[PATCH v4 1/2] drm/ttm: Move swapped objects off the manager's LRU list
Christian König
christian.koenig at amd.com
Wed Sep 4 08:50:54 UTC 2024
Am 04.09.24 um 09:08 schrieb Thomas Hellström:
> Resources of swapped objects remains on the TTM_PL_SYSTEM manager's
> LRU list, which is bad for the LRU walk efficiency.
>
> Rename the device-wide "pinned" list to "unevictable" and move
> also resources of swapped-out objects to that list.
>
> An alternative would be to create an "UNEVICTABLE" priority to
> be able to keep the pinned- and swapped objects on their
> respective manager's LRU without affecting the LRU walk efficiency.
>
> v2:
> - Remove a bogus WARN_ON (Christian König)
> - Update ttm_resource_[add|del] bulk move (Christian König)
> - Fix TTM KUNIT tests (Intel CI)
> v3:
> - Check for non-NULL bo->resource in ttm_bo_populate().
> v4:
> - Don't move to LRU tail during swapout until the resource
> is properly swapped or there was a swapout failure.
> (Intel Ci)
> - Add a newline after checkpatch check.
>
> Cc: Christian König <christian.koenig at amd.com>
> Cc: Matthew Brost <matthew.brost at intel.com>
> Cc: <dri-devel at lists.freedesktop.org>
> Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
I really wonder if having a SWAPPED wouldn't be cleaner in the long run.
Anyway, that seems to work for now. So patch is Reviewed-by: Christian
König <christian.koenig at amd.com>.
Regards,
Christian.
> ---
> drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 2 +-
> drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c | 2 +-
> drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c | 4 +-
> drivers/gpu/drm/ttm/tests/ttm_bo_test.c | 4 +-
> drivers/gpu/drm/ttm/tests/ttm_resource_test.c | 6 +-
> drivers/gpu/drm/ttm/ttm_bo.c | 59 ++++++++++++++++++-
> drivers/gpu/drm/ttm/ttm_bo_util.c | 6 +-
> drivers/gpu/drm/ttm/ttm_bo_vm.c | 2 +-
> drivers/gpu/drm/ttm/ttm_device.c | 4 +-
> drivers/gpu/drm/ttm/ttm_resource.c | 15 +++--
> drivers/gpu/drm/ttm/ttm_tt.c | 3 +
> drivers/gpu/drm/xe/xe_bo.c | 4 +-
> include/drm/ttm/ttm_bo.h | 2 +
> include/drm/ttm/ttm_device.h | 5 +-
> include/drm/ttm/ttm_tt.h | 5 ++
> 15 files changed, 96 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> index 5c72462d1f57..7de284766f82 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> @@ -808,7 +808,7 @@ static int __i915_ttm_get_pages(struct drm_i915_gem_object *obj,
> }
>
> if (bo->ttm && !ttm_tt_is_populated(bo->ttm)) {
> - ret = ttm_tt_populate(bo->bdev, bo->ttm, &ctx);
> + ret = ttm_bo_populate(bo, &ctx);
> if (ret)
> return ret;
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
> index 03b00a03a634..041dab543b78 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
> @@ -624,7 +624,7 @@ int i915_ttm_move(struct ttm_buffer_object *bo, bool evict,
>
> /* Populate ttm with pages if needed. Typically system memory. */
> if (ttm && (dst_man->use_tt || (ttm->page_flags & TTM_TT_FLAG_SWAPPED))) {
> - ret = ttm_tt_populate(bo->bdev, ttm, ctx);
> + ret = ttm_bo_populate(bo, ctx);
> if (ret)
> return ret;
> }
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
> index ad649523d5e0..61596cecce4d 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
> @@ -90,7 +90,7 @@ static int i915_ttm_backup(struct i915_gem_apply_to_region *apply,
> goto out_no_lock;
>
> backup_bo = i915_gem_to_ttm(backup);
> - err = ttm_tt_populate(backup_bo->bdev, backup_bo->ttm, &ctx);
> + err = ttm_bo_populate(backup_bo, &ctx);
> if (err)
> goto out_no_populate;
>
> @@ -189,7 +189,7 @@ static int i915_ttm_restore(struct i915_gem_apply_to_region *apply,
> if (!backup_bo->resource)
> err = ttm_bo_validate(backup_bo, i915_ttm_sys_placement(), &ctx);
> if (!err)
> - err = ttm_tt_populate(backup_bo->bdev, backup_bo->ttm, &ctx);
> + err = ttm_bo_populate(backup_bo, &ctx);
> if (!err) {
> err = i915_gem_obj_copy_ttm(obj, backup, pm_apply->allow_gpu,
> false);
> diff --git a/drivers/gpu/drm/ttm/tests/ttm_bo_test.c b/drivers/gpu/drm/ttm/tests/ttm_bo_test.c
> index f0a7eb62116c..3139fd9128d8 100644
> --- a/drivers/gpu/drm/ttm/tests/ttm_bo_test.c
> +++ b/drivers/gpu/drm/ttm/tests/ttm_bo_test.c
> @@ -308,11 +308,11 @@ static void ttm_bo_unreserve_pinned(struct kunit *test)
> err = ttm_resource_alloc(bo, place, &res2);
> KUNIT_ASSERT_EQ(test, err, 0);
> KUNIT_ASSERT_EQ(test,
> - list_is_last(&res2->lru.link, &priv->ttm_dev->pinned), 1);
> + list_is_last(&res2->lru.link, &priv->ttm_dev->unevictable), 1);
>
> ttm_bo_unreserve(bo);
> KUNIT_ASSERT_EQ(test,
> - list_is_last(&res1->lru.link, &priv->ttm_dev->pinned), 1);
> + list_is_last(&res1->lru.link, &priv->ttm_dev->unevictable), 1);
>
> ttm_resource_free(bo, &res1);
> ttm_resource_free(bo, &res2);
> diff --git a/drivers/gpu/drm/ttm/tests/ttm_resource_test.c b/drivers/gpu/drm/ttm/tests/ttm_resource_test.c
> index 22260e7aea58..a9f4b81921c3 100644
> --- a/drivers/gpu/drm/ttm/tests/ttm_resource_test.c
> +++ b/drivers/gpu/drm/ttm/tests/ttm_resource_test.c
> @@ -164,18 +164,18 @@ static void ttm_resource_init_pinned(struct kunit *test)
>
> res = kunit_kzalloc(test, sizeof(*res), GFP_KERNEL);
> KUNIT_ASSERT_NOT_NULL(test, res);
> - KUNIT_ASSERT_TRUE(test, list_empty(&bo->bdev->pinned));
> + KUNIT_ASSERT_TRUE(test, list_empty(&bo->bdev->unevictable));
>
> dma_resv_lock(bo->base.resv, NULL);
> ttm_bo_pin(bo);
> ttm_resource_init(bo, place, res);
> - KUNIT_ASSERT_TRUE(test, list_is_singular(&bo->bdev->pinned));
> + KUNIT_ASSERT_TRUE(test, list_is_singular(&bo->bdev->unevictable));
>
> ttm_bo_unpin(bo);
> ttm_resource_fini(man, res);
> dma_resv_unlock(bo->base.resv);
>
> - KUNIT_ASSERT_TRUE(test, list_empty(&bo->bdev->pinned));
> + KUNIT_ASSERT_TRUE(test, list_empty(&bo->bdev->unevictable));
> }
>
> static void ttm_resource_fini_basic(struct kunit *test)
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 320592435252..875b024913a0 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -139,7 +139,7 @@ static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo,
> goto out_err;
>
> if (mem->mem_type != TTM_PL_SYSTEM) {
> - ret = ttm_tt_populate(bo->bdev, bo->ttm, ctx);
> + ret = ttm_bo_populate(bo, ctx);
> if (ret)
> goto out_err;
> }
> @@ -1128,9 +1128,20 @@ ttm_bo_swapout_cb(struct ttm_lru_walk *walk, struct ttm_buffer_object *bo)
> if (bo->bdev->funcs->swap_notify)
> bo->bdev->funcs->swap_notify(bo);
>
> - if (ttm_tt_is_populated(bo->ttm))
> + if (ttm_tt_is_populated(bo->ttm)) {
> + spin_lock(&bo->bdev->lru_lock);
> + ttm_resource_del_bulk_move(bo->resource, bo);
> + spin_unlock(&bo->bdev->lru_lock);
> +
> ret = ttm_tt_swapout(bo->bdev, bo->ttm, swapout_walk->gfp_flags);
>
> + spin_lock(&bo->bdev->lru_lock);
> + if (ret)
> + ttm_resource_add_bulk_move(bo->resource, bo);
> + ttm_resource_move_to_lru_tail(bo->resource);
> + spin_unlock(&bo->bdev->lru_lock);
> + }
> +
> out:
> /* Consider -ENOMEM and -ENOSPC non-fatal. */
> if (ret == -ENOMEM || ret == -ENOSPC)
> @@ -1180,3 +1191,47 @@ void ttm_bo_tt_destroy(struct ttm_buffer_object *bo)
> ttm_tt_destroy(bo->bdev, bo->ttm);
> bo->ttm = NULL;
> }
> +
> +/**
> + * ttm_bo_populate() - Ensure that a buffer object has backing pages
> + * @bo: The buffer object
> + * @ctx: The ttm_operation_ctx governing the operation.
> + *
> + * For buffer objects in a memory type whose manager uses
> + * struct ttm_tt for backing pages, ensure those backing pages
> + * are present and with valid content. The bo's resource is also
> + * placed on the correct LRU list if it was previously swapped
> + * out.
> + *
> + * Return: 0 if successful, negative error code on failure.
> + * Note: May return -EINTR or -ERESTARTSYS if @ctx::interruptible
> + * is set to true.
> + */
> +int ttm_bo_populate(struct ttm_buffer_object *bo,
> + struct ttm_operation_ctx *ctx)
> +{
> + struct ttm_tt *tt = bo->ttm;
> + bool swapped;
> + int ret;
> +
> + dma_resv_assert_held(bo->base.resv);
> +
> + if (!tt)
> + return 0;
> +
> + swapped = ttm_tt_is_swapped(tt);
> + ret = ttm_tt_populate(bo->bdev, tt, ctx);
> + if (ret)
> + return ret;
> +
> + if (swapped && !ttm_tt_is_swapped(tt) && !bo->pin_count &&
> + bo->resource) {
> + spin_lock(&bo->bdev->lru_lock);
> + ttm_resource_add_bulk_move(bo->resource, bo);
> + ttm_resource_move_to_lru_tail(bo->resource);
> + spin_unlock(&bo->bdev->lru_lock);
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(ttm_bo_populate);
> diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
> index 3c07f4712d5c..d939925efa81 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> @@ -163,7 +163,7 @@ int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
> src_man = ttm_manager_type(bdev, src_mem->mem_type);
> if (ttm && ((ttm->page_flags & TTM_TT_FLAG_SWAPPED) ||
> dst_man->use_tt)) {
> - ret = ttm_tt_populate(bdev, ttm, ctx);
> + ret = ttm_bo_populate(bo, ctx);
> if (ret)
> return ret;
> }
> @@ -350,7 +350,7 @@ static int ttm_bo_kmap_ttm(struct ttm_buffer_object *bo,
>
> BUG_ON(!ttm);
>
> - ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
> + ret = ttm_bo_populate(bo, &ctx);
> if (ret)
> return ret;
>
> @@ -507,7 +507,7 @@ int ttm_bo_vmap(struct ttm_buffer_object *bo, struct iosys_map *map)
> pgprot_t prot;
> void *vaddr;
>
> - ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
> + ret = ttm_bo_populate(bo, &ctx);
> if (ret)
> return ret;
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
> index 4212b8c91dd4..2c699ed1963a 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
> @@ -224,7 +224,7 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,
> };
>
> ttm = bo->ttm;
> - err = ttm_tt_populate(bdev, bo->ttm, &ctx);
> + err = ttm_bo_populate(bo, &ctx);
> if (err) {
> if (err == -EINTR || err == -ERESTARTSYS ||
> err == -EAGAIN)
> diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c
> index e7cc4954c1bc..02e797fd1891 100644
> --- a/drivers/gpu/drm/ttm/ttm_device.c
> +++ b/drivers/gpu/drm/ttm/ttm_device.c
> @@ -216,7 +216,7 @@ int ttm_device_init(struct ttm_device *bdev, const struct ttm_device_funcs *func
>
> bdev->vma_manager = vma_manager;
> spin_lock_init(&bdev->lru_lock);
> - INIT_LIST_HEAD(&bdev->pinned);
> + INIT_LIST_HEAD(&bdev->unevictable);
> bdev->dev_mapping = mapping;
> mutex_lock(&ttm_global_mutex);
> list_add_tail(&bdev->device_list, &glob->device_list);
> @@ -283,7 +283,7 @@ void ttm_device_clear_dma_mappings(struct ttm_device *bdev)
> struct ttm_resource_manager *man;
> unsigned int i, j;
>
> - ttm_device_clear_lru_dma_mappings(bdev, &bdev->pinned);
> + ttm_device_clear_lru_dma_mappings(bdev, &bdev->unevictable);
>
> for (i = TTM_PL_SYSTEM; i < TTM_NUM_MEM_TYPES; ++i) {
> man = ttm_manager_type(bdev, i);
> diff --git a/drivers/gpu/drm/ttm/ttm_resource.c b/drivers/gpu/drm/ttm/ttm_resource.c
> index 6d764ba88aab..93b44043b428 100644
> --- a/drivers/gpu/drm/ttm/ttm_resource.c
> +++ b/drivers/gpu/drm/ttm/ttm_resource.c
> @@ -30,6 +30,7 @@
> #include <drm/ttm/ttm_bo.h>
> #include <drm/ttm/ttm_placement.h>
> #include <drm/ttm/ttm_resource.h>
> +#include <drm/ttm/ttm_tt.h>
>
> #include <drm/drm_util.h>
>
> @@ -239,7 +240,8 @@ static void ttm_lru_bulk_move_del(struct ttm_lru_bulk_move *bulk,
> void ttm_resource_add_bulk_move(struct ttm_resource *res,
> struct ttm_buffer_object *bo)
> {
> - if (bo->bulk_move && !bo->pin_count)
> + if (bo->bulk_move && !bo->pin_count &&
> + (!bo->ttm || !ttm_tt_is_swapped(bo->ttm)))
> ttm_lru_bulk_move_add(bo->bulk_move, res);
> }
>
> @@ -247,7 +249,8 @@ void ttm_resource_add_bulk_move(struct ttm_resource *res,
> void ttm_resource_del_bulk_move(struct ttm_resource *res,
> struct ttm_buffer_object *bo)
> {
> - if (bo->bulk_move && !bo->pin_count)
> + if (bo->bulk_move && !bo->pin_count &&
> + (!bo->ttm || !ttm_tt_is_swapped(bo->ttm)))
> ttm_lru_bulk_move_del(bo->bulk_move, res);
> }
>
> @@ -259,8 +262,8 @@ void ttm_resource_move_to_lru_tail(struct ttm_resource *res)
>
> lockdep_assert_held(&bo->bdev->lru_lock);
>
> - if (bo->pin_count) {
> - list_move_tail(&res->lru.link, &bdev->pinned);
> + if (bo->pin_count || (bo->ttm && ttm_tt_is_swapped(bo->ttm))) {
> + list_move_tail(&res->lru.link, &bdev->unevictable);
>
> } else if (bo->bulk_move) {
> struct ttm_lru_bulk_move_pos *pos =
> @@ -301,8 +304,8 @@ void ttm_resource_init(struct ttm_buffer_object *bo,
>
> man = ttm_manager_type(bo->bdev, place->mem_type);
> spin_lock(&bo->bdev->lru_lock);
> - if (bo->pin_count)
> - list_add_tail(&res->lru.link, &bo->bdev->pinned);
> + if (bo->pin_count || (bo->ttm && ttm_tt_is_swapped(bo->ttm)))
> + list_add_tail(&res->lru.link, &bo->bdev->unevictable);
> else
> list_add_tail(&res->lru.link, &man->lru[bo->priority]);
> man->usage += res->size;
> diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
> index 4b51b9023126..3baf215eca23 100644
> --- a/drivers/gpu/drm/ttm/ttm_tt.c
> +++ b/drivers/gpu/drm/ttm/ttm_tt.c
> @@ -367,7 +367,10 @@ int ttm_tt_populate(struct ttm_device *bdev,
> }
> return ret;
> }
> +
> +#if IS_ENABLED(CONFIG_DRM_TTM_KUNIT_TEST)
> EXPORT_SYMBOL(ttm_tt_populate);
> +#endif
>
> void ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm)
> {
> diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
> index a8e4d46d9123..f34daae2cf2b 100644
> --- a/drivers/gpu/drm/xe/xe_bo.c
> +++ b/drivers/gpu/drm/xe/xe_bo.c
> @@ -892,7 +892,7 @@ int xe_bo_evict_pinned(struct xe_bo *bo)
> }
> }
>
> - ret = ttm_tt_populate(bo->ttm.bdev, bo->ttm.ttm, &ctx);
> + ret = ttm_bo_populate(&bo->ttm, &ctx);
> if (ret)
> goto err_res_free;
>
> @@ -945,7 +945,7 @@ int xe_bo_restore_pinned(struct xe_bo *bo)
> if (ret)
> return ret;
>
> - ret = ttm_tt_populate(bo->ttm.bdev, bo->ttm.ttm, &ctx);
> + ret = ttm_bo_populate(&bo->ttm, &ctx);
> if (ret)
> goto err_res_free;
>
> diff --git a/include/drm/ttm/ttm_bo.h b/include/drm/ttm/ttm_bo.h
> index 7b56d1ca36d7..5804408815be 100644
> --- a/include/drm/ttm/ttm_bo.h
> +++ b/include/drm/ttm/ttm_bo.h
> @@ -462,5 +462,7 @@ int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo);
> pgprot_t ttm_io_prot(struct ttm_buffer_object *bo, struct ttm_resource *res,
> pgprot_t tmp);
> void ttm_bo_tt_destroy(struct ttm_buffer_object *bo);
> +int ttm_bo_populate(struct ttm_buffer_object *bo,
> + struct ttm_operation_ctx *ctx);
>
> #endif
> diff --git a/include/drm/ttm/ttm_device.h b/include/drm/ttm/ttm_device.h
> index c22f30535c84..438358f72716 100644
> --- a/include/drm/ttm/ttm_device.h
> +++ b/include/drm/ttm/ttm_device.h
> @@ -252,9 +252,10 @@ struct ttm_device {
> spinlock_t lru_lock;
>
> /**
> - * @pinned: Buffer objects which are pinned and so not on any LRU list.
> + * @unevictable Buffer objects which are pinned or swapped and as such
> + * not on an LRU list.
> */
> - struct list_head pinned;
> + struct list_head unevictable;
>
> /**
> * @dev_mapping: A pointer to the struct address_space for invalidating
> diff --git a/include/drm/ttm/ttm_tt.h b/include/drm/ttm/ttm_tt.h
> index 2b9d856ff388..991edafdb2dd 100644
> --- a/include/drm/ttm/ttm_tt.h
> +++ b/include/drm/ttm/ttm_tt.h
> @@ -129,6 +129,11 @@ static inline bool ttm_tt_is_populated(struct ttm_tt *tt)
> return tt->page_flags & TTM_TT_FLAG_PRIV_POPULATED;
> }
>
> +static inline bool ttm_tt_is_swapped(const struct ttm_tt *tt)
> +{
> + return tt->page_flags & TTM_TT_FLAG_SWAPPED;
> +}
> +
> /**
> * ttm_tt_create
> *
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