region_ttm_node_free(obj->mm.region, obj->mm.st_mm_node);
> - obj->mm.dirty = false;
> - sg_free_table(pages);
> - kfree(pages);
> -}
> -
> -static int lmem_get_pages(struct drm_i915_gem_object *obj)
> -{
> - unsigned int flags;
> - struct sg_table *pages;
> -
> - flags = I915_ALLOC_MIN_PAGE_SIZE;
> - if (obj->flags & I915_BO_ALLOC_CONTIGUOUS)
> - flags |= I915_ALLOC_CONTIGUOUS;
> -
> - obj->mm.st_mm_node = intel_region_ttm_node_alloc(obj->mm.region,
> - obj->base.size,
> - flags);
> - if (IS_ERR(obj->mm.st_mm_node))
> - return PTR_ERR(obj->mm.st_mm_node);
> -
> - /* Range manager is always contigous */
> - if (obj->mm.region->is_range_manager)
> - obj->flags |= I915_BO_ALLOC_CONTIGUOUS;
> - pages = intel_region_ttm_node_to_st(obj->mm.region, obj->mm.st_mm_node);
> - if (IS_ERR(pages)) {
> - intel_region_ttm_node_free(obj->mm.region, obj->mm.st_mm_node);
> - return PTR_ERR(pages);
> - }
> -
> - __i915_gem_object_set_pages(obj, pages, i915_sg_dma_sizes(pages->sgl));
> -
> - if (obj->flags & I915_BO_ALLOC_CPU_CLEAR) {
> - void __iomem *vaddr =
> - i915_gem_object_lmem_io_map(obj, 0, obj->base.size);
> -
> - if (!vaddr) {
> - struct sg_table *pages =
> - __i915_gem_object_unset_pages(obj);
> -
> - if (!IS_ERR_OR_NULL(pages))
> - lmem_put_pages(obj, pages);
> - }
> -
> - memset_io(vaddr, 0, obj->base.size);
> - io_mapping_unmap(vaddr);
> - }
> -
> - return 0;
> -}
> -
> -const struct drm_i915_gem_object_ops i915_gem_lmem_obj_ops = {
> - .name = "i915_gem_object_lmem",
> - .flags = I915_GEM_OBJECT_HAS_IOMEM,
> -
> - .get_pages = lmem_get_pages,
> - .put_pages = lmem_put_pages,
> - .release = i915_gem_object_release_memory_region,
> -};
> -
> void __iomem *
> i915_gem_object_lmem_io_map(struct drm_i915_gem_object *obj,
> unsigned long n,
> @@ -103,23 +39,3 @@ i915_gem_object_create_lmem(struct drm_i915_private *i915,
> return i915_gem_object_create_region(i915->mm.regions[INTEL_REGION_LMEM],
> size, flags);
> }
> -
> -int __i915_gem_lmem_object_init(struct intel_memory_region *mem,
> - struct drm_i915_gem_object *obj,
> - resource_size_t size,
> - unsigned int flags)
> -{
> - static struct lock_class_key lock_class;
> - struct drm_i915_private *i915 = mem->i915;
> -
> - drm_gem_private_object_init(&i915->drm, &obj->base, size);
> - i915_gem_object_init(obj, &i915_gem_lmem_obj_ops, &lock_class, flags);
> -
> - obj->read_domains = I915_GEM_DOMAIN_WC | I915_GEM_DOMAIN_GTT;
> -
> - i915_gem_object_set_cache_coherency(obj, I915_CACHE_NONE);
> -
> - i915_gem_object_init_memory_region(obj, mem);
> -
> - return 0;
> -}
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_lmem.h b/drivers/gpu/drm/i915/gem/i915_gem_lmem.h
> index fac6bc5a5ebb..ea76fd11ccb0 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_lmem.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_lmem.h
> @@ -26,9 +26,4 @@ i915_gem_object_create_lmem(struct drm_i915_private *i915,
> resource_size_t size,
> unsigned int flags);
>
> -int __i915_gem_lmem_object_init(struct intel_memory_region *mem,
> - struct drm_i915_gem_object *obj,
> - resource_size_t size,
> - unsigned int flags);
> -
> #endif /* !__I915_GEM_LMEM_H */
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c b/drivers/gpu/drm/i915/gem/i915_gem_object.c
> index c8953e3f5c70..8580996107ce 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c
> @@ -172,7 +172,7 @@ static void i915_gem_close_object(struct drm_gem_object *gem, struct drm_file *f
> }
> }
>
> -static void __i915_gem_free_object_rcu(struct rcu_head *head)
> +void __i915_gem_free_object_rcu(struct rcu_head *head)
> {
> struct drm_i915_gem_object *obj =
> container_of(head, typeof(*obj), rcu);
> @@ -208,59 +208,69 @@ static void __i915_gem_object_free_mmaps(struct drm_i915_gem_object *obj)
> }
> }
>
> -static void __i915_gem_free_objects(struct drm_i915_private *i915,
> - struct llist_node *freed)
> +void __i915_gem_free_object(struct drm_i915_gem_object *obj)
> {
> - struct drm_i915_gem_object *obj, *on;
> + trace_i915_gem_object_destroy(obj);
>
> - llist_for_each_entry_safe(obj, on, freed, freed) {
> - trace_i915_gem_object_destroy(obj);
> + if (!list_empty(&obj->vma.list)) {
> + struct i915_vma *vma;
> +
> + /*
> + * Note that the vma keeps an object reference while
> + * it is active, so it *should* not sleep while we
> + * destroy it. Our debug code errs insits it *might*.
> + * For the moment, play along.
> + */
> + spin_lock(&obj->vma.lock);
> + while ((vma = list_first_entry_or_null(&obj->vma.list,
> + struct i915_vma,
> + obj_link))) {
> + GEM_BUG_ON(vma->obj != obj);
> + spin_unlock(&obj->vma.lock);
>
> - if (!list_empty(&obj->vma.list)) {
> - struct i915_vma *vma;
> + __i915_vma_put(vma);
>
> - /*
> - * Note that the vma keeps an object reference while
> - * it is active, so it *should* not sleep while we
> - * destroy it. Our debug code errs insits it *might*.
> - * For the moment, play along.
> - */
> spin_lock(&obj->vma.lock);
> - while ((vma = list_first_entry_or_null(&obj->vma.list,
> - struct i915_vma,
> - obj_link))) {
> - GEM_BUG_ON(vma->obj != obj);
> - spin_unlock(&obj->vma.lock);
> + }
> + spin_unlock(&obj->vma.lock);
> + }
>
> - __i915_vma_put(vma);
> + __i915_gem_object_free_mmaps(obj);
>
> - spin_lock(&obj->vma.lock);
> - }
> - spin_unlock(&obj->vma.lock);
> - }
> + GEM_BUG_ON(!list_empty(&obj->lut_list));
>
> - __i915_gem_object_free_mmaps(obj);
> + atomic_set(&obj->mm.pages_pin_count, 0);
> + __i915_gem_object_put_pages(obj);
> + GEM_BUG_ON(i915_gem_object_has_pages(obj));
> + bitmap_free(obj->bit_17);
>
> - GEM_BUG_ON(!list_empty(&obj->lut_list));
> + if (obj->base.import_attach)
> + drm_prime_gem_destroy(&obj->base, NULL);
>
> - atomic_set(&obj->mm.pages_pin_count, 0);
> - __i915_gem_object_put_pages(obj);
> - GEM_BUG_ON(i915_gem_object_has_pages(obj));
> - bitmap_free(obj->bit_17);
> + drm_gem_free_mmap_offset(&obj->base);
>
> - if (obj->base.import_attach)
> - drm_prime_gem_destroy(&obj->base, NULL);
> + if (obj->ops->release)
> + obj->ops->release(obj);
>
> - drm_gem_free_mmap_offset(&obj->base);
> + if (obj->mm.n_placements > 1)
> + kfree(obj->mm.placements);
>
> - if (obj->ops->release)
> - obj->ops->release(obj);
> + if (obj->resv_shared_from)
> + i915_vm_resv_put(obj->resv_shared_from);
> +}
>
> - if (obj->mm.n_placements > 1)
> - kfree(obj->mm.placements);
> +static void __i915_gem_free_objects(struct drm_i915_private *i915,
> + struct llist_node *freed)
> +{
> + struct drm_i915_gem_object *obj, *on;
>
> - if (obj->resv_shared_from)
> - i915_vm_resv_put(obj->resv_shared_from);
> + llist_for_each_entry_safe(obj, on, freed, freed) {
> + might_sleep();
> + if (obj->ops->delayed_free) {
> + obj->ops->delayed_free(obj);
> + continue;
> + }
> + __i915_gem_free_object(obj);
>
> /* But keep the pointer alive for RCU-protected lookups */
> call_rcu(&obj->rcu, __i915_gem_free_object_rcu);
> @@ -318,6 +328,7 @@ static void i915_gem_free_object(struct drm_gem_object *gem_obj)
> * worker and performing frees directly from subsequent allocations for
> * crude but effective memory throttling.
> */
> +
> if (llist_add(&obj->freed, &i915->mm.free_list))
> queue_work(i915->wq, &i915->mm.free_work);
> }
> @@ -410,6 +421,42 @@ int i915_gem_object_read_from_page(struct drm_i915_gem_object *obj, u64 offset,
> return 0;
> }
>
> +/**
> + * i915_gem_object_evictable - Whether object is likely evictable after unbind.
> + * @obj: The object to check
> + *
> + * This function checks whether the object is likely unvictable after unbind.
> + * If the object is not locked when checking, the result is only advisory.
> + * If the object is locked when checking, and the function returns true,
> + * then an eviction should indeed be possible. But since unlocked vma
> + * unpinning and unbinding is currently possible, the object can actually
> + * become evictable even if this function returns false.
> + *
> + * Return: true if the object may be evictable. False otherwise.
> + */
> +bool i915_gem_object_evictable(struct drm_i915_gem_object *obj)
> +{
> + struct i915_vma *vma;
> + int pin_count = atomic_read(&obj->mm.pages_pin_count);
> +
> + if (!pin_count)
> + return true;
> +
> + spin_lock(&obj->vma.lock);
> + list_for_each_entry(vma, &obj->vma.list, obj_link) {
> + if (i915_vma_is_pinned(vma)) {
> + spin_unlock(&obj->vma.lock);
> + return false;
> + }
> + if (atomic_read(&vma->pages_count))
> + pin_count--;
Can't pages_count be > 1, which would also be reflected in
pages_pin_count? The vma_pin path looks very complex.
> + }
> + spin_unlock(&obj->vma.lock);
> + GEM_WARN_ON(pin_count < 0);
> +
> + return pin_count == 0;
> +}
> +
> void i915_gem_init__objects(struct drm_i915_private *i915)
> {
> INIT_WORK(&i915->mm.free_work, __i915_gem_free_work);
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> index 2ebd79537aea..ae5930e307d5 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> @@ -200,6 +200,9 @@ static inline bool i915_gem_object_trylock(struct drm_i915_gem_object *obj)
>
> static inline void i915_gem_object_unlock(struct drm_i915_gem_object *obj)
> {
> + if (obj->ops->adjust_lru)
> + obj->ops->adjust_lru(obj);
Interesting, so we bump the lru even when we just drop the lock?
> +
> dma_resv_unlock(obj->base.resv);
> }
>
> @@ -587,6 +590,12 @@ int i915_gem_object_read_from_page(struct drm_i915_gem_object *obj, u64 offset,
>
> bool i915_gem_object_is_shmem(const struct drm_i915_gem_object *obj);
>
> +void __i915_gem_free_object_rcu(struct rcu_head *head);
> +
> +void __i915_gem_free_object(struct drm_i915_gem_object *obj);
> +
> +bool i915_gem_object_evictable(struct drm_i915_gem_object *obj);
> +
> #ifdef CONFIG_MMU_NOTIFIER
> static inline bool
> i915_gem_object_is_userptr(struct drm_i915_gem_object *obj)
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
> index 98f69d8fd37d..b350765e1935 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
> @@ -63,6 +63,20 @@ struct drm_i915_gem_object_ops {
> const struct drm_i915_gem_pwrite *arg);
>
> int (*dmabuf_export)(struct drm_i915_gem_object *obj);
> +
> + /**
> + * adjust_lru - notify that the madvise value was updated
> + * @obj: The gem object
> + *
> + * The madvise value may have been updated, or object was recently
> + * referenced so act accordingly (Perhaps changing an LRU list etc).
> + */
> + void (*adjust_lru)(struct drm_i915_gem_object *obj);
> +
> + /**
> + * delayed_free - Override the default delayed free implementation
> + */
> + void (*delayed_free)(struct drm_i915_gem_object *obj);
> void (*release)(struct drm_i915_gem_object *obj);
>
> const char *name; /* friendly name for debug, e.g. lockdep classes */
> @@ -307,6 +321,10 @@ struct drm_i915_gem_object {
> bool dirty:1;
> } mm;
>
> + struct {
> + struct sg_table *cached_io_st;
> + } ttm;
> +
> /** Record of address bit 17 of each page at last unbind. */
> unsigned long *bit_17;
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_region.c b/drivers/gpu/drm/i915/gem/i915_gem_region.c
> index f25e6646c5b7..d1f1840540dd 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_region.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_region.c
> @@ -18,11 +18,7 @@ void i915_gem_object_init_memory_region(struct drm_i915_gem_object *obj,
>
> mutex_lock(&mem->objects.lock);
>
> - if (obj->flags & I915_BO_ALLOC_VOLATILE)
> - list_add(&obj->mm.region_link, &mem->objects.purgeable);
> - else
> - list_add(&obj->mm.region_link, &mem->objects.list);
> -
> + list_add(&obj->mm.region_link, &mem->objects.list);
> mutex_unlock(&mem->objects.lock);
> }
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> new file mode 100644
> index 000000000000..790f5ec45c4d
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> @@ -0,0 +1,519 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2021 Intel Corporation
> + */
> +
> +#include <drm/ttm/ttm_bo_driver.h>
> +#include <drm/ttm/ttm_placement.h>
> +
> +#include "i915_drv.h"
> +#include "intel_memory_region.h"
> +#include "intel_region_ttm.h"
> +
> +#include "gem/i915_gem_object.h"
> +#include "gem/i915_gem_region.h"
> +#include "gem/i915_gem_ttm.h"
> +#include "gem/i915_gem_ttm_bo_util.h"
> +
> +#define I915_PL_LMEM0 TTM_PL_PRIV
> +#define I915_PL_SYSTEM TTM_PL_SYSTEM
> +#define I915_PL_STOLEN TTM_PL_VRAM
> +#define I915_PL_GGTT TTM_PL_TT
> +
> +#define I915_TTM_PRIO_PURGE 0
> +#define I915_TTM_PRIO_NO_PAGES 1
> +#define I915_TTM_PRIO_HAS_PAGES 2
> +
> +/**
> + * struct i915_ttm_tt - TTM page vector with additional private information
> + * @ttm: The base TTM page vector.
> + * @dev: The struct device used for dma mapping and unmapping.
> + * @cached_st: The cached scatter-gather table.
> + *
> + * Note that DMA may be going on right up to the point where the page-
> + * vector is unpopulated in delayed destroy. Hence keep the
> + * scatter-gather table mapped and cached up to that point. This is
> + * different from the cached gem object io scatter-gather table which
> + * doesn't have an associated dma mapping.
> + */
> +struct i915_ttm_tt {
What is the _tt here btw? Translation table? We also have use_tt
elsewhere. ttm_tt looks like it just holds an array of pages, and
associated data? ttm_pv?
> + struct ttm_tt ttm;
> + struct device *dev;
> + struct sg_table *cached_st;
> +};
> +
> +static const struct ttm_place lmem0_sys_placement_flags[] = {
> + {
> + .fpfn = 0,
> + .lpfn = 0,
> + .mem_type = I915_PL_LMEM0,
> + .flags = 0,
> + }, {
> + .fpfn = 0,
> + .lpfn = 0,
> + .mem_type = I915_PL_SYSTEM,
> + .flags = 0,
> + }
> +};
> +
> +struct ttm_placement i915_lmem0_placement = {
> + .num_placement = 1,
> + .placement = &lmem0_sys_placement_flags[0],
> + .num_busy_placement = 1,
> + .busy_placement = &lmem0_sys_placement_flags[0],
> +};
> +
> +struct ttm_placement i915_lmem0_sys_placement = {
> + .num_placement = 1,
> + .placement = &lmem0_sys_placement_flags[0],
> + .num_busy_placement = 2,
> + .busy_placement = &lmem0_sys_placement_flags[0],
> +};
> +
> +struct ttm_placement i915_sys_placement = {
> + .num_placement = 1,
> + .placement = &lmem0_sys_placement_flags[1],
> + .num_busy_placement = 1,
> + .busy_placement = &lmem0_sys_placement_flags[1],
> +};
> +
> +static void i915_ttm_adjust_lru(struct drm_i915_gem_object *obj);
> +
> +static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo,
> + uint32_t page_flags)
> +{
> + struct ttm_resource_manager *man =
> + ttm_manager_type(bo->bdev, bo->mem.mem_type);
> + struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
> + struct i915_ttm_tt *i915_tt;
> + int ret;
> +
> + i915_tt = kzalloc(sizeof(*i915_tt), GFP_KERNEL);
> + if (!i915_tt)
> + return NULL;
> +
> + if (obj->flags & I915_BO_ALLOC_CPU_CLEAR &&
> + man->use_tt)
> + page_flags |= TTM_PAGE_FLAG_ZERO_ALLOC;
> +
> + ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags, ttm_cached);
> + if (ret) {
> + kfree(i915_tt);
> + return NULL;
> + }
> +
> + i915_tt->dev = obj->base.dev->dev;
> +
> + return &i915_tt->ttm;
> +}
> +
> +static void i915_ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm)
> +{
> + struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
> +
> + if (i915_tt->cached_st) {
> + dma_unmap_sgtable(i915_tt->dev, i915_tt->cached_st,
> + DMA_BIDIRECTIONAL, 0);
> + sg_free_table(i915_tt->cached_st);
> + kfree(i915_tt->cached_st);
> + i915_tt->cached_st = NULL;
> + }
> + ttm_pool_free(&bdev->pool, ttm);
> +}
> +
> +static void i915_ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *ttm)
> +{
> + struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
> +
> + ttm_tt_destroy_common(bdev, ttm);
> + kfree(i915_tt);
> +}
> +
> +static bool i915_ttm_eviction_valuable(struct ttm_buffer_object *bo,
> + const struct ttm_place *place)
> +{
> + struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
> +
> + /* Will do for now. Our pinned objects are still on TTM's LRU lists */
> + if (!i915_gem_object_evictable(obj))
> + return false;
> +
> + /* This isn't valid with a buddy allocator */
> + return ttm_bo_eviction_valuable(bo, place);
> +}
> +
> +static void i915_ttm_evict_flags(struct ttm_buffer_object *bo,
> + struct ttm_placement *placement)
> +{
> + *placement = i915_sys_placement;
What's the story here?
> +}
> +
> +static int i915_ttm_move_notify(struct ttm_buffer_object *bo)
> +{
> + struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
> + int ret;
> +
> + ret = i915_gem_object_unbind(obj, I915_GEM_OBJECT_UNBIND_ACTIVE);
> + if (ret)
> + return ret;
> +
> + ret = __i915_gem_object_put_pages(obj);
> + if (ret)
> + return ret;
> +
> + return 0;
> +}
> +
> +static void i915_ttm_free_cached_io_st(struct drm_i915_gem_object *obj)
> +{
> + if (obj->ttm.cached_io_st) {
> + sg_free_table(obj->ttm.cached_io_st);
> + kfree(obj->ttm.cached_io_st);
> + obj->ttm.cached_io_st = NULL;
> + }
> +}
> +
> +static void i915_ttm_purge(struct drm_i915_gem_object *obj)
> +{
> + struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
> +
> + if (obj->mm.madv == __I915_MADV_PURGED)
> + return;
> +
> + i915_ttm_free_cached_io_st(obj);
> +
> + ttm_resource_free(bo, &bo->mem);
> + if (bo->ttm) {
> + ttm_tt_unpopulate(bo->bdev, bo->ttm);
> + bo->ttm->page_flags |= TTM_PAGE_FLAG_ZERO_ALLOC;
> + }
> +
> + obj->mm.madv = __I915_MADV_PURGED;
> +}
> +
> +static void i915_ttm_swap_notify(struct ttm_buffer_object *bo)
> +{
> + struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
> + int ret = i915_ttm_move_notify(bo);
> +
> + GEM_WARN_ON(ret);
> + GEM_WARN_ON(obj->ttm.cached_io_st);
> + if (!ret && obj->mm.madv != I915_MADV_WILLNEED)
> + i915_ttm_purge(obj);
> +}
> +
> +static void i915_ttm_delete_mem_notify(struct ttm_buffer_object *bo)
> +{
> + struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
> +
> + if (likely(obj)) {
> + /* This releases all gem object bindings to the backend. */
> + __i915_gem_free_object(obj);
> + }
> +}
> +
> +static struct intel_memory_region *
> +i915_ttm_region(struct ttm_device *bdev, int ttm_mem_type)
> +{
> + struct drm_i915_private *i915 = container_of(bdev, typeof(*i915), bdev);
> +
> + /* There's some room for optimization here... */
> + GEM_BUG_ON(ttm_mem_type != I915_PL_SYSTEM &&
> + ttm_mem_type < I915_PL_LMEM0);
> + if (ttm_mem_type == I915_PL_SYSTEM)
> + return intel_memory_region_lookup(i915, INTEL_MEMORY_SYSTEM,
> + 0);
So at the moment we just have lmem using the new ttm backend, right?
Stolen and system are unchanged?
> +
> + return intel_memory_region_lookup(i915, INTEL_MEMORY_LOCAL,
> + ttm_mem_type - I915_PL_LMEM0);
> +}
> +
> +static struct sg_table *i915_ttm_tt_get_st(struct ttm_tt *ttm)
> +{
> + struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
> + struct scatterlist *sg;
> + struct sg_table *st;
> + int ret;
> +
> + if (i915_tt->cached_st)
> + return i915_tt->cached_st;
> +
> + st = kzalloc(sizeof(*st), GFP_KERNEL);
> + if (!st)
> + return ERR_PTR(-ENOMEM);
> +
> + sg = __sg_alloc_table_from_pages
> + (st, ttm->pages, ttm->num_pages, 0,
> + (unsigned long)ttm->num_pages << PAGE_SHIFT,
> + i915_sg_segment_size(), NULL, 0, GFP_KERNEL);
> + if (IS_ERR(sg)) {
> + kfree(st);
> + return ERR_CAST(sg);
> + }
> +
> + ret = dma_map_sgtable(i915_tt->dev, st, DMA_BIDIRECTIONAL, 0);
> + if (ret) {
> + sg_free_table(st);
> + kfree(st);
> + return ERR_PTR(ret);
> + }
> +
> + i915_tt->cached_st = st;
> + return st;
> +}
> +
> +static struct sg_table *
> +i915_ttm_resource_get_st(struct drm_i915_gem_object *obj,
> + struct ttm_resource *res)
> +{
> + struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
> + struct ttm_resource_manager *man =
> + ttm_manager_type(bo->bdev, res->mem_type);
> +
> + if (man->use_tt)
> + return i915_ttm_tt_get_st(bo->ttm);
> +
> + return intel_region_ttm_node_to_st(obj->mm.region, res->mm_node);
> +}
> +
> +static int i915_ttm_move(struct ttm_buffer_object *bo, bool evict,
> + struct ttm_operation_ctx *ctx,
> + struct ttm_resource *new_mem,
> + struct ttm_place *hop)
> +{
> + struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
> + struct ttm_resource_manager *new_man =
> + ttm_manager_type(bo->bdev, new_mem->mem_type);
> + struct ttm_resource_manager *old_man =
> + ttm_manager_type(bo->bdev, bo->mem.mem_type);
> + struct intel_memory_region *new_reg, *old_reg;
> + union {
> + struct i915_ttm_kmap_iter_tt tt;
> + struct i915_ttm_kmap_iter_iomap io;
> + } _new_iter, _old_iter;
> + struct i915_ttm_kmap_iter *new_iter, *old_iter;
> + struct sg_table *new_st;
> + int ret;
> +
> + new_reg = i915_ttm_region(bo->bdev, new_mem->mem_type);
> + old_reg = i915_ttm_region(bo->bdev, bo->mem.mem_type);
> + GEM_BUG_ON(!new_reg || !old_reg);
> +
> + /* Sync for now. We could do the actual copy async. */
> + ret = ttm_bo_wait_ctx(bo, ctx);
> + if (ret)
> + return ret;
> +
> + ret = i915_ttm_move_notify(bo);
> + if (ret)
> + return ret;
> +
> + if (obj->mm.madv != I915_MADV_WILLNEED) {
> + i915_ttm_purge(obj);
> + ttm_resource_free(bo, new_mem);
> + return 0;
> + }
> +
> + /* Populate ttm with pages if needed. Typically system memory. */
> + if (new_man->use_tt && bo->ttm) {
> + ret = ttm_tt_populate(bo->bdev, bo->ttm, ctx);
> + if (ret)
> + return ret;
> + }
> +
> + new_st = i915_ttm_resource_get_st(obj, new_mem);
> + if (IS_ERR(new_st))
> + return PTR_ERR(new_st);
> +
> + new_iter = new_man->use_tt ?
> + i915_ttm_kmap_iter_tt_init(&_new_iter.tt, bo->ttm) :
> + i915_ttm_kmap_iter_iomap_init(&_new_iter.io, &new_reg->iomap,
> + new_st, new_reg->region.start);
> +
> + old_iter = old_man->use_tt ?
> + i915_ttm_kmap_iter_tt_init(&_old_iter.tt, bo->ttm) :
> + i915_ttm_kmap_iter_iomap_init(&_old_iter.io, &old_reg->iomap,
> + obj->ttm.cached_io_st,
> + old_reg->region.start);
> +
> + i915_ttm_move_memcpy(bo, new_mem, new_iter, old_iter);
> + i915_ttm_free_cached_io_st(obj);
> +
> + if (!new_man->use_tt)
> + obj->ttm.cached_io_st = new_st;
> +
> + return 0;
> +}
> +
> +struct ttm_device_funcs i915_ttm_bo_driver = {
> + .ttm_tt_create = i915_ttm_tt_create,
> + .ttm_tt_unpopulate = i915_ttm_tt_unpopulate,
> + .ttm_tt_destroy = i915_ttm_tt_destroy,
> + .eviction_valuable = i915_ttm_eviction_valuable,
> + .evict_flags = i915_ttm_evict_flags,
> + .move = i915_ttm_move,
> + .verify_access = NULL,
> + .swap_notify = i915_ttm_swap_notify,
> + .delete_mem_notify = i915_ttm_delete_mem_notify,
> +};
> +
> +static int i915_ttm_get_pages(struct drm_i915_gem_object *obj)
> +{
> + struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
> + struct ttm_operation_ctx ctx = {
> + .interruptible = true,
> + .no_wait_gpu = false,
> + };
> + struct sg_table *st;
> + int ret;
> +
> + /* Swap in. */
> + if (bo->ttm && (bo->ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
> + ret = ttm_tt_populate(bo->bdev, bo->ttm, &ctx);
> + if (ret)
> + return ret;
> + }
> +
> + /* Move to the requested placement. */
> + ret = ttm_bo_validate(bo, &i915_lmem0_placement, &ctx);
> + if (ret)
> + return ret == -ENOSPC ? -ENXIO : ret;
> +
> + /* Object either has a page vector or is an iomem object */
> + st = bo->ttm ? i915_ttm_tt_get_st(bo->ttm) : obj->ttm.cached_io_st;
> + if (IS_ERR(st))
> + return PTR_ERR(st);
> +
> + __i915_gem_object_set_pages(obj, st, i915_sg_dma_sizes(st->sgl));
> +
> + i915_ttm_adjust_lru(obj);
> +
> + return ret;
> +}
> +
> +static void i915_ttm_put_pages(struct drm_i915_gem_object *obj,
> + struct sg_table *st)
> +{
> + /*
> + * We're currently not called from a shrinker, so put_pages()
> + * typically means the object is about to destroyed, or called
> + * from move_notify(). So just avoid doing much for now.
> + * If the object is not destroyed next, The TTM eviction logic
> + * and shrinkers will move it out if needed.
> + */
> +
> + i915_ttm_adjust_lru(obj);
> +}
> +
> +static void i915_ttm_adjust_lru(struct drm_i915_gem_object *obj)
> +{
> + struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
> +
> + /*
> + * Don't manipulate the TTM LRUs while in TTM bo destruction.
> + * We're called through i915_ttm_delete_mem_notify().
> + */
> + if (!kref_read(&bo->kref))
> + return;
> +
> + /*
> + * Put on the correct LRU list depending on the MADV status
> + */
> + spin_lock(&bo->bdev->lru_lock);
> + if (obj->mm.madv != I915_MADV_WILLNEED) {
> + bo->priority = I915_TTM_PRIO_PURGE;
> + } else if (!i915_gem_object_has_pages(obj)) {
> + if (bo->priority < I915_TTM_PRIO_HAS_PAGES)
> + bo->priority = I915_TTM_PRIO_HAS_PAGES;
> + } else {
> + if (bo->priority > I915_TTM_PRIO_NO_PAGES)
> + bo->priority = I915_TTM_PRIO_NO_PAGES;
> + }
> +
> + ttm_bo_move_to_lru_tail(bo, &bo->mem, NULL);
> + spin_unlock(&bo->bdev->lru_lock);
> +}
> +
> +/*
> + * TTM-backed gem object destruction requires some clarification.
> + * Basically we have two possibilities here. We can either rely on the
> + * i915 delayed destruction and put the TTM object when the object
> + * is idle. This would be detected by TTM which would bypass the
> + * TTM delayed destroy handling. The other approach is to put the TTM
> + * object early and rely on the TTM destroyed handling, and then free
> + * the leftover parts of the GEM object once TTM's destroyed list handling is
> + * complete. For now, we rely on the latter for two reasons:
> + * a) TTM can evict an object even when it's on the delayed destroy list,
> + * which in theory allows for complete eviction.
> + * b) There is work going on in TTM to allow freeing an object even when
> + * it's not idle, and using the TTM destroyed list handling could help us
> + * benefit from that.
> + */
> +static void i915_ttm_delayed_free(struct drm_i915_gem_object *obj)
> +{
> + ttm_bo_put(i915_gem_to_ttm(obj));
> +}
> +
> +static const struct drm_i915_gem_object_ops i915_gem_ttm_obj_ops = {
> + .name = "i915_gem_object_ttm",
> + .flags = I915_GEM_OBJECT_HAS_IOMEM,
> +
> + .get_pages = i915_ttm_get_pages,
> + .put_pages = i915_ttm_put_pages,
> + .truncate = i915_ttm_purge,
> + .adjust_lru = i915_ttm_adjust_lru,
> + .delayed_free = i915_ttm_delayed_free,
> +};
> +
> +void i915_ttm_bo_destroy(struct ttm_buffer_object *bo)
> +{
> + struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
> +
> + i915_gem_object_release_memory_region(obj);
> + call_rcu(&obj->rcu, __i915_gem_free_object_rcu);
> +}
> +
> +/**
> + * __i915_gem_ttm_object_init - Initialize a ttm-backed i915 gem object
> + * @mem: The initial memory region for the object.
> + * @obj: The gem object.
> + * @size: Object size in bytes.
> + * @flags: gem object flags.
> + *
> + * Return: 0 on success, negative error code on failure.
> + */
> +int __i915_gem_ttm_object_init(struct intel_memory_region *mem,
> + struct drm_i915_gem_object *obj,
> + resource_size_t size,
> + unsigned int flags)
> +{
> + static struct lock_class_key lock_class;
> + struct drm_i915_private *i915 = mem->i915;
> + size_t alignment = 0;
> + int ret;
> +
> + /* Adjust alignment to GPU- and CPU huge page sizes. */
> +
> + if (mem->is_range_manager) {
> + if (size >= SZ_1G)
> + alignment = SZ_1G >> PAGE_SHIFT;
> + else if (size >= SZ_2M)
> + alignment = SZ_2M >> PAGE_SHIFT;
> + else if (size >= SZ_64K)
> + alignment = SZ_64K >> PAGE_SHIFT;
> + }
> +
> + drm_gem_private_object_init(&i915->drm, &obj->base, size);
> + i915_gem_object_init(obj, &i915_gem_ttm_obj_ops, &lock_class, flags);
> + i915_gem_object_init_memory_region(obj, mem);
> + i915_gem_object_make_unshrinkable(obj);
> + obj->read_domains = I915_GEM_DOMAIN_WC | I915_GEM_DOMAIN_GTT;
> + i915_gem_object_set_cache_coherency(obj, I915_CACHE_NONE);
> +
> + ret = ttm_bo_init(&i915->bdev, i915_gem_to_ttm(obj), size,
> + ttm_bo_type_kernel, &i915_sys_placement, alignment,
> + true, NULL, NULL, i915_ttm_bo_destroy);
Move this further up, or add some onion?
Reviewed-by: Matthew Auld <matthew.auld at intel.com>
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