[PATCH] drm/i915: Optionally manage system memory with TTM and poolalloc

Adrian Larumbe adrian.larumbe at collabora.com
Tue Jul 26 17:30:09 UTC 2022


Adds a module parameter that enables selection of the memory region manager
for system memory, either the legacy shmem-based one or TTM, through its
pool allocator. This could should not affect how DGFX platforms with LMEM
work.

Signed-off-by: Adrian Larumbe <adrian.larumbe at collabora.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_mman.c   | 56 ++++++++++----
 drivers/gpu/drm/i915/gem/i915_gem_ttm.c    | 86 +++++++++++++++++++++-
 drivers/gpu/drm/i915/gem/i915_gem_ttm.h    |  9 +++
 drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c   |  6 +-
 drivers/gpu/drm/i915/i915_params.c         |  6 ++
 drivers/gpu/drm/i915/i915_params.h         |  4 +-
 drivers/gpu/drm/i915/intel_memory_region.c | 10 ++-
 7 files changed, 156 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index 0c5c43852e24..b8ae6a381108 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -83,6 +83,22 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
 	if (!obj)
 		return -ENOENT;
 
+	if (range_overflows(args->offset, args->size, (u64)obj->base.size)) {
+		addr = -EINVAL;
+		goto err;
+	}
+
+	if (i915_gem_object_is_ttm(obj)) {
+		GEM_WARN_ON(!i915->params.use_pool_alloc);
+
+		addr = i915_gem_ttm_mmap(obj, args);
+		if (IS_ERR_VALUE(addr))
+			goto err;
+
+		args->addr_ptr = (u64)addr;
+		return 0;
+	}
+
 	/* prime objects have no backing filp to GEM mmap
 	 * pages from.
 	 */
@@ -91,11 +107,6 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
 		goto err;
 	}
 
-	if (range_overflows(args->offset, args->size, (u64)obj->base.size)) {
-		addr = -EINVAL;
-		goto err;
-	}
-
 	addr = vm_mmap(obj->base.filp, 0, args->size,
 		       PROT_READ | PROT_WRITE, MAP_SHARED,
 		       args->offset);
@@ -552,9 +563,11 @@ void i915_gem_object_release_mmap_gtt(struct drm_i915_gem_object *obj)
 
 void i915_gem_object_release_mmap_offset(struct drm_i915_gem_object *obj)
 {
+	struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
 	struct i915_mmap_offset *mmo, *mn;
 
-	if (obj->ops->unmap_virtual)
+	if (obj->ops->unmap_virtual &&
+	    bo->type == ttm_bo_type_device)
 		obj->ops->unmap_virtual(obj);
 
 	spin_lock(&obj->mmo.lock);
@@ -641,11 +654,13 @@ mmap_offset_attach(struct drm_i915_gem_object *obj,
 		   enum i915_mmap_type mmap_type,
 		   struct drm_file *file)
 {
+	struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
 	struct drm_i915_private *i915 = to_i915(obj->base.dev);
 	struct i915_mmap_offset *mmo;
 	int err;
 
-	GEM_BUG_ON(obj->ops->mmap_offset || obj->ops->mmap_ops);
+	GEM_BUG_ON((obj->ops->mmap_offset || obj->ops->mmap_ops) &&
+		   bo->type == ttm_bo_type_device);
 
 	mmo = lookup_mmo(obj, mmap_type);
 	if (mmo)
@@ -694,12 +709,14 @@ __assign_mmap_offset(struct drm_i915_gem_object *obj,
 		     enum i915_mmap_type mmap_type,
 		     u64 *offset, struct drm_file *file)
 {
+	struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
 	struct i915_mmap_offset *mmo;
 
 	if (i915_gem_object_never_mmap(obj))
 		return -ENODEV;
 
-	if (obj->ops->mmap_offset)  {
+	if (obj->ops->mmap_offset &&
+	    bo->type == ttm_bo_type_device)  {
 		if (mmap_type != I915_MMAP_TYPE_FIXED)
 			return -ENODEV;
 
@@ -731,7 +748,6 @@ __assign_mmap_offset_handle(struct drm_file *file,
 {
 	struct drm_i915_gem_object *obj;
 	int err;
-
 	obj = i915_gem_object_lookup(file, handle);
 	if (!obj)
 		return -ENOENT;
@@ -739,6 +755,7 @@ __assign_mmap_offset_handle(struct drm_file *file,
 	err = i915_gem_object_lock_interruptible(obj, NULL);
 	if (err)
 		goto out_put;
+
 	err = __assign_mmap_offset(obj, mmap_type, offset, file);
 	i915_gem_object_unlock(obj);
 out_put:
@@ -922,7 +939,9 @@ int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma)
 	struct drm_vma_offset_node *node;
 	struct drm_file *priv = filp->private_data;
 	struct drm_device *dev = priv->minor->dev;
+	struct drm_i915_private *i915 = to_i915(dev);
 	struct drm_i915_gem_object *obj = NULL;
+	struct ttm_buffer_object *bo = NULL;
 	struct i915_mmap_offset *mmo = NULL;
 	struct file *anon;
 
@@ -944,7 +963,8 @@ int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma)
 			mmo = container_of(node, struct i915_mmap_offset, vma_node);
 			obj = i915_gem_object_get_rcu(mmo->obj);
 
-			GEM_BUG_ON(obj && obj->ops->mmap_ops);
+			if (!i915->params.use_pool_alloc)
+				GEM_BUG_ON(obj && obj->ops->mmap_ops);
 		} else {
 			obj = i915_gem_object_get_rcu
 				(container_of(node, struct drm_i915_gem_object,
@@ -958,6 +978,9 @@ int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma)
 	if (!obj)
 		return node ? -EACCES : -EINVAL;
 
+	if (i915_gem_object_is_ttm(obj))
+		bo = i915_gem_to_ttm(obj);
+
 	if (i915_gem_object_is_readonly(obj)) {
 		if (vma->vm_flags & VM_WRITE) {
 			i915_gem_object_put(obj);
@@ -987,10 +1010,15 @@ int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma)
 	fput(anon);
 
 	if (obj->ops->mmap_ops) {
-		vma->vm_page_prot = pgprot_decrypted(vm_get_page_prot(vma->vm_flags));
-		vma->vm_ops = obj->ops->mmap_ops;
-		vma->vm_private_data = node->driver_private;
-		return 0;
+		/* there could be an obj backend with mmap_ops that isn't TTM */
+		if (!i915_gem_object_is_ttm(obj) ||
+		    (i915_gem_object_is_ttm(obj) &&
+		     bo->type == ttm_bo_type_device)) {
+			vma->vm_page_prot = pgprot_decrypted(vm_get_page_prot(vma->vm_flags));
+			vma->vm_ops = obj->ops->mmap_ops;
+			vma->vm_private_data = node->driver_private;
+			return 0;
+		}
 	}
 
 	vma->vm_private_data = mmo;
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 7e1f8b83077f..73598948d172 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -4,9 +4,11 @@
  */
 
 #include <linux/shmem_fs.h>
+#include <linux/mman.h>
 
 #include <drm/ttm/ttm_bo_driver.h>
 #include <drm/ttm/ttm_placement.h>
+#include <drm/ttm/ttm_bo_api.h>
 #include <drm/drm_buddy.h>
 
 #include "i915_drv.h"
@@ -20,6 +22,7 @@
 #include "gem/i915_gem_ttm.h"
 #include "gem/i915_gem_ttm_move.h"
 #include "gem/i915_gem_ttm_pm.h"
+#include "gem/i915_gem_clflush.h"
 #include "gt/intel_gpu_commands.h"
 
 #define I915_TTM_PRIO_PURGE     0
@@ -294,7 +297,8 @@ static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo,
 	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;
+
+		i915_tt->is_shmem = i915->params.use_pool_alloc ? false : true;
 	}
 
 	if (HAS_FLAT_CCS(i915) && i915_gem_object_needs_ccs_pages(obj))
@@ -513,9 +517,7 @@ static int i915_ttm_shrink(struct drm_i915_gem_object *obj, unsigned int flags)
 	if (!bo->ttm || bo->resource->mem_type != TTM_PL_SYSTEM)
 		return 0;
 
-	GEM_BUG_ON(!i915_tt->is_shmem);
-
-	if (!i915_tt->filp)
+	if (!ttm_tt_is_populated(bo->ttm))
 		return 0;
 
 	ret = ttm_bo_wait_ctx(bo, &ctx);
@@ -785,6 +787,16 @@ static int __i915_ttm_get_pages(struct drm_i915_gem_object *obj,
 	}
 
 	if (bo->ttm && !ttm_tt_is_populated(bo->ttm)) {
+		struct drm_i915_private *i915 = to_i915(obj->base.dev);
+		const size_t size = (size_t)bo->ttm->num_pages << PAGE_SHIFT;
+		struct intel_memory_region *mr = i915->mm.regions[INTEL_MEMORY_SYSTEM];
+		/*
+		 * If there's no chance of allocating enough pages for the whole
+		 * object, bail early.
+		 */
+		if (size > resource_size(&mr->region))
+			return -ENOMEM;
+
 		ret = ttm_tt_populate(bo->bdev, bo->ttm, &ctx);
 		if (ret)
 			return ret;
@@ -1215,6 +1227,11 @@ int __i915_gem_ttm_object_init(struct intel_memory_region *mem,
 	bo_type = (obj->flags & I915_BO_ALLOC_USER) ? ttm_bo_type_device :
 		ttm_bo_type_kernel;
 
+	if (!HAS_LMEM(i915) && i915->params.use_pool_alloc) {
+		GEM_WARN_ON(mem->type != INTEL_MEMORY_SYSTEM);
+		bo_type = ttm_bo_type_kernel;
+	}
+
 	obj->base.vma_node.driver_private = i915_gem_to_ttm(obj);
 
 	/* Forcing the page size is kernel internal only */
@@ -1274,3 +1291,64 @@ i915_gem_ttm_system_setup(struct drm_i915_private *i915,
 	intel_memory_region_set_name(mr, "system-ttm");
 	return mr;
 }
+
+bool i915_gem_object_is_ttm(const struct drm_i915_gem_object *obj)
+{
+	return obj->ops == &i915_gem_ttm_obj_ops;
+}
+
+struct drm_i915_gem_object *
+i915_gem_object_create_ttm_from_data(struct drm_i915_private *dev_priv,
+				       const void *data, resource_size_t size)
+{
+	struct drm_i915_gem_object *obj;
+	void *vaddr;
+
+	obj = i915_gem_object_create_shmem(dev_priv, round_up(size, PAGE_SIZE));
+	if (IS_ERR(obj))
+		return obj;
+
+	vaddr = i915_gem_object_pin_map_unlocked(obj, I915_MAP_WC);
+	if (IS_ERR(vaddr)) {
+		i915_gem_object_put(obj);
+		return vaddr;
+	}
+
+	memcpy(vaddr, data, size);
+
+	i915_gem_object_unpin_map(obj);
+
+	return obj;
+}
+
+unsigned long i915_gem_ttm_mmap(struct drm_i915_gem_object *obj,
+				struct drm_i915_gem_mmap *args)
+{
+	struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	unsigned long addr;
+
+	addr = vm_mmap(NULL, 0, args->size,
+		       PROT_READ | PROT_WRITE, MAP_SHARED,
+		       args->offset);
+	if (IS_ERR_VALUE(addr))
+		return addr;
+
+	if (mmap_write_lock_killable(mm))
+		return -EINTR;
+	vma = find_vma(current->mm, addr);
+	if (IS_ERR_VALUE(addr)) {
+		mmap_write_unlock(mm);
+		return addr;
+	}
+
+	vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP | VM_IO;
+	vma->vm_page_prot = pgprot_decrypted(vm_get_page_prot(vma->vm_flags));
+	vma->vm_ops = obj->ops->mmap_ops;
+	vma->vm_private_data = bo;
+
+	mmap_write_unlock(mm);
+
+	return addr;
+}
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.h b/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
index e4842b4296fc..2b1772a08c9f 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
@@ -95,4 +95,13 @@ static inline bool i915_ttm_cpu_maps_iomem(struct ttm_resource *mem)
 
 bool i915_ttm_resource_mappable(struct ttm_resource *res);
 
+bool i915_gem_object_is_ttm(const struct drm_i915_gem_object *obj);
+
+struct drm_i915_gem_object *
+i915_gem_object_create_ttm_from_data(struct drm_i915_private *dev_priv,
+				     const void *data, resource_size_t size);
+
+unsigned long i915_gem_ttm_mmap(struct drm_i915_gem_object *obj,
+				struct drm_i915_gem_mmap *args);
+
 #endif
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
index 27363091e1af..c40e58ae7f5c 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
@@ -11,6 +11,7 @@
 #include <drm/drm_print.h>
 
 #include "gem/i915_gem_lmem.h"
+#include "gem/i915_gem_ttm.h"
 #include "intel_uc_fw.h"
 #include "intel_uc_fw_abi.h"
 #include "i915_drv.h"
@@ -440,7 +441,10 @@ int intel_uc_fw_fetch(struct intel_uc_fw *uc_fw)
 		if (!IS_ERR(obj))
 			obj->flags |= I915_BO_ALLOC_PM_EARLY;
 	} else {
-		obj = i915_gem_object_create_shmem_from_data(i915, fw->data, fw->size);
+		if (unlikely(i915->params.use_pool_alloc))
+			obj = i915_gem_object_create_ttm_from_data(i915, fw->data, fw->size);
+		else
+			obj = i915_gem_object_create_shmem_from_data(i915, fw->data, fw->size);
 	}
 
 	if (IS_ERR(obj)) {
diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 701fbc98afa0..7200b1290954 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -205,6 +205,12 @@ i915_param_named_unsafe(request_timeout_ms, uint, 0600,
 i915_param_named_unsafe(lmem_size, uint, 0400,
 			"Set the lmem size(in MiB) for each region. (default: 0, all memory)");
 
+i915_param_named_unsafe(use_pool_alloc, bool, 0600,
+	"Force the driver to use TTM's pool allocator API for smem objects. "
+	"This will cause TTM to take over BO allocation even in integrated platforms. "
+	"(default: false)");
+
+
 static __always_inline void _print_param(struct drm_printer *p,
 					 const char *name,
 					 const char *type,
diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index b5e7ea45d191..eba54f021ec6 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -83,7 +83,9 @@ struct drm_printer;
 	param(bool, verbose_state_checks, true, 0) \
 	param(bool, nuclear_pageflip, false, 0400) \
 	param(bool, enable_dp_mst, true, 0600) \
-	param(bool, enable_gvt, false, IS_ENABLED(CONFIG_DRM_I915_GVT) ? 0400 : 0)
+	param(bool, enable_gvt, false, IS_ENABLED(CONFIG_DRM_I915_GVT) ? 0400 : 0) \
+	param(bool, use_pool_alloc, true, 0600)
+	/* set to 'true' for trybot testing */
 
 #define MEMBER(T, member, ...) T member;
 struct i915_params {
diff --git a/drivers/gpu/drm/i915/intel_memory_region.c b/drivers/gpu/drm/i915/intel_memory_region.c
index 9a4a7fb55582..8d72953b2c99 100644
--- a/drivers/gpu/drm/i915/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/intel_memory_region.c
@@ -310,6 +310,14 @@ int intel_memory_regions_hw_probe(struct drm_i915_private *i915)
 {
 	int err, i;
 
+	if (GRAPHICS_VER(i915) <= 5 &&
+	    i915->params.use_pool_alloc) {
+		drm_dbg(&i915->drm,
+			"TTM maybe not be used with GEN <=5 devices,"
+			" falling back on shmem\n");
+		i915->params.use_pool_alloc = false;
+	}
+
 	for (i = 0; i < ARRAY_SIZE(i915->mm.regions); i++) {
 		struct intel_memory_region *mem = ERR_PTR(-ENODEV);
 		u16 type, instance;
@@ -321,7 +329,7 @@ int intel_memory_regions_hw_probe(struct drm_i915_private *i915)
 		instance = intel_region_map[i].instance;
 		switch (type) {
 		case INTEL_MEMORY_SYSTEM:
-			if (IS_DGFX(i915))
+			if (IS_DGFX(i915) || i915->params.use_pool_alloc)
 				mem = i915_gem_ttm_system_setup(i915, type,
 								instance);
 			else
-- 
2.37.0



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