drivers/gpu/drm/i915/i915_gem_gtt.c - linux - Git at Google

 // SPDX-License-Identifier: MIT
 /*
  * Copyright © 2010 Daniel Vetter
  * Copyright © 2020 Intel Corporation
  */

 #include <linux/slab.h> /* fault-inject.h is not standalone! */

 #include <linux/fault-inject.h>
 #include <linux/log2.h>
 #include <linux/random.h>
 #include <linux/seq_file.h>
 #include <linux/stop_machine.h>

 #include <asm/set_memory.h>
 #include <asm/smp.h>

 #include "gt/intel_gt.h"
 #include "gt/intel_gt_requests.h"

 #include "i915_drv.h"
 #include "i915_gem_evict.h"
 #include "i915_scatterlist.h"
 #include "i915_trace.h"
 #include "i915_vgpu.h"

 int i915_gem_gtt_prepare_pages(struct drm_i915_gem_object *obj,
 			       struct sg_table *pages)
 {
 	do {
 		if (dma_map_sg_attrs(obj->base.dev->dev,
 				     pages->sgl, pages->nents,
 				     DMA_BIDIRECTIONAL,
 				     DMA_ATTR_SKIP_CPU_SYNC |
 				     DMA_ATTR_NO_KERNEL_MAPPING |
 				     DMA_ATTR_NO_WARN))
 			return 0;

 		/*
 		 * If the DMA remap fails, one cause can be that we have
 		 * too many objects pinned in a small remapping table,
 		 * such as swiotlb. Incrementally purge all other objects and
 		 * try again - if there are no more pages to remove from
 		 * the DMA remapper, i915_gem_shrink will return 0.
 		 */
 		GEM_BUG_ON(obj->mm.pages == pages);
 	} while (i915_gem_shrink(NULL, to_i915(obj->base.dev),
 				 obj->base.size >> PAGE_SHIFT, NULL,
 				 I915_SHRINK_BOUND |
 				 I915_SHRINK_UNBOUND));

 	return -ENOSPC;
 }

 void i915_gem_gtt_finish_pages(struct drm_i915_gem_object *obj,
 			       struct sg_table *pages)
 {
 	struct drm_i915_private *i915 = to_i915(obj->base.dev);
 	struct i915_ggtt *ggtt = to_gt(i915)->ggtt;

 	/* XXX This does not prevent more requests being submitted! */
 	if (unlikely(ggtt->do_idle_maps))
 		/* Wait a bit, in the hope it avoids the hang */
 		usleep_range(100, 250);

 	dma_unmap_sg(i915->drm.dev, pages->sgl, pages->nents,
 		     DMA_BIDIRECTIONAL);
 }

 /**
  * i915_gem_gtt_reserve - reserve a node in an address_space (GTT)
  * @vm: the &struct i915_address_space
  * @ww: An optional struct i915_gem_ww_ctx.
  * @node: the &struct drm_mm_node (typically i915_vma.mode)
  * @size: how much space to allocate inside the GTT,
  *        must be #I915_GTT_PAGE_SIZE aligned
  * @offset: where to insert inside the GTT,
  *          must be #I915_GTT_MIN_ALIGNMENT aligned, and the node
  *          (@offset + @size) must fit within the address space
  * @color: color to apply to node, if this node is not from a VMA,
  *         color must be #I915_COLOR_UNEVICTABLE
  * @flags: control search and eviction behaviour
  *
  * i915_gem_gtt_reserve() tries to insert the @node at the exact @offset inside
  * the address space (using @size and @color). If the @node does not fit, it
  * tries to evict any overlapping nodes from the GTT, including any
  * neighbouring nodes if the colors do not match (to ensure guard pages between
  * differing domains). See i915_gem_evict_for_node() for the gory details
  * on the eviction algorithm. #PIN_NONBLOCK may used to prevent waiting on
  * evicting active overlapping objects, and any overlapping node that is pinned
  * or marked as unevictable will also result in failure.
  *
  * Returns: 0 on success, -ENOSPC if no suitable hole is found, -EINTR if
  * asked to wait for eviction and interrupted.
  */
 int i915_gem_gtt_reserve(struct i915_address_space *vm,
 			 struct i915_gem_ww_ctx *ww,
 			 struct drm_mm_node *node,
 			 u64 size, u64 offset, unsigned long color,
 			 unsigned int flags)
 {
 	int err;

 	GEM_BUG_ON(!size);
 	GEM_BUG_ON(!IS_ALIGNED(size, I915_GTT_PAGE_SIZE));
 	GEM_BUG_ON(!IS_ALIGNED(offset, I915_GTT_MIN_ALIGNMENT));
 	GEM_BUG_ON(range_overflows(offset, size, vm->total));
 	GEM_BUG_ON(vm == &to_gt(vm->i915)->ggtt->alias->vm);
 	GEM_BUG_ON(drm_mm_node_allocated(node));

 	node->size = size;
 	node->start = offset;
 	node->color = color;

 	err = drm_mm_reserve_node(&vm->mm, node);
 	if (err != -ENOSPC)
 		return err;

 	if (flags & PIN_NOEVICT)
 		return -ENOSPC;

 	err = i915_gem_evict_for_node(vm, ww, node, flags);
 	if (err == 0)
 		err = drm_mm_reserve_node(&vm->mm, node);

 	return err;
 }

 static u64 random_offset(u64 start, u64 end, u64 len, u64 align)
 {
 	u64 range, addr;

 	GEM_BUG_ON(range_overflows(start, len, end));
 	GEM_BUG_ON(round_up(start, align) > round_down(end - len, align));

 	range = round_down(end - len, align) - round_up(start, align);
 	if (range) {
 		if (sizeof(unsigned long) == sizeof(u64)) {
 			addr = get_random_u64();
 		} else {
 			addr = get_random_u32();
 			if (range > U32_MAX) {
 				addr <<= 32;
 				addr |= get_random_u32();
 			}
 		}
 		div64_u64_rem(addr, range, &addr);
 		start += addr;
 	}

 	return round_up(start, align);
 }

 /**
  * i915_gem_gtt_insert - insert a node into an address_space (GTT)
  * @vm: the &struct i915_address_space
  * @ww: An optional struct i915_gem_ww_ctx.
  * @node: the &struct drm_mm_node (typically i915_vma.node)
  * @size: how much space to allocate inside the GTT,
  *        must be #I915_GTT_PAGE_SIZE aligned
  * @alignment: required alignment of starting offset, may be 0 but
  *             if specified, this must be a power-of-two and at least
  *             #I915_GTT_MIN_ALIGNMENT
  * @color: color to apply to node
  * @start: start of any range restriction inside GTT (0 for all),
  *         must be #I915_GTT_PAGE_SIZE aligned
  * @end: end of any range restriction inside GTT (U64_MAX for all),
  *       must be #I915_GTT_PAGE_SIZE aligned if not U64_MAX
  * @flags: control search and eviction behaviour
  *
  * i915_gem_gtt_insert() first searches for an available hole into which
  * is can insert the node. The hole address is aligned to @alignment and
  * its @size must then fit entirely within the [@start, @end] bounds. The
  * nodes on either side of the hole must match @color, or else a guard page
  * will be inserted between the two nodes (or the node evicted). If no
  * suitable hole is found, first a victim is randomly selected and tested
  * for eviction, otherwise then the LRU list of objects within the GTT
  * is scanned to find the first set of replacement nodes to create the hole.
  * Those old overlapping nodes are evicted from the GTT (and so must be
  * rebound before any future use). Any node that is currently pinned cannot
  * be evicted (see i915_vma_pin()). Similar if the node's VMA is currently
  * active and #PIN_NONBLOCK is specified, that node is also skipped when
  * searching for an eviction candidate. See i915_gem_evict_something() for
  * the gory details on the eviction algorithm.
  *
  * Returns: 0 on success, -ENOSPC if no suitable hole is found, -EINTR if
  * asked to wait for eviction and interrupted.
  */
 int i915_gem_gtt_insert(struct i915_address_space *vm,
 			struct i915_gem_ww_ctx *ww,
 			struct drm_mm_node *node,
 			u64 size, u64 alignment, unsigned long color,
 			u64 start, u64 end, unsigned int flags)
 {
 	enum drm_mm_insert_mode mode;
 	u64 offset;
 	int err;

 	lockdep_assert_held(&vm->mutex);

 	GEM_BUG_ON(!size);
 	GEM_BUG_ON(!IS_ALIGNED(size, I915_GTT_PAGE_SIZE));
 	GEM_BUG_ON(alignment && !is_power_of_2(alignment));
 	GEM_BUG_ON(alignment && !IS_ALIGNED(alignment, I915_GTT_MIN_ALIGNMENT));
 	GEM_BUG_ON(start >= end);
 	GEM_BUG_ON(start > 0  && !IS_ALIGNED(start, I915_GTT_PAGE_SIZE));
 	GEM_BUG_ON(end < U64_MAX && !IS_ALIGNED(end, I915_GTT_PAGE_SIZE));
 	GEM_BUG_ON(vm == &to_gt(vm->i915)->ggtt->alias->vm);
 	GEM_BUG_ON(drm_mm_node_allocated(node));

 	if (unlikely(range_overflows(start, size, end)))
 		return -ENOSPC;

 	if (unlikely(round_up(start, alignment) > round_down(end - size, alignment)))
 		return -ENOSPC;

 	mode = DRM_MM_INSERT_BEST;
 	if (flags & PIN_HIGH)
 		mode = DRM_MM_INSERT_HIGHEST;
 	if (flags & PIN_MAPPABLE)
 		mode = DRM_MM_INSERT_LOW;

 	/* We only allocate in PAGE_SIZE/GTT_PAGE_SIZE (4096) chunks,
 	 * so we know that we always have a minimum alignment of 4096.
 	 * The drm_mm range manager is optimised to return results
 	 * with zero alignment, so where possible use the optimal
 	 * path.
 	 */
 	BUILD_BUG_ON(I915_GTT_MIN_ALIGNMENT > I915_GTT_PAGE_SIZE);
 	if (alignment <= I915_GTT_MIN_ALIGNMENT)
 		alignment = 0;

 	err = drm_mm_insert_node_in_range(&vm->mm, node,
 					  size, alignment, color,
 					  start, end, mode);
 	if (err != -ENOSPC)
 		return err;

 	if (mode & DRM_MM_INSERT_ONCE) {
 		err = drm_mm_insert_node_in_range(&vm->mm, node,
 						  size, alignment, color,
 						  start, end,
 						  DRM_MM_INSERT_BEST);
 		if (err != -ENOSPC)
 			return err;
 	}

 	if (flags & PIN_NOEVICT)
 		return -ENOSPC;

 	/*
 	 * No free space, pick a slot at random.
 	 *
 	 * There is a pathological case here using a GTT shared between
 	 * mmap and GPU (i.e. ggtt/aliasing_ppgtt but not full-ppgtt):
 	 *
 	 *    |<-- 256 MiB aperture -->||<-- 1792 MiB unmappable -->|
 	 *         (64k objects)             (448k objects)
 	 *
 	 * Now imagine that the eviction LRU is ordered top-down (just because
 	 * pathology meets real life), and that we need to evict an object to
 	 * make room inside the aperture. The eviction scan then has to walk
 	 * the 448k list before it finds one within range. And now imagine that
 	 * it has to search for a new hole between every byte inside the memcpy,
 	 * for several simultaneous clients.
 	 *
 	 * On a full-ppgtt system, if we have run out of available space, there
 	 * will be lots and lots of objects in the eviction list! Again,
 	 * searching that LRU list may be slow if we are also applying any
 	 * range restrictions (e.g. restriction to low 4GiB) and so, for
 	 * simplicity and similarilty between different GTT, try the single
 	 * random replacement first.
 	 */
 	offset = random_offset(start, end,
 			       size, alignment ?: I915_GTT_MIN_ALIGNMENT);
 	err = i915_gem_gtt_reserve(vm, ww, node, size, offset, color, flags);
 	if (err != -ENOSPC)
 		return err;

 	if (flags & PIN_NOSEARCH)
 		return -ENOSPC;

 	/* Randomly selected placement is pinned, do a search */
 	err = i915_gem_evict_something(vm, ww, size, alignment, color,
 				       start, end, flags);
 	if (err)
 		return err;

 	return drm_mm_insert_node_in_range(&vm->mm, node,
 					   size, alignment, color,
 					   start, end, DRM_MM_INSERT_EVICT);
 }

 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 #include "selftests/i915_gem_gtt.c"
 #endif
	// SPDX-License-Identifier: MIT
	/*
	* Copyright © 2010 Daniel Vetter
	* Copyright © 2020 Intel Corporation
	*/

	#include <linux/slab.h> /* fault-inject.h is not standalone! */

	#include <linux/fault-inject.h>
	#include <linux/log2.h>
	#include <linux/random.h>
	#include <linux/seq_file.h>
	#include <linux/stop_machine.h>

	#include <asm/set_memory.h>
	#include <asm/smp.h>

	#include "gt/intel_gt.h"
	#include "gt/intel_gt_requests.h"

	#include "i915_drv.h"
	#include "i915_gem_evict.h"
	#include "i915_scatterlist.h"
	#include "i915_trace.h"
	#include "i915_vgpu.h"

	int i915_gem_gtt_prepare_pages(struct drm_i915_gem_object *obj,
	struct sg_table *pages)
	{
	do {
	if (dma_map_sg_attrs(obj->base.dev->dev,
	pages->sgl, pages->nents,
	DMA_BIDIRECTIONAL,
	DMA_ATTR_SKIP_CPU_SYNC \|
	DMA_ATTR_NO_KERNEL_MAPPING \|
	DMA_ATTR_NO_WARN))
	return 0;

	/*
	* If the DMA remap fails, one cause can be that we have
	* too many objects pinned in a small remapping table,
	* such as swiotlb. Incrementally purge all other objects and
	* try again - if there are no more pages to remove from
	* the DMA remapper, i915_gem_shrink will return 0.
	*/
	GEM_BUG_ON(obj->mm.pages == pages);
	} while (i915_gem_shrink(NULL, to_i915(obj->base.dev),
	obj->base.size >> PAGE_SHIFT, NULL,
	I915_SHRINK_BOUND \|
	I915_SHRINK_UNBOUND));

	return -ENOSPC;
	}

	void i915_gem_gtt_finish_pages(struct drm_i915_gem_object *obj,
	struct sg_table *pages)
	{
	struct drm_i915_private *i915 = to_i915(obj->base.dev);
	struct i915_ggtt *ggtt = to_gt(i915)->ggtt;

	/* XXX This does not prevent more requests being submitted! */
	if (unlikely(ggtt->do_idle_maps))
	/* Wait a bit, in the hope it avoids the hang */
	usleep_range(100, 250);

	dma_unmap_sg(i915->drm.dev, pages->sgl, pages->nents,
	DMA_BIDIRECTIONAL);
	}

	/**
	* i915_gem_gtt_reserve - reserve a node in an address_space (GTT)
	* @vm: the &struct i915_address_space
	* @ww: An optional struct i915_gem_ww_ctx.
	* @node: the &struct drm_mm_node (typically i915_vma.mode)
	* @size: how much space to allocate inside the GTT,
	* must be #I915_GTT_PAGE_SIZE aligned
	* @offset: where to insert inside the GTT,
	* must be #I915_GTT_MIN_ALIGNMENT aligned, and the node
	* (@offset + @size) must fit within the address space
	* @color: color to apply to node, if this node is not from a VMA,
	* color must be #I915_COLOR_UNEVICTABLE
	* @flags: control search and eviction behaviour
	*
	* i915_gem_gtt_reserve() tries to insert the @node at the exact @offset inside
	* the address space (using @size and @color). If the @node does not fit, it
	* tries to evict any overlapping nodes from the GTT, including any
	* neighbouring nodes if the colors do not match (to ensure guard pages between
	* differing domains). See i915_gem_evict_for_node() for the gory details
	* on the eviction algorithm. #PIN_NONBLOCK may used to prevent waiting on
	* evicting active overlapping objects, and any overlapping node that is pinned
	* or marked as unevictable will also result in failure.
	*
	* Returns: 0 on success, -ENOSPC if no suitable hole is found, -EINTR if
	* asked to wait for eviction and interrupted.
	*/
	int i915_gem_gtt_reserve(struct i915_address_space *vm,
	struct i915_gem_ww_ctx *ww,
	struct drm_mm_node *node,
	u64 size, u64 offset, unsigned long color,
	unsigned int flags)
	{
	int err;

	GEM_BUG_ON(!size);
	GEM_BUG_ON(!IS_ALIGNED(size, I915_GTT_PAGE_SIZE));
	GEM_BUG_ON(!IS_ALIGNED(offset, I915_GTT_MIN_ALIGNMENT));
	GEM_BUG_ON(range_overflows(offset, size, vm->total));
	GEM_BUG_ON(vm == &to_gt(vm->i915)->ggtt->alias->vm);
	GEM_BUG_ON(drm_mm_node_allocated(node));

	node->size = size;
	node->start = offset;
	node->color = color;

	err = drm_mm_reserve_node(&vm->mm, node);
	if (err != -ENOSPC)
	return err;

	if (flags & PIN_NOEVICT)
	return -ENOSPC;

	err = i915_gem_evict_for_node(vm, ww, node, flags);
	if (err == 0)
	err = drm_mm_reserve_node(&vm->mm, node);

	return err;
	}

	static u64 random_offset(u64 start, u64 end, u64 len, u64 align)
	{
	u64 range, addr;

	GEM_BUG_ON(range_overflows(start, len, end));
	GEM_BUG_ON(round_up(start, align) > round_down(end - len, align));

	range = round_down(end - len, align) - round_up(start, align);
	if (range) {
	if (sizeof(unsigned long) == sizeof(u64)) {
	addr = get_random_u64();
	} else {
	addr = get_random_u32();
	if (range > U32_MAX) {
	addr <<= 32;
	addr \|= get_random_u32();
	}
	}
	div64_u64_rem(addr, range, &addr);
	start += addr;
	}

	return round_up(start, align);
	}

	/**
	* i915_gem_gtt_insert - insert a node into an address_space (GTT)
	* @vm: the &struct i915_address_space
	* @ww: An optional struct i915_gem_ww_ctx.
	* @node: the &struct drm_mm_node (typically i915_vma.node)
	* @size: how much space to allocate inside the GTT,
	* must be #I915_GTT_PAGE_SIZE aligned
	* @alignment: required alignment of starting offset, may be 0 but
	* if specified, this must be a power-of-two and at least
	* #I915_GTT_MIN_ALIGNMENT
	* @color: color to apply to node
	* @start: start of any range restriction inside GTT (0 for all),
	* must be #I915_GTT_PAGE_SIZE aligned
	* @end: end of any range restriction inside GTT (U64_MAX for all),
	* must be #I915_GTT_PAGE_SIZE aligned if not U64_MAX
	* @flags: control search and eviction behaviour
	*
	* i915_gem_gtt_insert() first searches for an available hole into which
	* is can insert the node. The hole address is aligned to @alignment and
	* its @size must then fit entirely within the [@start, @end] bounds. The
	* nodes on either side of the hole must match @color, or else a guard page
	* will be inserted between the two nodes (or the node evicted). If no
	* suitable hole is found, first a victim is randomly selected and tested
	* for eviction, otherwise then the LRU list of objects within the GTT
	* is scanned to find the first set of replacement nodes to create the hole.
	* Those old overlapping nodes are evicted from the GTT (and so must be
	* rebound before any future use). Any node that is currently pinned cannot
	* be evicted (see i915_vma_pin()). Similar if the node's VMA is currently
	* active and #PIN_NONBLOCK is specified, that node is also skipped when
	* searching for an eviction candidate. See i915_gem_evict_something() for
	* the gory details on the eviction algorithm.
	*
	* Returns: 0 on success, -ENOSPC if no suitable hole is found, -EINTR if
	* asked to wait for eviction and interrupted.
	*/
	int i915_gem_gtt_insert(struct i915_address_space *vm,
	struct i915_gem_ww_ctx *ww,
	struct drm_mm_node *node,
	u64 size, u64 alignment, unsigned long color,
	u64 start, u64 end, unsigned int flags)
	{
	enum drm_mm_insert_mode mode;
	u64 offset;
	int err;

	lockdep_assert_held(&vm->mutex);

	GEM_BUG_ON(!size);
	GEM_BUG_ON(!IS_ALIGNED(size, I915_GTT_PAGE_SIZE));
	GEM_BUG_ON(alignment && !is_power_of_2(alignment));
	GEM_BUG_ON(alignment && !IS_ALIGNED(alignment, I915_GTT_MIN_ALIGNMENT));
	GEM_BUG_ON(start >= end);
	GEM_BUG_ON(start > 0 && !IS_ALIGNED(start, I915_GTT_PAGE_SIZE));
	GEM_BUG_ON(end < U64_MAX && !IS_ALIGNED(end, I915_GTT_PAGE_SIZE));
	GEM_BUG_ON(vm == &to_gt(vm->i915)->ggtt->alias->vm);
	GEM_BUG_ON(drm_mm_node_allocated(node));

	if (unlikely(range_overflows(start, size, end)))
	return -ENOSPC;

	if (unlikely(round_up(start, alignment) > round_down(end - size, alignment)))
	return -ENOSPC;

	mode = DRM_MM_INSERT_BEST;
	if (flags & PIN_HIGH)
	mode = DRM_MM_INSERT_HIGHEST;
	if (flags & PIN_MAPPABLE)
	mode = DRM_MM_INSERT_LOW;

	/* We only allocate in PAGE_SIZE/GTT_PAGE_SIZE (4096) chunks,
	* so we know that we always have a minimum alignment of 4096.
	* The drm_mm range manager is optimised to return results
	* with zero alignment, so where possible use the optimal
	* path.
	*/
	BUILD_BUG_ON(I915_GTT_MIN_ALIGNMENT > I915_GTT_PAGE_SIZE);
	if (alignment <= I915_GTT_MIN_ALIGNMENT)
	alignment = 0;

	err = drm_mm_insert_node_in_range(&vm->mm, node,
	size, alignment, color,
	start, end, mode);
	if (err != -ENOSPC)
	return err;

	if (mode & DRM_MM_INSERT_ONCE) {
	err = drm_mm_insert_node_in_range(&vm->mm, node,
	size, alignment, color,
	start, end,
	DRM_MM_INSERT_BEST);
	if (err != -ENOSPC)
	return err;
	}

	if (flags & PIN_NOEVICT)
	return -ENOSPC;

	/*
	* No free space, pick a slot at random.
	*
	* There is a pathological case here using a GTT shared between
	* mmap and GPU (i.e. ggtt/aliasing_ppgtt but not full-ppgtt):
	*
	* \|<-- 256 MiB aperture -->\|\|<-- 1792 MiB unmappable -->\|
	* (64k objects) (448k objects)
	*
	* Now imagine that the eviction LRU is ordered top-down (just because
	* pathology meets real life), and that we need to evict an object to
	* make room inside the aperture. The eviction scan then has to walk
	* the 448k list before it finds one within range. And now imagine that
	* it has to search for a new hole between every byte inside the memcpy,
	* for several simultaneous clients.
	*
	* On a full-ppgtt system, if we have run out of available space, there
	* will be lots and lots of objects in the eviction list! Again,
	* searching that LRU list may be slow if we are also applying any
	* range restrictions (e.g. restriction to low 4GiB) and so, for
	* simplicity and similarilty between different GTT, try the single
	* random replacement first.
	*/
	offset = random_offset(start, end,
	size, alignment ?: I915_GTT_MIN_ALIGNMENT);
	err = i915_gem_gtt_reserve(vm, ww, node, size, offset, color, flags);
	if (err != -ENOSPC)
	return err;

	if (flags & PIN_NOSEARCH)
	return -ENOSPC;

	/* Randomly selected placement is pinned, do a search */
	err = i915_gem_evict_something(vm, ww, size, alignment, color,
	start, end, flags);
	if (err)
	return err;

	return drm_mm_insert_node_in_range(&vm->mm, node,
	size, alignment, color,
	start, end, DRM_MM_INSERT_EVICT);
	}

	#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
	#include "selftests/i915_gem_gtt.c"
	#endif