[Intel-gfx] [PATCH v5 09/13] drm/i915/ttm: add tt shmem backend
Zeng, Oak
oak.zeng at intel.com
Tue Oct 5 14:23:41 UTC 2021
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.
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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