[Intel-gfx] [PATCH v5 09/13] drm/i915/ttm: add tt shmem backend
Zeng, Oak
oak.zeng at intel.com
Tue Oct 5 18:33:18 UTC 2021
Thanks for explanation. This patch is Acked-by: Oak Zeng <Oak.Zeng at intel.com>
Regards,
Oak
> -----Original Message-----
> From: Auld, Matthew <matthew.auld at intel.com>
> Sent: October 5, 2021 1:07 PM
> To: Zeng, Oak <oak.zeng at intel.com>; Thomas Hellström
> <thomas.hellstrom at linux.intel.com>; intel-gfx at lists.freedesktop.org
> Cc: dri-devel at lists.freedesktop.org; Christian König
> <christian.koenig at amd.com>
> Subject: Re: [Intel-gfx] [PATCH v5 09/13] drm/i915/ttm: add tt shmem
> backend
>
> On 05/10/2021 15:23, Zeng, Oak wrote:
> >
> >
> > Regards,
> > Oak
> >
> >> -----Original Message-----
> >> From: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> >> Sent: October 5, 2021 9:48 AM
> >> To: Zeng, Oak <oak.zeng at intel.com>; Auld, Matthew
> >> <matthew.auld at intel.com>; intel-gfx at lists.freedesktop.org
> >> Cc: dri-devel at lists.freedesktop.org; Christian König
> >> <christian.koenig at amd.com>
> >> Subject: Re: [Intel-gfx] [PATCH v5 09/13] drm/i915/ttm: add tt shmem
> >> backend
> >>
> >>
> >> On 10/5/21 04:05, Zeng, Oak wrote:
> >>> Hi Matthew/Thomas,
> >>>
> >>> See one question inline
> >>>
> >>> Regards,
> >>> Oak
> >>>
> >>> -----Original Message-----
> >>> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of
> >> Matthew Auld
> >>> Sent: September 27, 2021 7:41 AM
> >>> To: intel-gfx at lists.freedesktop.org
> >>> Cc: dri-devel at lists.freedesktop.org; Thomas Hellström
> >> <thomas.hellstrom at linux.intel.com>; Christian König
> >> <christian.koenig at amd.com>
> >>> Subject: [Intel-gfx] [PATCH v5 09/13] drm/i915/ttm: add tt shmem
> backend
> >>>
> >>> For cached objects we can allocate our pages directly in shmem. This
> should
> >> make it possible(in a later patch) to utilise the existing i915-gem shrinker
> code
> >> for such objects. For now this is still disabled.
> >>>
> >>> v2(Thomas):
> >>> - Add optional try_to_writeback hook for objects. Importantly we need
> >>> to check if the object is even still shrinkable; in between us
> >>> dropping the shrinker LRU lock and acquiring the object lock it could for
> >>> example have been moved. Also we need to differentiate between
> >>> "lazy" shrinking and the immediate writeback mode. Also later we
> need
> >> to
> >>> handle objects which don't even have mm.pages, so bundling this into
> >>> put_pages() would require somehow handling that edge case, hence
> >>> just letting the ttm backend handle everything in try_to_writeback
> >>> doesn't seem too bad.
> >>> v3(Thomas):
> >>> - Likely a bad idea to touch the object from the unpopulate hook,
> >>> since it's not possible to hold a reference, without also creating
> >>> circular dependency, so likely this is too fragile. For now just
> >>> ensure we at least mark the pages as dirty/accessed when called from
> the
> >>> shrinker on WILLNEED objects.
> >>> - s/try_to_writeback/shrinker_release_pages, since this can do more
> >>> than just writeback.
> >>> - Get rid of do_backup boolean and just set the SWAPPED flag prior to
> >>> calling unpopulate.
> >>> - Keep shmem_tt as lowest priority for the TTM LRU bo_swapout walk,
> >> since
> >>> these just get skipped anyway. We can try to come up with something
> >>> better later.
> >>>
> >>> Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> >>> Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> >>> Cc: Christian König <christian.koenig at amd.com>
> >>> ---
> >>> drivers/gpu/drm/i915/gem/i915_gem_object.h | 8 +
> >>> .../gpu/drm/i915/gem/i915_gem_object_types.h | 2 +
> >>> drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 14 +-
> >>> drivers/gpu/drm/i915/gem/i915_gem_shrinker.c | 17 +-
> >>> drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 240
> ++++++++++++++++-
> >> -
> >>> 5 files changed, 245 insertions(+), 36 deletions(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> >> b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> >>> index 3043fcbd31bd..1c9a1d8d3434 100644
> >>> --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> >>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> >>> @@ -601,6 +601,14 @@ int i915_gem_object_wait_migration(struct
> >> drm_i915_gem_object *obj, bool
> >> i915_gem_object_placement_possible(struct drm_i915_gem_object *obj,
> >>> enum intel_memory_type type);
> >>>
> >>> +struct sg_table *shmem_alloc_st(struct drm_i915_private *i915,
> >>> + size_t size, struct intel_memory_region *mr,
> >>> + struct address_space *mapping,
> >>> + unsigned int max_segment);
> >>> +void shmem_free_st(struct sg_table *st, struct address_space
> *mapping,
> >>> + bool dirty, bool backup);
> >>> +void __shmem_writeback(size_t size, struct address_space *mapping);
> >>> +
> >>> #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 fa2ba9e2a4d0..f0fb17be2f7a 100644
> >>> --- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
> >>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
> >>> @@ -56,6 +56,8 @@ struct drm_i915_gem_object_ops {
> >>> struct sg_table *pages);
> >>> void (*truncate)(struct drm_i915_gem_object *obj);
> >>> void (*writeback)(struct drm_i915_gem_object *obj);
> >>> + int (*shrinker_release_pages)(struct drm_i915_gem_object *obj,
> >>> + bool should_writeback);
> >>>
> >>> int (*pread)(struct drm_i915_gem_object *obj,
> >>> const struct drm_i915_gem_pread *arg); diff --git
> >> a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> >> b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> >>> index 36b711ae9e28..19e55cc29a15 100644
> >>> --- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> >>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> >>> @@ -25,8 +25,8 @@ static void check_release_pagevec(struct pagevec
> >> *pvec)
> >>> cond_resched();
> >>> }
> >>>
> >>> -static void shmem_free_st(struct sg_table *st, struct address_space
> >> *mapping,
> >>> - bool dirty, bool backup)
> >>> +void shmem_free_st(struct sg_table *st, struct address_space
> *mapping,
> >>> + bool dirty, bool backup)
> >>> {
> >>> struct sgt_iter sgt_iter;
> >>> struct pagevec pvec;
> >>> @@ -52,10 +52,10 @@ static void shmem_free_st(struct sg_table *st,
> struct
> >> address_space *mapping,
> >>> kfree(st);
> >>> }
> >>>
> >>> -static struct sg_table *shmem_alloc_st(struct drm_i915_private *i915,
> >>> - size_t size, struct intel_memory_region
> >> *mr,
> >>> - struct address_space *mapping,
> >>> - unsigned int max_segment)
> >>> +struct sg_table *shmem_alloc_st(struct drm_i915_private *i915,
> >>> + size_t size, struct intel_memory_region *mr,
> >>> + struct address_space *mapping,
> >>> + unsigned int max_segment)
> >>> {
> >>> const unsigned long page_count = size / PAGE_SIZE;
> >>> unsigned long i;
> >>> @@ -300,7 +300,7 @@ shmem_truncate(struct drm_i915_gem_object
> *obj)
> >>> obj->mm.pages = ERR_PTR(-EFAULT);
> >>> }
> >>>
> >>> -static void __shmem_writeback(size_t size, struct address_space
> >> *mapping)
> >>> +void __shmem_writeback(size_t size, struct address_space *mapping)
> >>> {
> >>> struct writeback_control wbc = {
> >>> .sync_mode = WB_SYNC_NONE,
> >>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
> >> b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
> >>> index e382b7f2353b..cc80bd23d323 100644
> >>> --- a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
> >>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
> >>> @@ -56,19 +56,24 @@ static bool unsafe_drop_pages(struct
> >> drm_i915_gem_object *obj,
> >>> return false;
> >>> }
> >>>
> >>> -static void try_to_writeback(struct drm_i915_gem_object *obj,
> >>> - unsigned int flags)
> >>> +static int try_to_writeback(struct drm_i915_gem_object *obj, unsigned
> >>> +int flags)
> >>> {
> >>> + if (obj->ops->shrinker_release_pages)
> >>> + return obj->ops->shrinker_release_pages(obj,
> >>> + flags &
> >> I915_SHRINK_WRITEBACK);
> >>> +
> >>> switch (obj->mm.madv) {
> >>> case I915_MADV_DONTNEED:
> >>> i915_gem_object_truncate(obj);
> >>> - return;
> >>> + return 0;
> >>> case __I915_MADV_PURGED:
> >>> - return;
> >>> + return 0;
> >>> }
> >>>
> >>> if (flags & I915_SHRINK_WRITEBACK)
> >>> i915_gem_object_writeback(obj);
> >>> +
> >>> + return 0;
> >>> }
> >>>
> >>> /**
> >>> @@ -222,8 +227,8 @@ i915_gem_shrink(struct i915_gem_ww_ctx *ww,
> >>> }
> >>>
> >>> if (!__i915_gem_object_put_pages(obj)) {
> >>> - try_to_writeback(obj, shrink);
> >>> - count += obj->base.size >>
> >> PAGE_SHIFT;
> >>> + if (!try_to_writeback(obj, shrink))
> >>> + count += obj->base.size >>
> >> PAGE_SHIFT;
> >>> }
> >>> if (!ww)
> >>> i915_gem_object_unlock(obj);
> >>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> >> b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> >>> index a77e90f300fe..c7402995a8f9 100644
> >>> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> >>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> >>> @@ -35,6 +35,8 @@
> >>> * @ttm: The base TTM page vector.
> >>> * @dev: The struct device used for dma mapping and unmapping.
> >>> * @cached_st: The cached scatter-gather table.
> >>> + * @is_shmem: Set if using shmem.
> >>> + * @filp: The shmem file, if using shmem backend.
> >>> *
> >>> * Note that DMA may be going on right up to the point where the page-
> >>> * vector is unpopulated in delayed destroy. Hence keep the @@ -46,6
> >> +48,9 @@ struct i915_ttm_tt {
> >>> struct ttm_tt ttm;
> >>> struct device *dev;
> >>> struct sg_table *cached_st;
> >>> +
> >>> + bool is_shmem;
> >>> + struct file *filp;
> >>> };
> >>>
> >>> static const struct ttm_place sys_placement_flags = { @@ -179,12
> +184,90
> >> @@ i915_ttm_placement_from_obj(const struct drm_i915_gem_object
> *obj,
> >>> placement->busy_placement = busy;
> >>> }
> >>>
> >>> +static int i915_ttm_tt_shmem_populate(struct ttm_device *bdev,
> >>> + struct ttm_tt *ttm,
> >>> + struct ttm_operation_ctx *ctx) {
> >>> + struct drm_i915_private *i915 = container_of(bdev, typeof(*i915),
> >> bdev);
> >>> + struct intel_memory_region *mr = i915-
> >>> mm.regions[INTEL_MEMORY_SYSTEM];
> >>> + struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt),
> >> ttm);
> >>> + const unsigned int max_segment = i915_sg_segment_size();
> >>> + const size_t size = ttm->num_pages << PAGE_SHIFT;
> >>> + struct file *filp = i915_tt->filp;
> >>> + struct sgt_iter sgt_iter;
> >>> + struct sg_table *st;
> >>> + struct page *page;
> >>> + unsigned long i;
> >>> + int err;
> >>> +
> >>> + if (!filp) {
> >>> + struct address_space *mapping;
> >>> + gfp_t mask;
> >>> +
> >>> + filp = shmem_file_setup("i915-shmem-tt", size,
> >> VM_NORESERVE);
> >>> + if (IS_ERR(filp))
> >>> + return PTR_ERR(filp);
> >>> +
> >>> + mask = GFP_HIGHUSER | __GFP_RECLAIMABLE;
> >>> +
> >>> + mapping = filp->f_mapping;
> >>> + mapping_set_gfp_mask(mapping, mask);
> >>> + GEM_BUG_ON(!(mapping_gfp_mask(mapping) &
> >> __GFP_RECLAIM));
> >>> +
> >>> + i915_tt->filp = filp;
> >>> + }
> >>> +
> >>> + st = shmem_alloc_st(i915, size, mr, filp->f_mapping, max_segment);
> >>> + if (IS_ERR(st))
> >>> + return PTR_ERR(st);
> >>> +
> >>> + err = dma_map_sg_attrs(i915_tt->dev,
> >>> + st->sgl, st->nents,
> >>> + PCI_DMA_BIDIRECTIONAL,
> >>> + DMA_ATTR_SKIP_CPU_SYNC |
> >>> + DMA_ATTR_NO_KERNEL_MAPPING |
> >>> + DMA_ATTR_NO_WARN);
> >>> + if (err <= 0) {
> >>> + err = -EINVAL;
> >>> + goto err_free_st;
> >>> + }
> >>> +
> >>> + i = 0;
> >>> + for_each_sgt_page(page, sgt_iter, st)
> >>> + ttm->pages[i++] = page;
> >>> +
> >>> + if (ttm->page_flags & TTM_TT_FLAG_SWAPPED)
> >>> + ttm->page_flags &= ~TTM_TT_FLAG_SWAPPED;
> >>> +
> >>> + i915_tt->cached_st = st;
> >>> + return 0;
> >>> +
> >>> +err_free_st:
> >>> + shmem_free_st(st, filp->f_mapping, false, false);
> >>> + return err;
> >>> +}
> >>> +
> >>> +static void i915_ttm_tt_shmem_unpopulate(struct ttm_tt *ttm) {
> >>> + struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt),
> >> ttm);
> >>> + bool backup = ttm->page_flags & TTM_TT_FLAG_SWAPPED;
> >>> +
> >>> + dma_unmap_sg(i915_tt->dev, i915_tt->cached_st->sgl,
> >>> + i915_tt->cached_st->nents,
> >>> + PCI_DMA_BIDIRECTIONAL);
> >>> +
> >>> + shmem_free_st(fetch_and_zero(&i915_tt->cached_st),
> >>> + file_inode(i915_tt->filp)->i_mapping,
> >>> + backup, backup);
> >>>
> >>> Should we do something to undo the shmem_file_setup operation
> here?
> >> From its implementation it does take a reference counter of inode and
> >> allocate file:
> >> https://elixir.bootlin.com/linux/latest/source/mm/shmem.c#L4084
> >>>
> >>> Regards,
> >>> Oak
> >>
> >> Hi, Oak,
> >>
> >> That's done in i915_ttm_tt_destroy() afaict.
> >>
> >> /Thomas
> >
> > Do we know whether this tt is back by a shmem at create time? If yes, I
> think a better place to do the shmem_file_setup is in i915_ttm_tt_create -
> this pairs with the fput in i915_ttm_tt_destroy. If we don't have such
> information at tt create time, I agree with the current approach.
>
> IIRC the tt_create is called even if the object will mostly likely just
> end up being placed in VRAM, so calling shmem_file_setup in there seemed
> potentially wasteful, since the shmem file might never even be needed.
> Hence keeping it in populate instead.
>
> >
> > Regards,
> > Oak
> >
> >>
> >>
> >>
> >>>
> >>> +}
> >>> +
> >>> 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->resource->mem_type);
> >>> struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
> >>> + enum ttm_caching caching = i915_ttm_select_tt_caching(obj);
> >>> struct i915_ttm_tt *i915_tt;
> >>> int ret;
> >>>
> >>> @@ -196,36 +279,62 @@ static struct ttm_tt *i915_ttm_tt_create(struct
> >> ttm_buffer_object *bo,
> >>> man->use_tt)
> >>> page_flags |= TTM_TT_FLAG_ZERO_ALLOC;
> >>>
> >>> - ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags,
> >>> - i915_ttm_select_tt_caching(obj));
> >>> - if (ret) {
> >>> - kfree(i915_tt);
> >>> - return NULL;
> >>> + if (i915_gem_object_is_shrinkable(obj) && caching == ttm_cached) {
> >>> + page_flags |= TTM_TT_FLAG_EXTERNAL |
> >>> + TTM_TT_FLAG_EXTERNAL_MAPPABLE;
> >>> + i915_tt->is_shmem = true;
> >>> }
> >>>
> >>> + ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags, caching);
> >>> + if (ret)
> >>> + goto err_free;
> >>> +
> >>> i915_tt->dev = obj->base.dev->dev;
> >>>
> >>> return &i915_tt->ttm;
> >>> +
> >>> +err_free:
> >>> + kfree(i915_tt);
> >>> + return NULL;
> >>> +}
> >>> +
> >>> +static int i915_ttm_tt_populate(struct ttm_device *bdev,
> >>> + struct ttm_tt *ttm,
> >>> + struct ttm_operation_ctx *ctx)
> >>> +{
> >>> + struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt),
> >>> +ttm);
> >>> +
> >>> + if (i915_tt->is_shmem)
> >>> + return i915_ttm_tt_shmem_populate(bdev, ttm, ctx);
> >>> +
> >>> + return ttm_pool_alloc(&bdev->pool, ttm, ctx);
> >>> }
> >>>
> >>> 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;
> >>> + if (i915_tt->is_shmem) {
> >>> + i915_ttm_tt_shmem_unpopulate(ttm);
> >>> + } else {
> >>> + 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);
> >>> }
> >>> - 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);
> >>>
> >>> + if (i915_tt->filp)
> >>> + fput(i915_tt->filp);
> >>> +
> >>> ttm_tt_fini(ttm);
> >>> kfree(i915_tt);
> >>> }
> >>> @@ -235,6 +344,14 @@ static bool i915_ttm_eviction_valuable(struct
> >> ttm_buffer_object *bo, {
> >>> struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
> >>>
> >>> + /*
> >>> + * EXTERNAL objects should never be swapped out by TTM, instead
> >> we need
> >>> + * to handle that ourselves. TTM will already skip such objects for us,
> >>> + * but we would like to avoid grabbing locks for no good reason.
> >>> + */
> >>> + if (bo->ttm && bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL)
> >>> + return -EBUSY;
> >>> +
> >>> /* Will do for now. Our pinned objects are still on TTM's LRU lists */
> >>> return i915_gem_object_evictable(obj); } @@ -328,9 +445,11 @@
> >> static void i915_ttm_adjust_gem_after_move(struct
> drm_i915_gem_object
> >> *obj)
> >>> i915_gem_object_set_cache_coherency(obj, cache_level); }
> >>>
> >>> -static void i915_ttm_purge(struct drm_i915_gem_object *obj)
> >>> +static int __i915_ttm_purge(struct drm_i915_gem_object *obj)
> >>> {
> >>> struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
> >>> + struct i915_ttm_tt *i915_tt =
> >>> + container_of(bo->ttm, typeof(*i915_tt), ttm);
> >>> struct ttm_operation_ctx ctx = {
> >>> .interruptible = true,
> >>> .no_wait_gpu = false,
> >>> @@ -339,17 +458,79 @@ static void i915_ttm_purge(struct
> >> drm_i915_gem_object *obj)
> >>> int ret;
> >>>
> >>> if (obj->mm.madv == __I915_MADV_PURGED)
> >>> - return;
> >>> + return 0;
> >>>
> >>> - /* TTM's purge interface. Note that we might be reentering. */
> >>> ret = ttm_bo_validate(bo, &place, &ctx);
> >>> - if (!ret) {
> >>> - obj->write_domain = 0;
> >>> - obj->read_domains = 0;
> >>> - i915_ttm_adjust_gem_after_move(obj);
> >>> - i915_ttm_free_cached_io_st(obj);
> >>> - obj->mm.madv = __I915_MADV_PURGED;
> >>> + if (ret)
> >>> + return ret;
> >>> +
> >>> + if (bo->ttm && i915_tt->filp) {
> >>> + /*
> >>> + * The below fput(which eventually calls shmem_truncate)
> >> might
> >>> + * be delayed by worker, so when directly called to purge the
> >>> + * pages(like by the shrinker) we should try to be more
> >>> + * aggressive and release the pages immediately.
> >>> + */
> >>> + shmem_truncate_range(file_inode(i915_tt->filp),
> >>> + 0, (loff_t)-1);
> >>> + fput(fetch_and_zero(&i915_tt->filp));
> >>> + }
> >>> +
> >>> + obj->write_domain = 0;
> >>> + obj->read_domains = 0;
> >>> + i915_ttm_adjust_gem_after_move(obj);
> >>> + i915_ttm_free_cached_io_st(obj);
> >>> + obj->mm.madv = __I915_MADV_PURGED;
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static void i915_ttm_purge(struct drm_i915_gem_object *obj) {
> >>> + __i915_ttm_purge(obj);
> >>> +}
> >>> +
> >>> +static int i915_ttm_shrinker_release_pages(struct
> drm_i915_gem_object
> >> *obj,
> >>> + bool should_writeback)
> >>> +{
> >>> + struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
> >>> + struct i915_ttm_tt *i915_tt =
> >>> + container_of(bo->ttm, typeof(*i915_tt), ttm);
> >>> + struct ttm_operation_ctx ctx = {
> >>> + .interruptible = true,
> >>> + .no_wait_gpu = false,
> >>> + };
> >>> + struct ttm_placement place = {};
> >>> + int ret;
> >>> +
> >>> + if (!bo->ttm || bo->resource->mem_type != TTM_PL_SYSTEM)
> >>> + return 0;
> >>> +
> >>> + GEM_BUG_ON(!i915_tt->is_shmem);
> >>> +
> >>> + if (!i915_tt->filp)
> >>> + return 0;
> >>> +
> >>> + switch (obj->mm.madv) {
> >>> + case I915_MADV_DONTNEED:
> >>> + return __i915_ttm_purge(obj);
> >>> + case __I915_MADV_PURGED:
> >>> + return 0;
> >>> + }
> >>> +
> >>> + if (bo->ttm->page_flags & TTM_TT_FLAG_SWAPPED)
> >>> + return 0;
> >>> +
> >>> + bo->ttm->page_flags |= TTM_TT_FLAG_SWAPPED;
> >>> + ret = ttm_bo_validate(bo, &place, &ctx);
> >>> + if (ret) {
> >>> + bo->ttm->page_flags &= ~TTM_TT_FLAG_SWAPPED;
> >>> + return ret;
> >>> }
> >>> +
> >>> + if (should_writeback)
> >>> + __shmem_writeback(obj->base.size, i915_tt->filp-
> >>> f_mapping);
> >>> +
> >>> + return 0;
> >>> }
> >>>
> >>> static void i915_ttm_swap_notify(struct ttm_buffer_object *bo) @@ -
> >> 618,6 +799,7 @@ static unsigned long i915_ttm_io_mem_pfn(struct
> >> ttm_buffer_object *bo,
> >>>
> >>> static struct ttm_device_funcs i915_ttm_bo_driver = {
> >>> .ttm_tt_create = i915_ttm_tt_create,
> >>> + .ttm_tt_populate = i915_ttm_tt_populate,
> >>> .ttm_tt_unpopulate = i915_ttm_tt_unpopulate,
> >>> .ttm_tt_destroy = i915_ttm_tt_destroy,
> >>> .eviction_valuable = i915_ttm_eviction_valuable, @@ -685,12 +867,17
> >> @@ static int __i915_ttm_get_pages(struct drm_i915_gem_object *obj,
> >>> }
> >>>
> >>> if (!i915_gem_object_has_pages(obj)) {
> >>> + struct i915_ttm_tt *i915_tt =
> >>> + container_of(bo->ttm, typeof(*i915_tt), ttm);
> >>> +
> >>> /* 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));
> >>> + if (!bo->ttm || !i915_tt->is_shmem)
> >>> + i915_gem_object_make_unshrinkable(obj);
> >>> }
> >>>
> >>> return ret;
> >>> @@ -770,6 +957,8 @@ static void i915_ttm_put_pages(struct
> >> drm_i915_gem_object *obj, static void i915_ttm_adjust_lru(struct
> >> drm_i915_gem_object *obj) {
> >>> struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
> >>> + struct i915_ttm_tt *i915_tt =
> >>> + container_of(bo->ttm, typeof(*i915_tt), ttm);
> >>>
> >>> /*
> >>> * Don't manipulate the TTM LRUs while in TTM bo destruction.
> >>> @@ -782,7 +971,10 @@ static void i915_ttm_adjust_lru(struct
> >> drm_i915_gem_object *obj)
> >>> * Put on the correct LRU list depending on the MADV status
> >>> */
> >>> spin_lock(&bo->bdev->lru_lock);
> >>> - if (obj->mm.madv != I915_MADV_WILLNEED) {
> >>> + if (bo->ttm && i915_tt->filp) {
> >>> + /* Try to keep shmem_tt from being considered for shrinking.
> >> */
> >>> + bo->priority = TTM_MAX_BO_PRIORITY - 1;
> >>> + } else 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) @@ -887,9
> >> +1079,12 @@ static const struct drm_i915_gem_object_ops
> >> i915_gem_ttm_obj_ops = {
> >>> .get_pages = i915_ttm_get_pages,
> >>> .put_pages = i915_ttm_put_pages,
> >>> .truncate = i915_ttm_purge,
> >>> + .shrinker_release_pages = i915_ttm_shrinker_release_pages,
> >>> +
> >>> .adjust_lru = i915_ttm_adjust_lru,
> >>> .delayed_free = i915_ttm_delayed_free,
> >>> .migrate = i915_ttm_migrate,
> >>> +
> >>> .mmap_offset = i915_ttm_mmap_offset,
> >>> .mmap_ops = &vm_ops_ttm,
> >>> };
> >>> @@ -937,7 +1132,6 @@ int __i915_gem_ttm_object_init(struct
> >> intel_memory_region *mem,
> >>> 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);
> >>> INIT_RADIX_TREE(&obj->ttm.get_io_page.radix, GFP_KERNEL |
> >> __GFP_NOWARN);
> >>> mutex_init(&obj->ttm.get_io_page.lock);
> >>> bo_type = (obj->flags & I915_BO_ALLOC_USER) ?
> >> ttm_bo_type_device :
> >>> --
> >>> 2.26.3
> >>>
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