// 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) { #ifdef __linux__ 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; #else return 0; #endif } 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); #ifdef notyet dma_unmap_sg(i915->drm.dev, pages->sgl, pages->nents, DMA_BIDIRECTIONAL); #endif } /** * 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.node) * @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
