@@ -248,10 +248,13 @@ static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo,
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);
+ enum ttm_caching caching;
struct i915_ttm_tt *i915_tt;
int ret;
+ if (!obj)
+ return NULL;
+
i915_tt = kzalloc(sizeof(*i915_tt), GFP_KERNEL);
if (!i915_tt)
return NULL;
@@ -260,6 +263,7 @@ static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo,
man->use_tt)
page_flags |= TTM_TT_FLAG_ZERO_ALLOC;
+ caching = i915_ttm_select_tt_caching(obj);
if (i915_gem_object_is_shrinkable(obj) && caching == ttm_cached) {
page_flags |= TTM_TT_FLAG_EXTERNAL |
TTM_TT_FLAG_EXTERNAL_MAPPABLE;
@@ -326,6 +330,9 @@ static bool i915_ttm_eviction_valuable(struct ttm_buffer_object *bo,
{
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
+ if (!obj)
+ return false;
+
/*
* EXTERNAL objects should never be swapped out by TTM, instead we need
* to handle that ourselves. TTM will already skip such objects for us,
@@ -552,8 +559,12 @@ i915_ttm_resource_get_st(struct drm_i915_gem_object *obj,
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);
+ int ret;
+ if (!obj)
+ return;
+
+ ret = i915_ttm_move_notify(bo);
GEM_WARN_ON(ret);
GEM_WARN_ON(obj->ttm.cached_io_rsgt);
if (!ret && obj->mm.madv != I915_MADV_WILLNEED)
@@ -575,17 +586,23 @@ static unsigned long i915_ttm_io_mem_pfn(struct ttm_buffer_object *bo,
unsigned long page_offset)
{
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
- unsigned long base = obj->mm.region->iomap.base - obj->mm.region->region.start;
struct scatterlist *sg;
+ unsigned long base;
unsigned int ofs;
+ GEM_BUG_ON(!obj);
GEM_WARN_ON(bo->ttm);
+ base = obj->mm.region->iomap.base - obj->mm.region->region.start;
sg = __i915_gem_object_get_sg(obj, &obj->ttm.get_io_page, page_offset, &ofs, true);
return ((base + sg_dma_address(sg)) >> PAGE_SHIFT) + ofs;
}
+/*
+ * All callbacks need to take care not to downcast a struct ttm_buffer_object
+ * without checking its subclass, since it might be a TTM ghost object.
+ */
static struct ttm_device_funcs i915_ttm_bo_driver = {
.ttm_tt_create = i915_ttm_tt_create,
.ttm_tt_populate = i915_ttm_tt_populate,
@@ -847,13 +864,16 @@ static void i915_ttm_delayed_free(struct drm_i915_gem_object *obj)
static vm_fault_t vm_fault_ttm(struct vm_fault *vmf)
{
struct vm_area_struct *area = vmf->vma;
- struct drm_i915_gem_object *obj =
- i915_ttm_to_gem(area->vm_private_data);
- struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
+ struct ttm_buffer_object *bo = area->vm_private_data;
struct drm_device *dev = bo->base.dev;
+ struct drm_i915_gem_object *obj;
vm_fault_t ret;
int idx;
+ obj = i915_ttm_to_gem(bo);
+ if (!obj)
+ return VM_FAULT_SIGBUS;
+
/* Sanity check that we allow writing into this object */
if (unlikely(i915_gem_object_is_readonly(obj) &&
area->vm_flags & VM_WRITE))
@@ -37,7 +37,7 @@ void i915_ttm_bo_destroy(struct ttm_buffer_object *bo);
static inline struct drm_i915_gem_object *
i915_ttm_to_gem(struct ttm_buffer_object *bo)
{
- if (GEM_WARN_ON(bo->destroy != i915_ttm_bo_destroy))
+ if (bo->destroy != i915_ttm_bo_destroy)
return NULL;
return container_of(bo, struct drm_i915_gem_object, __do_not_access);
@@ -3,6 +3,8 @@
* Copyright © 2021 Intel Corporation
*/
+#include <linux/dma-fence-array.h>
+
#include <drm/ttm/ttm_bo_driver.h>
#include "i915_drv.h"
@@ -41,6 +43,234 @@ void i915_ttm_migrate_set_failure_modes(bool gpu_migration,
}
#endif
+/**
+ * DOC: Set of utilities to dynamically collect dependencies and
+ * eventually coalesce them into a single fence which is fed into
+ * the GT migration code, since it only accepts a single dependency
+ * fence.
+ * The single fence returned from these utilities, in the case of
+ * dependencies from multiple fence contexts, a struct dma_fence_array,
+ * since the i915 request code can break that up and await the individual
+ * fences.
+ *
+ * Once we can do async unbinding, this is also needed to coalesce
+ * the migration fence with the unbind fences.
+ *
+ * While collecting the individual dependencies, we store the refcounted
+ * struct dma_fence pointers in a realloc-managed pointer array, since
+ * that can be easily fed into a dma_fence_array. Other options are
+ * available, like for example an xarray for similarity with drm/sched.
+ * Can be changed easily if needed.
+ *
+ * A struct i915_deps need to be initialized using i915_deps_init().
+ * If i915_deps_add_dependency() or i915_deps_add_resv() return an
+ * error code they will internally call i915_deps_fini(), which frees
+ * all internal references and allocations. After a call to
+ * i915_deps_to_fence(), or i915_deps_sync(), the struct should similarly
+ * be viewed as uninitialized.
+ *
+ * We might want to break this out into a separate file as a utility.
+ */
+
+#define I915_DEPS_MIN_ALLOC_CHUNK 8U
+
+/**
+ * struct i915_deps - Collect dependencies into a single dma-fence
+ * @single: Storage for pointer if the collection is a single fence.
+ * @fence: Allocated array of fence pointers if more than a single fence;
+ * otherwise points to the address of @single.
+ * @num_deps: Current number of dependency fences.
+ * @fences_size: Size of the @fences array in number of pointers.
+ * @gfp: Allocation mode.
+ */
+struct i915_deps {
+ struct dma_fence *single;
+ struct dma_fence **fences;
+ unsigned int num_deps;
+ unsigned int fences_size;
+ gfp_t gfp;
+};
+
+static void i915_deps_reset_fences(struct i915_deps *deps)
+{
+ if (deps->fences != &deps->single)
+ kfree(deps->fences);
+ deps->num_deps = 0;
+ deps->fences_size = 1;
+ deps->fences = &deps->single;
+}
+
+static void i915_deps_init(struct i915_deps *deps, gfp_t gfp)
+{
+ deps->fences = NULL;
+ deps->gfp = gfp;
+ i915_deps_reset_fences(deps);
+}
+
+static void i915_deps_fini(struct i915_deps *deps)
+{
+ unsigned int i;
+
+ for (i = 0; i < deps->num_deps; ++i)
+ dma_fence_put(deps->fences[i]);
+
+ if (deps->fences != &deps->single)
+ kfree(deps->fences);
+}
+
+static int i915_deps_grow(struct i915_deps *deps, struct dma_fence *fence,
+ const struct ttm_operation_ctx *ctx)
+{
+ int ret;
+
+ if (deps->num_deps >= deps->fences_size) {
+ unsigned int new_size = 2 * deps->fences_size;
+ struct dma_fence **new_fences;
+
+ new_size = max(new_size, I915_DEPS_MIN_ALLOC_CHUNK);
+ new_fences = kmalloc_array(new_size, sizeof(*new_fences), deps->gfp);
+ if (!new_fences)
+ goto sync;
+
+ memcpy(new_fences, deps->fences,
+ deps->fences_size * sizeof(*new_fences));
+ swap(new_fences, deps->fences);
+ if (new_fences != &deps->single)
+ kfree(new_fences);
+ deps->fences_size = new_size;
+ }
+ deps->fences[deps->num_deps++] = dma_fence_get(fence);
+ return 0;
+
+sync:
+ if (ctx->no_wait_gpu && !dma_fence_is_signaled(fence)) {
+ ret = -EBUSY;
+ goto unref;
+ }
+
+ ret = dma_fence_wait(fence, ctx->interruptible);
+ if (ret)
+ goto unref;
+
+ ret = fence->error;
+ if (ret)
+ goto unref;
+
+ return 0;
+
+unref:
+ i915_deps_fini(deps);
+ return ret;
+}
+
+static int i915_deps_sync(struct i915_deps *deps,
+ const struct ttm_operation_ctx *ctx)
+{
+ struct dma_fence **fences = deps->fences;
+ unsigned int i;
+ int ret = 0;
+
+ for (i = 0; i < deps->num_deps; ++i, ++fences) {
+ if (ctx->no_wait_gpu && !dma_fence_is_signaled(*fences)) {
+ ret = -EBUSY;
+ break;
+ }
+
+ ret = dma_fence_wait(*fences, ctx->interruptible);
+ if (!ret)
+ ret = (*fences)->error;
+ if (ret)
+ break;
+ }
+
+ i915_deps_fini(deps);
+ return ret;
+}
+
+static int i915_deps_add_dependency(struct i915_deps *deps,
+ struct dma_fence *fence,
+ const struct ttm_operation_ctx *ctx)
+{
+ unsigned int i;
+ int ret;
+
+ if (!fence)
+ return 0;
+
+ if (dma_fence_is_signaled(fence)) {
+ ret = fence->error;
+ if (ret)
+ i915_deps_fini(deps);
+ return ret;
+ }
+
+ for (i = 0; i < deps->num_deps; ++i) {
+ struct dma_fence *entry = deps->fences[i];
+
+ if (!entry->context || entry->context != fence->context)
+ continue;
+
+ if (dma_fence_is_later(fence, entry)) {
+ dma_fence_put(entry);
+ deps->fences[i] = dma_fence_get(fence);
+ }
+
+ return 0;
+ }
+
+ return i915_deps_grow(deps, fence, ctx);
+}
+
+static struct dma_fence *i915_deps_to_fence(struct i915_deps *deps,
+ const struct ttm_operation_ctx *ctx)
+{
+ struct dma_fence_array *array;
+
+ if (deps->num_deps == 0)
+ return NULL;
+
+ if (deps->num_deps == 1) {
+ deps->num_deps = 0;
+ return deps->fences[0];
+ }
+
+ /*
+ * TODO: Alter the allocation mode here to not try too hard to
+ * make things async.
+ */
+ array = dma_fence_array_create(deps->num_deps, deps->fences, 0, 0,
+ false);
+ if (!array)
+ return ERR_PTR(i915_deps_sync(deps, ctx));
+
+ deps->fences = NULL;
+ i915_deps_reset_fences(deps);
+
+ return &array->base;
+}
+
+static int i915_deps_add_resv(struct i915_deps *deps, struct dma_resv *resv,
+ bool all, const bool no_excl,
+ const struct ttm_operation_ctx *ctx)
+{
+ struct dma_resv_iter iter;
+ struct dma_fence *fence;
+
+ dma_resv_assert_held(resv);
+ dma_resv_for_each_fence(&iter, resv, all, fence) {
+ int ret;
+
+ if (no_excl && dma_resv_iter_is_exclusive(&iter))
+ continue;
+
+ ret = i915_deps_add_dependency(deps, fence, ctx);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
static enum i915_cache_level
i915_ttm_cache_level(struct drm_i915_private *i915, struct ttm_resource *res,
struct ttm_tt *ttm)
@@ -156,7 +386,8 @@ static struct dma_fence *i915_ttm_accel_move(struct ttm_buffer_object *bo,
bool clear,
struct ttm_resource *dst_mem,
struct ttm_tt *dst_ttm,
- struct sg_table *dst_st)
+ struct sg_table *dst_st,
+ struct dma_fence *dep)
{
struct drm_i915_private *i915 = container_of(bo->bdev, typeof(*i915),
bdev);
@@ -180,7 +411,7 @@ static struct dma_fence *i915_ttm_accel_move(struct ttm_buffer_object *bo,
return ERR_PTR(-EINVAL);
intel_engine_pm_get(i915->gt.migrate.context->engine);
- ret = intel_context_migrate_clear(i915->gt.migrate.context, NULL,
+ ret = intel_context_migrate_clear(i915->gt.migrate.context, dep,
dst_st->sgl, dst_level,
i915_ttm_gtt_binds_lmem(dst_mem),
0, &rq);
@@ -194,7 +425,7 @@ static struct dma_fence *i915_ttm_accel_move(struct ttm_buffer_object *bo,
src_level = i915_ttm_cache_level(i915, bo->resource, src_ttm);
intel_engine_pm_get(i915->gt.migrate.context->engine);
ret = intel_context_migrate_copy(i915->gt.migrate.context,
- NULL, src_rsgt->table.sgl,
+ dep, src_rsgt->table.sgl,
src_level,
i915_ttm_gtt_binds_lmem(bo->resource),
dst_st->sgl, dst_level,
@@ -378,10 +609,11 @@ i915_ttm_memcpy_work_arm(struct i915_ttm_memcpy_work *work,
return &work->fence;
}
-static void __i915_ttm_move(struct ttm_buffer_object *bo, bool clear,
- struct ttm_resource *dst_mem,
- struct ttm_tt *dst_ttm,
- struct i915_refct_sgt *dst_rsgt, bool allow_accel)
+static struct dma_fence *
+__i915_ttm_move(struct ttm_buffer_object *bo, bool clear,
+ struct ttm_resource *dst_mem, struct ttm_tt *dst_ttm,
+ struct i915_refct_sgt *dst_rsgt, bool allow_accel,
+ struct dma_fence *move_dep)
{
struct i915_ttm_memcpy_work *copy_work = NULL;
struct i915_ttm_memcpy_arg _arg, *arg = &_arg;
@@ -389,7 +621,7 @@ static void __i915_ttm_move(struct ttm_buffer_object *bo, bool clear,
if (allow_accel) {
fence = i915_ttm_accel_move(bo, clear, dst_mem, dst_ttm,
- &dst_rsgt->table);
+ &dst_rsgt->table, move_dep);
/*
* We only need to intercept the error when moving to lmem.
@@ -423,6 +655,11 @@ static void __i915_ttm_move(struct ttm_buffer_object *bo, bool clear,
if (!IS_ERR(fence))
goto out;
+ } else if (move_dep) {
+ int err = dma_fence_wait(move_dep, true);
+
+ if (err)
+ return ERR_PTR(err);
}
/* Error intercept failed or no accelerated migration to start with */
@@ -433,16 +670,39 @@ static void __i915_ttm_move(struct ttm_buffer_object *bo, bool clear,
i915_ttm_memcpy_release(arg);
kfree(copy_work);
- return;
+ return NULL;
out:
- /* Sync here for now, forward the fence to caller when fully async. */
- if (fence) {
- dma_fence_wait(fence, false);
- dma_fence_put(fence);
- } else if (copy_work) {
+ if (!fence && copy_work) {
i915_ttm_memcpy_release(arg);
kfree(copy_work);
}
+
+ return fence;
+}
+
+static struct dma_fence *prev_fence(struct ttm_buffer_object *bo,
+ struct ttm_operation_ctx *ctx)
+{
+ struct i915_deps deps;
+ int ret;
+
+ /*
+ * Instead of trying hard with GFP_KERNEL to allocate memory,
+ * the dependency collection will just sync if it doesn't
+ * succeed.
+ */
+ i915_deps_init(&deps, GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
+ ret = i915_deps_add_dependency(&deps, bo->moving, ctx);
+ if (!ret)
+ /*
+ * TODO: Only await excl fence here, and shared fences before
+ * signaling the migration fence.
+ */
+ ret = i915_deps_add_resv(&deps, bo->base.resv, true, false, ctx);
+ if (ret)
+ return ERR_PTR(ret);
+
+ return i915_deps_to_fence(&deps, ctx);
}
/**
@@ -462,15 +722,16 @@ int i915_ttm_move(struct ttm_buffer_object *bo, bool evict,
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
struct ttm_resource_manager *dst_man =
ttm_manager_type(bo->bdev, dst_mem->mem_type);
+ struct dma_fence *migration_fence = NULL;
struct ttm_tt *ttm = bo->ttm;
struct i915_refct_sgt *dst_rsgt;
bool clear;
int ret;
- /* Sync for now. We could do the actual copy async. */
- ret = ttm_bo_wait_ctx(bo, ctx);
- if (ret)
- return ret;
+ if (GEM_WARN_ON(!obj)) {
+ ttm_bo_move_null(bo, dst_mem);
+ return 0;
+ }
ret = i915_ttm_move_notify(bo);
if (ret)
@@ -494,10 +755,37 @@ int i915_ttm_move(struct ttm_buffer_object *bo, bool evict,
return PTR_ERR(dst_rsgt);
clear = !i915_ttm_cpu_maps_iomem(bo->resource) && (!ttm || !ttm_tt_is_populated(ttm));
- if (!(clear && ttm && !(ttm->page_flags & TTM_TT_FLAG_ZERO_ALLOC)))
- __i915_ttm_move(bo, clear, dst_mem, bo->ttm, dst_rsgt, true);
+ if (!(clear && ttm && !(ttm->page_flags & TTM_TT_FLAG_ZERO_ALLOC))) {
+ struct dma_fence *dep = prev_fence(bo, ctx);
+
+ if (IS_ERR(dep)) {
+ i915_refct_sgt_put(dst_rsgt);
+ return PTR_ERR(dep);
+ }
+
+ migration_fence = __i915_ttm_move(bo, clear, dst_mem, bo->ttm,
+ dst_rsgt, true, dep);
+ dma_fence_put(dep);
+ }
+
+ /* We can possibly get an -ERESTARTSYS here */
+ if (IS_ERR(migration_fence)) {
+ i915_refct_sgt_put(dst_rsgt);
+ return PTR_ERR(migration_fence);
+ }
+
+ if (migration_fence) {
+ ret = ttm_bo_move_accel_cleanup(bo, migration_fence, evict,
+ true, dst_mem);
+ if (ret) {
+ dma_fence_wait(migration_fence, false);
+ ttm_bo_move_sync_cleanup(bo, dst_mem);
+ }
+ dma_fence_put(migration_fence);
+ } else {
+ ttm_bo_move_sync_cleanup(bo, dst_mem);
+ }
- ttm_bo_move_sync_cleanup(bo, dst_mem);
i915_ttm_adjust_domains_after_move(obj);
i915_ttm_free_cached_io_rsgt(obj);
@@ -538,6 +826,7 @@ int i915_gem_obj_copy_ttm(struct drm_i915_gem_object *dst,
.interruptible = intr,
};
struct i915_refct_sgt *dst_rsgt;
+ struct dma_fence *copy_fence;
int ret;
assert_object_held(dst);
@@ -553,10 +842,17 @@ int i915_gem_obj_copy_ttm(struct drm_i915_gem_object *dst,
return ret;
dst_rsgt = i915_ttm_resource_get_st(dst, dst_bo->resource);
- __i915_ttm_move(src_bo, false, dst_bo->resource, dst_bo->ttm,
- dst_rsgt, allow_accel);
+ copy_fence = __i915_ttm_move(src_bo, false, dst_bo->resource,
+ dst_bo->ttm, dst_rsgt, allow_accel, NULL);
i915_refct_sgt_put(dst_rsgt);
+ if (IS_ERR(copy_fence))
+ return PTR_ERR(copy_fence);
+
+ if (copy_fence) {
+ dma_fence_wait(copy_fence, false);
+ dma_fence_put(copy_fence);
+ }
return 0;
}
@@ -262,6 +262,6 @@ int i915_gem_object_wait_migration(struct drm_i915_gem_object *obj,
unsigned int flags)
{
might_sleep();
- /* NOP for now. */
- return 0;
+
+ return i915_gem_object_wait_moving_fence(obj, !!(flags & I915_WAIT_INTERRUPTIBLE));
}