diff options
Diffstat (limited to 'drivers/gpu/drm/i915/i915_gem_gtt.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_gem_gtt.c | 298 |
1 files changed, 298 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c new file mode 100644 index 000000000..c5ee1567f --- /dev/null +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -0,0 +1,298 @@ +// 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 "display/intel_frontbuffer.h" +#include "gt/intel_gt.h" +#include "gt/intel_gt_requests.h" + +#include "i915_drv.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->pdev->dev, + pages->sgl, pages->nents, + PCI_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(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 *dev_priv = to_i915(obj->base.dev); + struct device *kdev = &dev_priv->drm.pdev->dev; + struct i915_ggtt *ggtt = &dev_priv->ggtt; + + if (unlikely(ggtt->do_idle_maps)) { + /* XXX This does not prevent more requests being submitted! */ + if (intel_gt_retire_requests_timeout(ggtt->vm.gt, + -MAX_SCHEDULE_TIMEOUT)) { + drm_err(&dev_priv->drm, + "Failed to wait for idle; VT'd may hang.\n"); + /* Wait a bit, in hopes it avoids the hang */ + udelay(10); + } + } + + dma_unmap_sg(kdev, pages->sgl, pages->nents, PCI_DMA_BIDIRECTIONAL); +} + +/** + * i915_gem_gtt_reserve - reserve a node in an address_space (GTT) + * @vm: the &struct i915_address_space + * @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 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 == &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, 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_long(); + } else { + addr = get_random_int(); + if (range > U32_MAX) { + addr <<= 32; + addr |= get_random_int(); + } + } + 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 + * @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 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 == &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, 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, 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 |