Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

11 files changed, 2480 insertions, 0 deletions

diff --git a/third_party/rust/gpu-alloc/src/allocator.rs b/third_party/rust/gpu-alloc/src/allocator.rs
new file mode 100644
index 0000000000..80937c8d06
--- /dev/null
+++ b/third_party/rust/gpu-alloc/src/allocator.rs
@@ -0,0 +1,510 @@
+use {
+    crate::{
+        align_down,
+        block::{MemoryBlock, MemoryBlockFlavor},
+        buddy::{BuddyAllocator, BuddyBlock},
+        config::Config,
+        error::AllocationError,
+        freelist::{FreeListAllocator, FreeListBlock},
+        heap::Heap,
+        usage::{MemoryForUsage, UsageFlags},
+        MemoryBounds, Request,
+    },
+    alloc::boxed::Box,
+    core::convert::TryFrom as _,
+    gpu_alloc_types::{
+        AllocationFlags, DeviceProperties, MemoryDevice, MemoryPropertyFlags, MemoryType,
+        OutOfMemory,
+    },
+};
+
+/// Memory allocator for Vulkan-like APIs.
+#[derive(Debug)]
+pub struct GpuAllocator<M> {
+    dedicated_threshold: u64,
+    preferred_dedicated_threshold: u64,
+    transient_dedicated_threshold: u64,
+    max_memory_allocation_size: u64,
+    memory_for_usage: MemoryForUsage,
+    memory_types: Box<[MemoryType]>,
+    memory_heaps: Box<[Heap]>,
+    allocations_remains: u32,
+    non_coherent_atom_mask: u64,
+    starting_free_list_chunk: u64,
+    final_free_list_chunk: u64,
+    minimal_buddy_size: u64,
+    initial_buddy_dedicated_size: u64,
+    buffer_device_address: bool,
+
+    buddy_allocators: Box<[Option<BuddyAllocator<M>>]>,
+    freelist_allocators: Box<[Option<FreeListAllocator<M>>]>,
+}
+
+/// Hints for allocator to decide on allocation strategy.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+#[non_exhaustive]
+pub enum Dedicated {
+    /// Allocation directly from device.\
+    /// Very slow.
+    /// Count of allocations is limited.\
+    /// Use with caution.\
+    /// Must be used if resource has to be bound to dedicated memory object.
+    Required,
+
+    /// Hint for allocator that dedicated memory object is preferred.\
+    /// Should be used if it is known that resource placed in dedicated memory object
+    /// would allow for better performance.\
+    /// Implementation is allowed to return block to shared memory object.
+    Preferred,
+}
+
+impl<M> GpuAllocator<M>
+where
+    M: MemoryBounds + 'static,
+{
+    /// Creates  new instance of `GpuAllocator`.
+    /// Provided `DeviceProperties` should match properties of `MemoryDevice` that will be used
+    /// with created `GpuAllocator` instance.
+    #[cfg_attr(feature = "tracing", tracing::instrument)]
+    pub fn new(config: Config, props: DeviceProperties<'_>) -> Self {
+        assert!(
+            props.non_coherent_atom_size.is_power_of_two(),
+            "`non_coherent_atom_size` must be power of two"
+        );
+
+        assert!(
+            isize::try_from(props.non_coherent_atom_size).is_ok(),
+            "`non_coherent_atom_size` must fit host address space"
+        );
+
+        GpuAllocator {
+            dedicated_threshold: config.dedicated_threshold,
+            preferred_dedicated_threshold: config
+                .preferred_dedicated_threshold
+                .min(config.dedicated_threshold),
+
+            transient_dedicated_threshold: config
+                .transient_dedicated_threshold
+                .max(config.dedicated_threshold),
+
+            max_memory_allocation_size: props.max_memory_allocation_size,
+
+            memory_for_usage: MemoryForUsage::new(props.memory_types.as_ref()),
+
+            memory_types: props.memory_types.as_ref().iter().copied().collect(),
+            memory_heaps: props
+                .memory_heaps
+                .as_ref()
+                .iter()
+                .map(|heap| Heap::new(heap.size))
+                .collect(),
+
+            buffer_device_address: props.buffer_device_address,
+
+            allocations_remains: props.max_memory_allocation_count,
+            non_coherent_atom_mask: props.non_coherent_atom_size - 1,
+
+            starting_free_list_chunk: config.starting_free_list_chunk,
+            final_free_list_chunk: config.final_free_list_chunk,
+            minimal_buddy_size: config.minimal_buddy_size,
+            initial_buddy_dedicated_size: config.initial_buddy_dedicated_size,
+
+            buddy_allocators: props.memory_types.as_ref().iter().map(|_| None).collect(),
+            freelist_allocators: props.memory_types.as_ref().iter().map(|_| None).collect(),
+        }
+    }
+
+    /// Allocates memory block from specified `device` according to the `request`.
+    ///
+    /// # Safety
+    ///
+    /// * `device` must be one with `DeviceProperties` that were provided to create this `GpuAllocator` instance.
+    /// * Same `device` instance must be used for all interactions with one `GpuAllocator` instance
+    ///   and memory blocks allocated from it.
+    #[cfg_attr(feature = "tracing", tracing::instrument(skip(self, device)))]
+    pub unsafe fn alloc(
+        &mut self,
+        device: &impl MemoryDevice<M>,
+        request: Request,
+    ) -> Result<MemoryBlock<M>, AllocationError> {
+        self.alloc_internal(device, request, None)
+    }
+
+    /// Allocates memory block from specified `device` according to the `request`.
+    /// This function allows user to force specific allocation strategy.
+    /// Improper use can lead to suboptimal performance or too large overhead.
+    /// Prefer `GpuAllocator::alloc` if doubt.
+    ///
+    /// # Safety
+    ///
+    /// * `device` must be one with `DeviceProperties` that were provided to create this `GpuAllocator` instance.
+    /// * Same `device` instance must be used for all interactions with one `GpuAllocator` instance
+    ///   and memory blocks allocated from it.
+    #[cfg_attr(feature = "tracing", tracing::instrument(skip(self, device)))]
+    pub unsafe fn alloc_with_dedicated(
+        &mut self,
+        device: &impl MemoryDevice<M>,
+        request: Request,
+        dedicated: Dedicated,
+    ) -> Result<MemoryBlock<M>, AllocationError> {
+        self.alloc_internal(device, request, Some(dedicated))
+    }
+
+    unsafe fn alloc_internal(
+        &mut self,
+        device: &impl MemoryDevice<M>,
+        mut request: Request,
+        dedicated: Option<Dedicated>,
+    ) -> Result<MemoryBlock<M>, AllocationError> {
+        enum Strategy {
+            Buddy,
+            Dedicated,
+            FreeList,
+        }
+
+        request.usage = with_implicit_usage_flags(request.usage);
+
+        if request.usage.contains(UsageFlags::DEVICE_ADDRESS) {
+            assert!(self.buffer_device_address, "`DEVICE_ADDRESS` cannot be requested when `DeviceProperties::buffer_device_address` is false");
+        }
+
+        if request.size > self.max_memory_allocation_size {
+            return Err(AllocationError::OutOfDeviceMemory);
+        }
+
+        if let Some(Dedicated::Required) = dedicated {
+            if self.allocations_remains == 0 {
+                return Err(AllocationError::TooManyObjects);
+            }
+        }
+
+        if 0 == self.memory_for_usage.mask(request.usage) & request.memory_types {
+            #[cfg(feature = "tracing")]
+            tracing::error!(
+                "Cannot serve request {:?}, no memory among bitset `{}` support usage {:?}",
+                request,
+                request.memory_types,
+                request.usage
+            );
+
+            return Err(AllocationError::NoCompatibleMemoryTypes);
+        }
+
+        let transient = request.usage.contains(UsageFlags::TRANSIENT);
+
+        for &index in self.memory_for_usage.types(request.usage) {
+            if 0 == request.memory_types & (1 << index) {
+                // Skip memory type incompatible with the request.
+                continue;
+            }
+
+            let memory_type = &self.memory_types[index as usize];
+            let heap = memory_type.heap;
+            let heap = &mut self.memory_heaps[heap as usize];
+
+            let atom_mask = if host_visible_non_coherent(memory_type.props) {
+                self.non_coherent_atom_mask
+            } else {
+                0
+            };
+
+            let flags = if self.buffer_device_address {
+                AllocationFlags::DEVICE_ADDRESS
+            } else {
+                AllocationFlags::empty()
+            };
+
+            let strategy = match (dedicated, transient) {
+                (Some(Dedicated::Required), _) => Strategy::Dedicated,
+                (Some(Dedicated::Preferred), _)
+                    if request.size >= self.preferred_dedicated_threshold =>
+                {
+                    Strategy::Dedicated
+                }
+                (_, true) => {
+                    let threshold = self.transient_dedicated_threshold.min(heap.size() / 32);
+
+                    if request.size < threshold {
+                        Strategy::FreeList
+                    } else {
+                        Strategy::Dedicated
+                    }
+                }
+                (_, false) => {
+                    let threshold = self.dedicated_threshold.min(heap.size() / 32);
+
+                    if request.size < threshold {
+                        Strategy::Buddy
+                    } else {
+                        Strategy::Dedicated
+                    }
+                }
+            };
+
+            match strategy {
+                Strategy::Dedicated => {
+                    #[cfg(feature = "tracing")]
+                    tracing::debug!(
+                        "Allocating memory object `{}@{:?}`",
+                        request.size,
+                        memory_type
+                    );
+
+                    match device.allocate_memory(request.size, index, flags) {
+                        Ok(memory) => {
+                            self.allocations_remains -= 1;
+                            heap.alloc(request.size);
+
+                            return Ok(MemoryBlock::new(
+                                index,
+                                memory_type.props,
+                                0,
+                                request.size,
+                                atom_mask,
+                                MemoryBlockFlavor::Dedicated { memory },
+                            ));
+                        }
+                        Err(OutOfMemory::OutOfDeviceMemory) => continue,
+                        Err(OutOfMemory::OutOfHostMemory) => {
+                            return Err(AllocationError::OutOfHostMemory)
+                        }
+                    }
+                }
+                Strategy::FreeList => {
+                    let allocator = match &mut self.freelist_allocators[index as usize] {
+                        Some(allocator) => allocator,
+                        slot => {
+                            let starting_free_list_chunk = match align_down(
+                                self.starting_free_list_chunk.min(heap.size() / 32),
+                                atom_mask,
+                            ) {
+                                0 => atom_mask,
+                                other => other,
+                            };
+
+                            let final_free_list_chunk = match align_down(
+                                self.final_free_list_chunk
+                                    .max(self.starting_free_list_chunk)
+                                    .max(self.transient_dedicated_threshold)
+                                    .min(heap.size() / 32),
+                                atom_mask,
+                            ) {
+                                0 => atom_mask,
+                                other => other,
+                            };
+
+                            slot.get_or_insert(FreeListAllocator::new(
+                                starting_free_list_chunk,
+                                final_free_list_chunk,
+                                index,
+                                memory_type.props,
+                                if host_visible_non_coherent(memory_type.props) {
+                                    self.non_coherent_atom_mask
+                                } else {
+                                    0
+                                },
+                            ))
+                        }
+                    };
+                    let result = allocator.alloc(
+                        device,
+                        request.size,
+                        request.align_mask,
+                        flags,
+                        heap,
+                        &mut self.allocations_remains,
+                    );
+
+                    match result {
+                        Ok(block) => {
+                            return Ok(MemoryBlock::new(
+                                index,
+                                memory_type.props,
+                                block.offset,
+                                block.size,
+                                atom_mask,
+                                MemoryBlockFlavor::FreeList {
+                                    chunk: block.chunk,
+                                    ptr: block.ptr,
+                                    memory: block.memory,
+                                },
+                            ))
+                        }
+                        Err(AllocationError::OutOfDeviceMemory) => continue,
+                        Err(err) => return Err(err),
+                    }
+                }
+
+                Strategy::Buddy => {
+                    let allocator = match &mut self.buddy_allocators[index as usize] {
+                        Some(allocator) => allocator,
+                        slot => {
+                            let minimal_buddy_size = self
+                                .minimal_buddy_size
+                                .min(heap.size() / 1024)
+                                .next_power_of_two();
+
+                            let initial_buddy_dedicated_size = self
+                                .initial_buddy_dedicated_size
+                                .min(heap.size() / 32)
+                                .next_power_of_two();
+
+                            slot.get_or_insert(BuddyAllocator::new(
+                                minimal_buddy_size,
+                                initial_buddy_dedicated_size,
+                                index,
+                                memory_type.props,
+                                if host_visible_non_coherent(memory_type.props) {
+                                    self.non_coherent_atom_mask
+                                } else {
+                                    0
+                                },
+                            ))
+                        }
+                    };
+                    let result = allocator.alloc(
+                        device,
+                        request.size,
+                        request.align_mask,
+                        flags,
+                        heap,
+                        &mut self.allocations_remains,
+                    );
+
+                    match result {
+                        Ok(block) => {
+                            return Ok(MemoryBlock::new(
+                                index,
+                                memory_type.props,
+                                block.offset,
+                                block.size,
+                                atom_mask,
+                                MemoryBlockFlavor::Buddy {
+                                    chunk: block.chunk,
+                                    ptr: block.ptr,
+                                    index: block.index,
+                                    memory: block.memory,
+                                },
+                            ))
+                        }
+                        Err(AllocationError::OutOfDeviceMemory) => continue,
+                        Err(err) => return Err(err),
+                    }
+                }
+            }
+        }
+
+        Err(AllocationError::OutOfDeviceMemory)
+    }
+
+    /// Deallocates memory block previously allocated from this `GpuAllocator` instance.
+    ///
+    /// # Safety
+    ///
+    /// * Memory block must have been allocated by this `GpuAllocator` instance
+    /// * `device` must be one with `DeviceProperties` that were provided to create this `GpuAllocator` instance
+    /// * Same `device` instance must be used for all interactions with one `GpuAllocator` instance
+    ///   and memory blocks allocated from it
+    #[cfg_attr(feature = "tracing", tracing::instrument(skip(self, device)))]
+    pub unsafe fn dealloc(&mut self, device: &impl MemoryDevice<M>, block: MemoryBlock<M>) {
+        let memory_type = block.memory_type();
+        let offset = block.offset();
+        let size = block.size();
+        let flavor = block.deallocate();
+        match flavor {
+            MemoryBlockFlavor::Dedicated { memory } => {
+                let heap = self.memory_types[memory_type as usize].heap;
+                device.deallocate_memory(memory);
+                self.allocations_remains += 1;
+                self.memory_heaps[heap as usize].dealloc(size);
+            }
+            MemoryBlockFlavor::Buddy {
+                chunk,
+                ptr,
+                index,
+                memory,
+            } => {
+                let heap = self.memory_types[memory_type as usize].heap;
+                let heap = &mut self.memory_heaps[heap as usize];
+
+                let allocator = self.buddy_allocators[memory_type as usize]
+                    .as_mut()
+                    .expect("Allocator should exist");
+
+                allocator.dealloc(
+                    device,
+                    BuddyBlock {
+                        memory,
+                        ptr,
+                        offset,
+                        size,
+                        chunk,
+                        index,
+                    },
+                    heap,
+                    &mut self.allocations_remains,
+                );
+            }
+            MemoryBlockFlavor::FreeList { chunk, ptr, memory } => {
+                let heap = self.memory_types[memory_type as usize].heap;
+                let heap = &mut self.memory_heaps[heap as usize];
+
+                let allocator = self.freelist_allocators[memory_type as usize]
+                    .as_mut()
+                    .expect("Allocator should exist");
+
+                allocator.dealloc(
+                    device,
+                    FreeListBlock {
+                        memory,
+                        ptr,
+                        chunk,
+                        offset,
+                        size,
+                    },
+                    heap,
+                    &mut self.allocations_remains,
+                );
+            }
+        }
+    }
+
+    /// Deallocates leftover memory objects.
+    /// Should be used before dropping.
+    ///
+    /// # Safety
+    ///
+    /// * `device` must be one with `DeviceProperties` that were provided to create this `GpuAllocator` instance
+    /// * Same `device` instance must be used for all interactions with one `GpuAllocator` instance
+    ///   and memory blocks allocated from it
+    #[cfg_attr(feature = "tracing", tracing::instrument(skip(self, device)))]
+    pub unsafe fn cleanup(&mut self, device: &impl MemoryDevice<M>) {
+        for (index, allocator) in self
+            .freelist_allocators
+            .iter_mut()
+            .enumerate()
+            .filter_map(|(index, allocator)| Some((index, allocator.as_mut()?)))
+        {
+            let memory_type = &self.memory_types[index];
+            let heap = memory_type.heap;
+            let heap = &mut self.memory_heaps[heap as usize];
+
+            allocator.cleanup(device, heap, &mut self.allocations_remains);
+        }
+    }
+}
+
+fn host_visible_non_coherent(props: MemoryPropertyFlags) -> bool {
+    (props & (MemoryPropertyFlags::HOST_COHERENT | MemoryPropertyFlags::HOST_VISIBLE))
+        == MemoryPropertyFlags::HOST_VISIBLE
+}
+
+fn with_implicit_usage_flags(usage: UsageFlags) -> UsageFlags {
+    if usage.is_empty() {
+        UsageFlags::FAST_DEVICE_ACCESS
+    } else if usage.intersects(UsageFlags::DOWNLOAD | UsageFlags::UPLOAD) {
+        usage | UsageFlags::HOST_ACCESS
+    } else {
+        usage
+    }
+}
diff --git a/third_party/rust/gpu-alloc/src/block.rs b/third_party/rust/gpu-alloc/src/block.rs
new file mode 100644
index 0000000000..7cac633bf1
--- /dev/null
+++ b/third_party/rust/gpu-alloc/src/block.rs
@@ -0,0 +1,327 @@
+use {
+    crate::{align_down, align_up, error::MapError},
+    alloc::sync::Arc,
+    core::{
+        convert::TryFrom as _,
+        ptr::{copy_nonoverlapping, NonNull},
+        // sync::atomic::{AtomicU8, Ordering::*},
+    },
+    gpu_alloc_types::{MappedMemoryRange, MemoryDevice, MemoryPropertyFlags},
+};
+
+#[derive(Debug)]
+struct Relevant;
+
+impl Drop for Relevant {
+    fn drop(&mut self) {
+        report_error_on_drop!("Memory block wasn't deallocated");
+    }
+}
+
+/// Memory block allocated by `GpuAllocator`.
+#[derive(Debug)]
+pub struct MemoryBlock<M> {
+    memory_type: u32,
+    props: MemoryPropertyFlags,
+    offset: u64,
+    size: u64,
+    atom_mask: u64,
+    mapped: bool,
+    flavor: MemoryBlockFlavor<M>,
+    relevant: Relevant,
+}
+
+impl<M> MemoryBlock<M> {
+    pub(crate) fn new(
+        memory_type: u32,
+        props: MemoryPropertyFlags,
+        offset: u64,
+        size: u64,
+        atom_mask: u64,
+        flavor: MemoryBlockFlavor<M>,
+    ) -> Self {
+        isize::try_from(atom_mask).expect("`atom_mask` is too large");
+        MemoryBlock {
+            memory_type,
+            props,
+            offset,
+            size,
+            atom_mask,
+            flavor,
+            mapped: false,
+            relevant: Relevant,
+        }
+    }
+
+    pub(crate) fn deallocate(self) -> MemoryBlockFlavor<M> {
+        core::mem::forget(self.relevant);
+        self.flavor
+    }
+}
+
+unsafe impl<M> Sync for MemoryBlock<M> where M: Sync {}
+unsafe impl<M> Send for MemoryBlock<M> where M: Send {}
+
+#[derive(Debug)]
+pub(crate) enum MemoryBlockFlavor<M> {
+    Dedicated {
+        memory: M,
+    },
+    Buddy {
+        chunk: usize,
+        index: usize,
+        ptr: Option<NonNull<u8>>,
+        memory: Arc<M>,
+    },
+    FreeList {
+        chunk: u64,
+        ptr: Option<NonNull<u8>>,
+        memory: Arc<M>,
+    },
+}
+
+impl<M> MemoryBlock<M> {
+    /// Returns reference to parent memory object.
+    #[inline(always)]
+    pub fn memory(&self) -> &M {
+        match &self.flavor {
+            MemoryBlockFlavor::Dedicated { memory } => memory,
+            MemoryBlockFlavor::Buddy { memory, .. } => &**memory,
+            MemoryBlockFlavor::FreeList { memory, .. } => &**memory,
+        }
+    }
+
+    /// Returns offset in bytes from start of memory object to start of this block.
+    #[inline(always)]
+    pub fn offset(&self) -> u64 {
+        self.offset
+    }
+
+    /// Returns size of this memory block.
+    #[inline(always)]
+    pub fn size(&self) -> u64 {
+        self.size
+    }
+
+    /// Returns memory property flags for parent memory object.
+    #[inline(always)]
+    pub fn props(&self) -> MemoryPropertyFlags {
+        self.props
+    }
+
+    /// Returns index of type of parent memory object.
+    #[inline(always)]
+    pub fn memory_type(&self) -> u32 {
+        self.memory_type
+    }
+
+    /// Returns pointer to mapped memory range of this block.
+    /// This blocks becomes mapped.
+    ///
+    /// The user of returned pointer must guarantee that any previously submitted command that writes to this range has completed
+    /// before the host reads from or writes to that range,
+    /// and that any previously submitted command that reads from that range has completed
+    /// before the host writes to that region.
+    /// If the device memory was allocated without the `HOST_COHERENT` property flag set,
+    /// these guarantees must be made for an extended range:
+    /// the user must round down the start of the range to the nearest multiple of `non_coherent_atom_size`,
+    /// and round the end of the range up to the nearest multiple of `non_coherent_atom_size`.
+    ///
+    /// # Panics
+    ///
+    /// This function panics if block is currently mapped.
+    ///
+    /// # Safety
+    ///
+    /// `block` must have been allocated from specified `device`.
+    #[inline(always)]
+    pub unsafe fn map(
+        &mut self,
+        device: &impl MemoryDevice<M>,
+        offset: u64,
+        size: usize,
+    ) -> Result<NonNull<u8>, MapError> {
+        let size_u64 = u64::try_from(size).expect("`size` doesn't fit device address space");
+        assert!(offset < self.size, "`offset` is out of memory block bounds");
+        assert!(
+            size_u64 <= self.size - offset,
+            "`offset + size` is out of memory block bounds"
+        );
+
+        let ptr = match &mut self.flavor {
+            MemoryBlockFlavor::Dedicated { memory } => {
+                let end = align_up(offset + size_u64, self.atom_mask)
+                    .expect("mapping end doesn't fit device address space");
+                let aligned_offset = align_down(offset, self.atom_mask);
+
+                if !acquire_mapping(&mut self.mapped) {
+                    return Err(MapError::AlreadyMapped);
+                }
+                let result =
+                    device.map_memory(memory, self.offset + aligned_offset, end - aligned_offset);
+
+                match result {
+                    // the overflow is checked in `Self::new()`
+                    Ok(ptr) => {
+                        let ptr_offset = (offset - aligned_offset) as isize;
+                        ptr.as_ptr().offset(ptr_offset)
+                    }
+                    Err(err) => {
+                        release_mapping(&mut self.mapped);
+                        return Err(err.into());
+                    }
+                }
+            }
+            MemoryBlockFlavor::FreeList { ptr: Some(ptr), .. }
+            | MemoryBlockFlavor::Buddy { ptr: Some(ptr), .. } => {
+                if !acquire_mapping(&mut self.mapped) {
+                    return Err(MapError::AlreadyMapped);
+                }
+                let offset_isize = isize::try_from(offset)
+                    .expect("Buddy and linear block should fit host address space");
+                ptr.as_ptr().offset(offset_isize)
+            }
+            _ => return Err(MapError::NonHostVisible),
+        };
+
+        Ok(NonNull::new_unchecked(ptr))
+    }
+
+    /// Unmaps memory range of this block that was previously mapped with `Block::map`.
+    /// This block becomes unmapped.
+    ///
+    /// # Panics
+    ///
+    /// This function panics if this block is not currently mapped.
+    ///
+    /// # Safety
+    ///
+    /// `block` must have been allocated from specified `device`.
+    #[inline(always)]
+    pub unsafe fn unmap(&mut self, device: &impl MemoryDevice<M>) -> bool {
+        if !release_mapping(&mut self.mapped) {
+            return false;
+        }
+        match &mut self.flavor {
+            MemoryBlockFlavor::Dedicated { memory } => {
+                device.unmap_memory(memory);
+            }
+            MemoryBlockFlavor::Buddy { .. } => {}
+            MemoryBlockFlavor::FreeList { .. } => {}
+        }
+        true
+    }
+
+    /// Transiently maps block memory range and copies specified data
+    /// to the mapped memory range.
+    ///
+    /// # Panics
+    ///
+    /// This function panics if block is currently mapped.
+    ///
+    /// # Safety
+    ///
+    /// `block` must have been allocated from specified `device`.
+    /// The caller must guarantee that any previously submitted command that reads or writes to this range has completed.
+    #[inline(always)]
+    pub unsafe fn write_bytes(
+        &mut self,
+        device: &impl MemoryDevice<M>,
+        offset: u64,
+        data: &[u8],
+    ) -> Result<(), MapError> {
+        let size = data.len();
+        let ptr = self.map(device, offset, size)?;
+
+        copy_nonoverlapping(data.as_ptr(), ptr.as_ptr(), size);
+        let result = if !self.coherent() {
+            let aligned_offset = align_down(offset, self.atom_mask);
+            let end = align_up(offset + data.len() as u64, self.atom_mask).unwrap();
+
+            device.flush_memory_ranges(&[MappedMemoryRange {
+                memory: self.memory(),
+                offset: self.offset + aligned_offset,
+                size: end - aligned_offset,
+            }])
+        } else {
+            Ok(())
+        };
+
+        self.unmap(device);
+        result.map_err(Into::into)
+    }
+
+    /// Transiently maps block memory range and copies specified data
+    /// from the mapped memory range.
+    ///
+    /// # Panics
+    ///
+    /// This function panics if block is currently mapped.
+    ///
+    /// # Safety
+    ///
+    /// `block` must have been allocated from specified `device`.
+    /// The caller must guarantee that any previously submitted command that reads to this range has completed.
+    #[inline(always)]
+    pub unsafe fn read_bytes(
+        &mut self,
+        device: &impl MemoryDevice<M>,
+        offset: u64,
+        data: &mut [u8],
+    ) -> Result<(), MapError> {
+        #[cfg(feature = "tracing")]
+        {
+            if !self.cached() {
+                tracing::warn!("Reading from non-cached memory may be slow. Consider allocating HOST_CACHED memory block for host reads.")
+            }
+        }
+
+        let size = data.len();
+        let ptr = self.map(device, offset, size)?;
+        let result = if !self.coherent() {
+            let aligned_offset = align_down(offset, self.atom_mask);
+            let end = align_up(offset + data.len() as u64, self.atom_mask).unwrap();
+
+            device.invalidate_memory_ranges(&[MappedMemoryRange {
+                memory: self.memory(),
+                offset: self.offset + aligned_offset,
+                size: end - aligned_offset,
+            }])
+        } else {
+            Ok(())
+        };
+        if result.is_ok() {
+            copy_nonoverlapping(ptr.as_ptr(), data.as_mut_ptr(), size);
+        }
+
+        self.unmap(device);
+        result.map_err(Into::into)
+    }
+
+    fn coherent(&self) -> bool {
+        self.props.contains(MemoryPropertyFlags::HOST_COHERENT)
+    }
+
+    #[cfg(feature = "tracing")]
+    fn cached(&self) -> bool {
+        self.props.contains(MemoryPropertyFlags::HOST_CACHED)
+    }
+}
+
+fn acquire_mapping(mapped: &mut bool) -> bool {
+    if *mapped {
+        false
+    } else {
+        *mapped = true;
+        true
+    }
+}
+
+fn release_mapping(mapped: &mut bool) -> bool {
+    if *mapped {
+        *mapped = false;
+        true
+    } else {
+        false
+    }
+}
diff --git a/third_party/rust/gpu-alloc/src/buddy.rs b/third_party/rust/gpu-alloc/src/buddy.rs
new file mode 100644
index 0000000000..5691f4d96d
--- /dev/null
+++ b/third_party/rust/gpu-alloc/src/buddy.rs
@@ -0,0 +1,458 @@
+use {
+    crate::{
+        align_up, error::AllocationError, heap::Heap, slab::Slab, unreachable_unchecked,
+        util::try_arc_unwrap, MemoryBounds,
+    },
+    alloc::{sync::Arc, vec::Vec},
+    core::{convert::TryFrom as _, mem::replace, ptr::NonNull},
+    gpu_alloc_types::{AllocationFlags, DeviceMapError, MemoryDevice, MemoryPropertyFlags},
+};
+
+#[derive(Debug)]
+pub(crate) struct BuddyBlock<M> {
+    pub memory: Arc<M>,
+    pub ptr: Option<NonNull<u8>>,
+    pub offset: u64,
+    pub size: u64,
+    pub chunk: usize,
+    pub index: usize,
+}
+
+unsafe impl<M> Sync for BuddyBlock<M> where M: Sync {}
+unsafe impl<M> Send for BuddyBlock<M> where M: Send {}
+
+#[derive(Clone, Copy, Debug)]
+enum PairState {
+    Exhausted,
+    Ready {
+        ready: Side,
+        next: usize,
+        prev: usize,
+    },
+}
+
+impl PairState {
+    unsafe fn replace_next(&mut self, value: usize) -> usize {
+        match self {
+            PairState::Exhausted => unreachable_unchecked(),
+            PairState::Ready { next, .. } => replace(next, value),
+        }
+    }
+
+    unsafe fn replace_prev(&mut self, value: usize) -> usize {
+        match self {
+            PairState::Exhausted => unreachable_unchecked(),
+            PairState::Ready { prev, .. } => replace(prev, value),
+        }
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+enum Side {
+    Left,
+    Right,
+}
+use Side::*;
+
+#[derive(Debug)]
+struct PairEntry {
+    state: PairState,
+    chunk: usize,
+    offset: u64,
+    parent: Option<usize>,
+}
+
+struct SizeBlockEntry {
+    chunk: usize,
+    offset: u64,
+    index: usize,
+}
+
+#[derive(Debug)]
+struct Size {
+    next_ready: usize,
+    pairs: Slab<PairEntry>,
+}
+#[derive(Debug)]
+enum Release {
+    None,
+    Parent(usize),
+    Chunk(usize),
+}
+
+impl Size {
+    fn new() -> Self {
+        Size {
+            pairs: Slab::new(),
+            next_ready: 0,
+        }
+    }
+
+    unsafe fn add_pair_and_acquire_left(
+        &mut self,
+        chunk: usize,
+        offset: u64,
+        parent: Option<usize>,
+    ) -> SizeBlockEntry {
+        if self.next_ready < self.pairs.len() {
+            unreachable_unchecked()
+        }
+
+        let index = self.pairs.insert(PairEntry {
+            state: PairState::Exhausted,
+            chunk,
+            offset,
+            parent,
+        });
+
+        let entry = self.pairs.get_unchecked_mut(index);
+        entry.state = PairState::Ready {
+            next: index,
+            prev: index,
+            ready: Right, // Left is allocated.
+        };
+        self.next_ready = index;
+
+        SizeBlockEntry {
+            chunk,
+            offset,
+            index: index << 1,
+        }
+    }
+
+    fn acquire(&mut self, size: u64) -> Option<SizeBlockEntry> {
+        if self.next_ready >= self.pairs.len() {
+            return None;
+        }
+
+        let ready = self.next_ready;
+
+        let entry = unsafe { self.pairs.get_unchecked_mut(ready) };
+        let chunk = entry.chunk;
+        let offset = entry.offset;
+
+        let bit = match entry.state {
+            PairState::Exhausted => unsafe { unreachable_unchecked() },
+            PairState::Ready { ready, next, prev } => {
+                entry.state = PairState::Exhausted;
+
+                if prev == self.next_ready {
+                    // The only ready entry.
+                    debug_assert_eq!(next, self.next_ready);
+                    self.next_ready = self.pairs.len();
+                } else {
+                    let prev_entry = unsafe { self.pairs.get_unchecked_mut(prev) };
+                    let prev_next = unsafe { prev_entry.state.replace_next(next) };
+                    debug_assert_eq!(prev_next, self.next_ready);
+
+                    let next_entry = unsafe { self.pairs.get_unchecked_mut(next) };
+                    let next_prev = unsafe { next_entry.state.replace_prev(prev) };
+                    debug_assert_eq!(next_prev, self.next_ready);
+
+                    self.next_ready = next;
+                }
+
+                match ready {
+                    Left => 0,
+                    Right => 1,
+                }
+            }
+        };
+
+        Some(SizeBlockEntry {
+            chunk,
+            offset: offset + bit as u64 * size,
+            index: (ready << 1) | bit as usize,
+        })
+    }
+
+    fn release(&mut self, index: usize) -> Release {
+        let side = match index & 1 {
+            0 => Side::Left,
+            1 => Side::Right,
+            _ => unsafe { unreachable_unchecked() },
+        };
+        let entry_index = index >> 1;
+
+        let len = self.pairs.len();
+
+        let entry = self.pairs.get_mut(entry_index);
+
+        let chunk = entry.chunk;
+        let offset = entry.offset;
+        let parent = entry.parent;
+
+        match entry.state {
+            PairState::Exhausted => {
+                if self.next_ready == len {
+                    entry.state = PairState::Ready {
+                        ready: side,
+                        next: entry_index,
+                        prev: entry_index,
+                    };
+                    self.next_ready = entry_index;
+                } else {
+                    debug_assert!(self.next_ready < len);
+
+                    let next = self.next_ready;
+                    let next_entry = unsafe { self.pairs.get_unchecked_mut(next) };
+                    let prev = unsafe { next_entry.state.replace_prev(entry_index) };
+
+                    let prev_entry = unsafe { self.pairs.get_unchecked_mut(prev) };
+                    let prev_next = unsafe { prev_entry.state.replace_next(entry_index) };
+                    debug_assert_eq!(prev_next, next);
+
+                    let entry = unsafe { self.pairs.get_unchecked_mut(entry_index) };
+                    entry.state = PairState::Ready {
+                        ready: side,
+                        next,
+                        prev,
+                    };
+                }
+                Release::None
+            }
+
+            PairState::Ready { ready, .. } if ready == side => {
+                panic!("Attempt to dealloate already free block")
+            }
+
+            PairState::Ready { next, prev, .. } => {
+                unsafe {
+                    self.pairs.remove_unchecked(entry_index);
+                }
+
+                if prev == entry_index {
+                    debug_assert_eq!(next, entry_index);
+                    self.next_ready = self.pairs.len();
+                } else {
+                    let prev_entry = unsafe { self.pairs.get_unchecked_mut(prev) };
+                    let prev_next = unsafe { prev_entry.state.replace_next(next) };
+                    debug_assert_eq!(prev_next, entry_index);
+
+                    let next_entry = unsafe { self.pairs.get_unchecked_mut(next) };
+                    let next_prev = unsafe { next_entry.state.replace_prev(prev) };
+                    debug_assert_eq!(next_prev, entry_index);
+
+                    self.next_ready = next;
+                }
+
+                match parent {
+                    Some(parent) => Release::Parent(parent),
+                    None => {
+                        debug_assert_eq!(offset, 0);
+                        Release::Chunk(chunk)
+                    }
+                }
+            }
+        }
+    }
+}
+
+#[derive(Debug)]
+struct Chunk<M> {
+    memory: Arc<M>,
+    ptr: Option<NonNull<u8>>,
+    size: u64,
+}
+
+#[derive(Debug)]
+pub(crate) struct BuddyAllocator<M> {
+    minimal_size: u64,
+    chunks: Slab<Chunk<M>>,
+    sizes: Vec<Size>,
+    memory_type: u32,
+    props: MemoryPropertyFlags,
+    atom_mask: u64,
+}
+
+unsafe impl<M> Sync for BuddyAllocator<M> where M: Sync {}
+unsafe impl<M> Send for BuddyAllocator<M> where M: Send {}
+
+impl<M> BuddyAllocator<M>
+where
+    M: MemoryBounds + 'static,
+{
+    pub fn new(
+        minimal_size: u64,
+        initial_dedicated_size: u64,
+        memory_type: u32,
+        props: MemoryPropertyFlags,
+        atom_mask: u64,
+    ) -> Self {
+        assert!(
+            minimal_size.is_power_of_two(),
+            "Minimal allocation size of buddy allocator must be power of two"
+        );
+        assert!(
+            initial_dedicated_size.is_power_of_two(),
+            "Dedicated allocation size of buddy allocator must be power of two"
+        );
+
+        let initial_sizes = (initial_dedicated_size
+            .trailing_zeros()
+            .saturating_sub(minimal_size.trailing_zeros())) as usize;
+
+        BuddyAllocator {
+            minimal_size,
+            chunks: Slab::new(),
+            sizes: (0..initial_sizes).map(|_| Size::new()).collect(),
+            memory_type,
+            props,
+            atom_mask: atom_mask | (minimal_size - 1),
+        }
+    }
+
+    #[cfg_attr(feature = "tracing", tracing::instrument(skip(self, device)))]
+    pub unsafe fn alloc(
+        &mut self,
+        device: &impl MemoryDevice<M>,
+        size: u64,
+        align_mask: u64,
+        flags: AllocationFlags,
+        heap: &mut Heap,
+        allocations_remains: &mut u32,
+    ) -> Result<BuddyBlock<M>, AllocationError> {
+        let align_mask = align_mask | self.atom_mask;
+
+        let size = align_up(size, align_mask)
+            .and_then(|size| size.checked_next_power_of_two())
+            .ok_or(AllocationError::OutOfDeviceMemory)?;
+
+        let size_index = size.trailing_zeros() - self.minimal_size.trailing_zeros();
+        let size_index =
+            usize::try_from(size_index).map_err(|_| AllocationError::OutOfDeviceMemory)?;
+
+        while self.sizes.len() <= size_index {
+            self.sizes.push(Size::new());
+        }
+
+        let host_visible = self.host_visible();
+
+        let mut candidate_size_index = size_index;
+
+        let (mut entry, entry_size_index) = loop {
+            let sizes_len = self.sizes.len();
+
+            let candidate_size_entry = &mut self.sizes[candidate_size_index];
+            let candidate_size = self.minimal_size << candidate_size_index;
+
+            if let Some(entry) = candidate_size_entry.acquire(candidate_size) {
+                break (entry, candidate_size_index);
+            }
+
+            if sizes_len == candidate_size_index + 1 {
+                // That's size of device allocation.
+                if *allocations_remains == 0 {
+                    return Err(AllocationError::TooManyObjects);
+                }
+
+                let chunk_size = self.minimal_size << (candidate_size_index + 1);
+                let mut memory = device.allocate_memory(chunk_size, self.memory_type, flags)?;
+                *allocations_remains -= 1;
+                heap.alloc(chunk_size);
+
+                let ptr = if host_visible {
+                    match device.map_memory(&mut memory, 0, chunk_size) {
+                        Ok(ptr) => Some(ptr),
+                        Err(DeviceMapError::OutOfDeviceMemory) => {
+                            return Err(AllocationError::OutOfDeviceMemory)
+                        }
+                        Err(DeviceMapError::MapFailed) | Err(DeviceMapError::OutOfHostMemory) => {
+                            return Err(AllocationError::OutOfHostMemory)
+                        }
+                    }
+                } else {
+                    None
+                };
+
+                let chunk = self.chunks.insert(Chunk {
+                    memory: Arc::new(memory),
+                    ptr,
+                    size: chunk_size,
+                });
+
+                let entry = candidate_size_entry.add_pair_and_acquire_left(chunk, 0, None);
+
+                break (entry, candidate_size_index);
+            }
+
+            candidate_size_index += 1;
+        };
+
+        for size_index in (size_index..entry_size_index).rev() {
+            let size_entry = &mut self.sizes[size_index];
+            entry =
+                size_entry.add_pair_and_acquire_left(entry.chunk, entry.offset, Some(entry.index));
+        }
+
+        let chunk_entry = self.chunks.get_unchecked(entry.chunk);
+
+        debug_assert!(
+            entry
+                .offset
+                .checked_add(size)
+                .map_or(false, |end| end <= chunk_entry.size),
+            "Offset + size is not in chunk bounds"
+        );
+
+        Ok(BuddyBlock {
+            memory: chunk_entry.memory.clone(),
+            ptr: chunk_entry
+                .ptr
+                .map(|ptr| NonNull::new_unchecked(ptr.as_ptr().add(entry.offset as usize))),
+            offset: entry.offset,
+            size,
+            chunk: entry.chunk,
+            index: entry.index,
+        })
+    }
+
+    #[cfg_attr(feature = "tracing", tracing::instrument(skip(self, device)))]
+    pub unsafe fn dealloc(
+        &mut self,
+        device: &impl MemoryDevice<M>,
+        block: BuddyBlock<M>,
+        heap: &mut Heap,
+        allocations_remains: &mut u32,
+    ) {
+        debug_assert!(block.size.is_power_of_two());
+
+        let size_index =
+            (block.size.trailing_zeros() - self.minimal_size.trailing_zeros()) as usize;
+
+        let mut release_index = block.index;
+        let mut release_size_index = size_index;
+
+        loop {
+            match self.sizes[release_size_index].release(release_index) {
+                Release::Parent(parent) => {
+                    release_size_index += 1;
+                    release_index = parent;
+                }
+                Release::Chunk(chunk) => {
+                    debug_assert_eq!(chunk, block.chunk);
+                    debug_assert_eq!(
+                        self.chunks.get(chunk).size,
+                        self.minimal_size << (release_size_index + 1)
+                    );
+                    let chunk = self.chunks.remove(chunk);
+                    drop(block);
+
+                    let memory = try_arc_unwrap(chunk.memory)
+                        .expect("Memory shared after last block deallocated");
+
+                    device.deallocate_memory(memory);
+                    *allocations_remains += 1;
+                    heap.dealloc(chunk.size);
+
+                    return;
+                }
+                Release::None => return,
+            }
+        }
+    }
+
+    fn host_visible(&self) -> bool {
+        self.props.contains(MemoryPropertyFlags::HOST_VISIBLE)
+    }
+}
diff --git a/third_party/rust/gpu-alloc/src/config.rs b/third_party/rust/gpu-alloc/src/config.rs
new file mode 100644
index 0000000000..0d9da8070a
--- /dev/null
+++ b/third_party/rust/gpu-alloc/src/config.rs
@@ -0,0 +1,77 @@
+/// Configuration for [`GpuAllocator`]
+///
+/// [`GpuAllocator`]: type.GpuAllocator
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+pub struct Config {
+    /// Size in bytes of request that will be served by dedicated memory object.
+    /// This value should be large enough to not exhaust memory object limit
+    /// and not use slow memory object allocation when it is not necessary.
+    pub dedicated_threshold: u64,
+
+    /// Size in bytes of request that will be served by dedicated memory object if preferred.
+    /// This value should be large enough to not exhaust memory object limit
+    /// and not use slow memory object allocation when it is not necessary.
+    ///
+    /// This won't make much sense if this value is larger than `dedicated_threshold`.
+    pub preferred_dedicated_threshold: u64,
+
+    /// Size in bytes of transient memory request that will be served by dedicated memory object.
+    /// This value should be large enough to not exhaust memory object limit
+    /// and not use slow memory object allocation when it is not necessary.
+    ///
+    /// This won't make much sense if this value is lesser than `dedicated_threshold`.
+    pub transient_dedicated_threshold: u64,
+
+    /// Size in bytes of first chunk in free-list allocator.
+    pub starting_free_list_chunk: u64,
+
+    /// Upper limit for size in bytes of chunks in free-list allocator.
+    pub final_free_list_chunk: u64,
+
+    /// Minimal size for buddy allocator.
+    pub minimal_buddy_size: u64,
+
+    /// Initial memory object size for buddy allocator.
+    /// If less than `minimal_buddy_size` then `minimal_buddy_size` is used instead.
+    pub initial_buddy_dedicated_size: u64,
+}
+
+impl Config {
+    /// Returns default configuration.
+    ///
+    /// This is not `Default` implementation to discourage usage outside of
+    /// prototyping.
+    ///
+    /// Proper configuration should depend on hardware and intended usage.\
+    /// But those values can be used as starting point.\
+    /// Note that they can simply not work for some platforms with lesser
+    /// memory capacity than today's "modern" GPU (year 2020).
+    pub fn i_am_prototyping() -> Self {
+        // Assume that today's modern GPU is made of 1024 potatoes.
+        let potato = Config::i_am_potato();
+
+        Config {
+            dedicated_threshold: potato.dedicated_threshold * 1024,
+            preferred_dedicated_threshold: potato.preferred_dedicated_threshold * 1024,
+            transient_dedicated_threshold: potato.transient_dedicated_threshold * 1024,
+            starting_free_list_chunk: potato.starting_free_list_chunk * 1024,
+            final_free_list_chunk: potato.final_free_list_chunk * 1024,
+            minimal_buddy_size: potato.minimal_buddy_size * 1024,
+            initial_buddy_dedicated_size: potato.initial_buddy_dedicated_size * 1024,
+        }
+    }
+
+    /// Returns default configuration for average sized potato.
+    pub fn i_am_potato() -> Self {
+        Config {
+            dedicated_threshold: 32 * 1024,
+            preferred_dedicated_threshold: 1024,
+            transient_dedicated_threshold: 128 * 1024,
+            starting_free_list_chunk: 8 * 1024,
+            final_free_list_chunk: 128 * 1024,
+            minimal_buddy_size: 1,
+            initial_buddy_dedicated_size: 8 * 1024,
+        }
+    }
+}
diff --git a/third_party/rust/gpu-alloc/src/error.rs b/third_party/rust/gpu-alloc/src/error.rs
new file mode 100644
index 0000000000..95cde9bcaa
--- /dev/null
+++ b/third_party/rust/gpu-alloc/src/error.rs
@@ -0,0 +1,116 @@
+use {
+    core::fmt::{self, Display},
+    gpu_alloc_types::{DeviceMapError, OutOfMemory},
+};
+
+/// Enumeration of possible errors that may occur during memory allocation.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum AllocationError {
+    /// Backend reported that device memory has been exhausted.\
+    /// Deallocating device memory from the same heap may increase chance
+    /// that another allocation would succeed.
+    OutOfDeviceMemory,
+
+    /// Backend reported that host memory has been exhausted.\
+    /// Deallocating host memory may increase chance that another allocation would succeed.
+    OutOfHostMemory,
+
+    /// Allocation request cannot be fulfilled as no available memory types allowed
+    /// by `Request.memory_types` mask is compatible with `request.usage`.
+    NoCompatibleMemoryTypes,
+
+    /// Reached limit on allocated memory objects count.\
+    /// Deallocating device memory may increase chance that another allocation would succeed.
+    /// Especially dedicated memory blocks.
+    ///
+    /// If this error is returned when memory heaps are far from exhausted
+    /// `Config` should be tweaked to allocate larger memory objects.
+    TooManyObjects,
+}
+
+impl From<OutOfMemory> for AllocationError {
+    fn from(err: OutOfMemory) -> Self {
+        match err {
+            OutOfMemory::OutOfDeviceMemory => AllocationError::OutOfDeviceMemory,
+            OutOfMemory::OutOfHostMemory => AllocationError::OutOfHostMemory,
+        }
+    }
+}
+
+impl Display for AllocationError {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            AllocationError::OutOfDeviceMemory => fmt.write_str("Device memory exhausted"),
+            AllocationError::OutOfHostMemory => fmt.write_str("Host memory exhausted"),
+            AllocationError::NoCompatibleMemoryTypes => fmt.write_str(
+                "No compatible memory types from requested types support requested usage",
+            ),
+            AllocationError::TooManyObjects => {
+                fmt.write_str("Reached limit on allocated memory objects count")
+            }
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl std::error::Error for AllocationError {}
+
+/// Enumeration of possible errors that may occur during memory mapping.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum MapError {
+    /// Backend reported that device memory has been exhausted.\
+    /// Deallocating device memory from the same heap may increase chance
+    /// that another mapping would succeed.
+    OutOfDeviceMemory,
+
+    /// Backend reported that host memory has been exhausted.\
+    /// Deallocating host memory may increase chance that another mapping would succeed.
+    OutOfHostMemory,
+
+    /// Attempt to map memory block with non-host-visible memory type.\
+    /// Ensure to include `UsageFlags::HOST_ACCESS` into allocation request
+    /// when memory mapping is intended.
+    NonHostVisible,
+
+    /// Map failed for implementation specific reason.\
+    /// For Vulkan backend this includes failed attempt
+    /// to allocate large enough virtual address space.
+    MapFailed,
+
+    /// Mapping failed due to block being already mapped.
+    AlreadyMapped,
+}
+
+impl From<DeviceMapError> for MapError {
+    fn from(err: DeviceMapError) -> Self {
+        match err {
+            DeviceMapError::OutOfDeviceMemory => MapError::OutOfDeviceMemory,
+            DeviceMapError::OutOfHostMemory => MapError::OutOfHostMemory,
+            DeviceMapError::MapFailed => MapError::MapFailed,
+        }
+    }
+}
+
+impl From<OutOfMemory> for MapError {
+    fn from(err: OutOfMemory) -> Self {
+        match err {
+            OutOfMemory::OutOfDeviceMemory => MapError::OutOfDeviceMemory,
+            OutOfMemory::OutOfHostMemory => MapError::OutOfHostMemory,
+        }
+    }
+}
+
+impl Display for MapError {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            MapError::OutOfDeviceMemory => fmt.write_str("Device memory exhausted"),
+            MapError::OutOfHostMemory => fmt.write_str("Host memory exhausted"),
+            MapError::MapFailed => fmt.write_str("Failed to map memory object"),
+            MapError::NonHostVisible => fmt.write_str("Impossible to map non-host-visible memory"),
+            MapError::AlreadyMapped => fmt.write_str("Block is already mapped"),
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl std::error::Error for MapError {}
diff --git a/third_party/rust/gpu-alloc/src/freelist.rs b/third_party/rust/gpu-alloc/src/freelist.rs
new file mode 100644
index 0000000000..448a961d4f
--- /dev/null
+++ b/third_party/rust/gpu-alloc/src/freelist.rs
@@ -0,0 +1,528 @@
+use {
+    crate::{
+        align_down, align_up,
+        error::AllocationError,
+        heap::Heap,
+        util::{arc_unwrap, is_arc_unique},
+        MemoryBounds,
+    },
+    alloc::{sync::Arc, vec::Vec},
+    core::{cmp::Ordering, ptr::NonNull},
+    gpu_alloc_types::{AllocationFlags, DeviceMapError, MemoryDevice, MemoryPropertyFlags},
+};
+
+unsafe fn opt_ptr_add(ptr: Option<NonNull<u8>>, size: u64) -> Option<NonNull<u8>> {
+    ptr.map(|ptr| {
+        // Size is within memory region started at `ptr`.
+        // size is within `chunk_size` that fits `isize`.
+        NonNull::new_unchecked(ptr.as_ptr().offset(size as isize))
+    })
+}
+
+#[derive(Debug)]
+pub(super) struct FreeList<M> {
+    array: Vec<FreeListRegion<M>>,
+    counter: u64,
+}
+
+impl<M> FreeList<M> {
+    pub fn new() -> Self {
+        FreeList {
+            array: Vec::new(),
+            counter: 0,
+        }
+    }
+
+    pub fn get_block_from_new_memory(
+        &mut self,
+        memory: Arc<M>,
+        memory_size: u64,
+        ptr: Option<NonNull<u8>>,
+        align_mask: u64,
+        size: u64,
+    ) -> FreeListBlock<M> {
+        debug_assert!(size <= memory_size);
+
+        self.counter += 1;
+        self.array.push(FreeListRegion {
+            memory,
+            ptr,
+            chunk: self.counter,
+            start: 0,
+            end: memory_size,
+        });
+        self.get_block_at(self.array.len() - 1, align_mask, size)
+    }
+
+    pub fn get_block(&mut self, align_mask: u64, size: u64) -> Option<FreeListBlock<M>> {
+        let (index, _) = self.array.iter().enumerate().rev().find(|(_, region)| {
+            match region.end.checked_sub(size) {
+                Some(start) => {
+                    let aligned_start = align_down(start, align_mask);
+                    aligned_start >= region.start
+                }
+                None => false,
+            }
+        })?;
+
+        Some(self.get_block_at(index, align_mask, size))
+    }
+
+    fn get_block_at(&mut self, index: usize, align_mask: u64, size: u64) -> FreeListBlock<M> {
+        let region = &mut self.array[index];
+
+        let start = region.end - size;
+        let aligned_start = align_down(start, align_mask);
+
+        if aligned_start > region.start {
+            let block = FreeListBlock {
+                offset: aligned_start,
+                size: region.end - aligned_start,
+                chunk: region.chunk,
+                ptr: unsafe { opt_ptr_add(region.ptr, aligned_start - region.start) },
+                memory: region.memory.clone(),
+            };
+
+            region.end = aligned_start;
+
+            block
+        } else {
+            debug_assert_eq!(aligned_start, region.start);
+            let region = self.array.remove(index);
+            region.into_block()
+        }
+    }
+
+    pub fn insert_block(&mut self, block: FreeListBlock<M>) {
+        match self.array.binary_search_by(|b| b.cmp(&block)) {
+            Ok(_) => {
+                panic!("Overlapping block found in free list");
+            }
+            Err(index) if self.array.len() > index => match &mut self.array[..=index] {
+                [] => unreachable!(),
+                [next] => {
+                    debug_assert!(!next.is_suffix_block(&block));
+
+                    if next.is_prefix_block(&block) {
+                        next.merge_prefix_block(block);
+                    } else {
+                        self.array.insert(0, FreeListRegion::from_block(block));
+                    }
+                }
+                [.., prev, next] => {
+                    debug_assert!(!prev.is_prefix_block(&block));
+                    debug_assert!(!next.is_suffix_block(&block));
+
+                    if next.is_prefix_block(&block) {
+                        next.merge_prefix_block(block);
+
+                        if prev.consecutive(&*next) {
+                            let next = self.array.remove(index);
+                            let prev = &mut self.array[index - 1];
+                            prev.merge(next);
+                        }
+                    } else if prev.is_suffix_block(&block) {
+                        prev.merge_suffix_block(block);
+                    } else {
+                        self.array.insert(index, FreeListRegion::from_block(block));
+                    }
+                }
+            },
+            Err(_) => match &mut self.array[..] {
+                [] => self.array.push(FreeListRegion::from_block(block)),
+                [.., prev] => {
+                    debug_assert!(!prev.is_prefix_block(&block));
+                    if prev.is_suffix_block(&block) {
+                        prev.merge_suffix_block(block);
+                    } else {
+                        self.array.push(FreeListRegion::from_block(block));
+                    }
+                }
+            },
+        }
+    }
+
+    pub fn drain(&mut self, keep_last: bool) -> Option<impl Iterator<Item = (M, u64)> + '_> {
+        // Time to deallocate
+
+        let len = self.array.len();
+
+        let mut del = 0;
+        {
+            let regions = &mut self.array[..];
+
+            for i in 0..len {
+                if (i < len - 1 || !keep_last) && is_arc_unique(&mut regions[i].memory) {
+                    del += 1;
+                } else if del > 0 {
+                    regions.swap(i - del, i);
+                }
+            }
+        }
+
+        if del > 0 {
+            Some(self.array.drain(len - del..).map(move |region| {
+                debug_assert_eq!(region.start, 0);
+                (unsafe { arc_unwrap(region.memory) }, region.end)
+            }))
+        } else {
+            None
+        }
+    }
+}
+
+#[derive(Debug)]
+struct FreeListRegion<M> {
+    memory: Arc<M>,
+    ptr: Option<NonNull<u8>>,
+    chunk: u64,
+    start: u64,
+    end: u64,
+}
+
+unsafe impl<M> Sync for FreeListRegion<M> where M: Sync {}
+unsafe impl<M> Send for FreeListRegion<M> where M: Send {}
+
+impl<M> FreeListRegion<M> {
+    pub fn cmp(&self, block: &FreeListBlock<M>) -> Ordering {
+        debug_assert_eq!(
+            Arc::ptr_eq(&self.memory, &block.memory),
+            self.chunk == block.chunk
+        );
+
+        if self.chunk == block.chunk {
+            debug_assert_eq!(
+                Ord::cmp(&self.start, &block.offset),
+                Ord::cmp(&self.end, &(block.offset + block.size)),
+                "Free region {{ start: {}, end: {} }} overlaps with block {{ offset: {}, size: {} }}",
+                self.start,
+                self.end,
+                block.offset,
+                block.size,
+            );
+        }
+
+        Ord::cmp(&self.chunk, &block.chunk).then(Ord::cmp(&self.start, &block.offset))
+    }
+
+    fn from_block(block: FreeListBlock<M>) -> Self {
+        FreeListRegion {
+            memory: block.memory,
+            chunk: block.chunk,
+            ptr: block.ptr,
+            start: block.offset,
+            end: block.offset + block.size,
+        }
+    }
+
+    fn into_block(self) -> FreeListBlock<M> {
+        FreeListBlock {
+            memory: self.memory,
+            chunk: self.chunk,
+            ptr: self.ptr,
+            offset: self.start,
+            size: self.end - self.start,
+        }
+    }
+
+    fn consecutive(&self, other: &Self) -> bool {
+        if self.chunk != other.chunk {
+            return false;
+        }
+
+        debug_assert!(Arc::ptr_eq(&self.memory, &other.memory));
+
+        debug_assert_eq!(
+            Ord::cmp(&self.start, &other.start),
+            Ord::cmp(&self.end, &other.end)
+        );
+
+        self.end == other.start
+    }
+
+    fn merge(&mut self, next: FreeListRegion<M>) {
+        debug_assert!(self.consecutive(&next));
+        self.end = next.end;
+    }
+
+    fn is_prefix_block(&self, block: &FreeListBlock<M>) -> bool {
+        if self.chunk != block.chunk {
+            return false;
+        }
+
+        debug_assert!(Arc::ptr_eq(&self.memory, &block.memory));
+
+        debug_assert_eq!(
+            Ord::cmp(&self.start, &block.offset),
+            Ord::cmp(&self.end, &(block.offset + block.size))
+        );
+
+        self.start == (block.offset + block.size)
+    }
+
+    fn merge_prefix_block(&mut self, block: FreeListBlock<M>) {
+        debug_assert!(self.is_prefix_block(&block));
+        self.start = block.offset;
+        self.ptr = block.ptr;
+    }
+
+    fn is_suffix_block(&self, block: &FreeListBlock<M>) -> bool {
+        if self.chunk != block.chunk {
+            return false;
+        }
+
+        debug_assert!(Arc::ptr_eq(&self.memory, &block.memory));
+
+        debug_assert_eq!(
+            Ord::cmp(&self.start, &block.offset),
+            Ord::cmp(&self.end, &(block.offset + block.size))
+        );
+
+        self.end == block.offset
+    }
+
+    fn merge_suffix_block(&mut self, block: FreeListBlock<M>) {
+        debug_assert!(self.is_suffix_block(&block));
+        self.end += block.size;
+    }
+}
+
+#[derive(Debug)]
+pub struct FreeListBlock<M> {
+    pub memory: Arc<M>,
+    pub ptr: Option<NonNull<u8>>,
+    pub chunk: u64,
+    pub offset: u64,
+    pub size: u64,
+}
+
+unsafe impl<M> Sync for FreeListBlock<M> where M: Sync {}
+unsafe impl<M> Send for FreeListBlock<M> where M: Send {}
+
+#[derive(Debug)]
+pub(crate) struct FreeListAllocator<M> {
+    freelist: FreeList<M>,
+    chunk_size: u64,
+    final_chunk_size: u64,
+    memory_type: u32,
+    props: MemoryPropertyFlags,
+    atom_mask: u64,
+
+    total_allocations: u64,
+    total_deallocations: u64,
+}
+
+impl<M> Drop for FreeListAllocator<M> {
+    fn drop(&mut self) {
+        match Ord::cmp(&self.total_allocations, &self.total_deallocations) {
+            Ordering::Equal => {}
+            Ordering::Greater => {
+                report_error_on_drop!("Not all blocks were deallocated")
+            }
+            Ordering::Less => {
+                report_error_on_drop!("More blocks deallocated than allocated")
+            }
+        }
+
+        if !self.freelist.array.is_empty() {
+            report_error_on_drop!(
+                "FreeListAllocator has free blocks on drop. Allocator should be cleaned"
+            );
+        }
+    }
+}
+
+impl<M> FreeListAllocator<M>
+where
+    M: MemoryBounds + 'static,
+{
+    pub fn new(
+        starting_chunk_size: u64,
+        final_chunk_size: u64,
+        memory_type: u32,
+        props: MemoryPropertyFlags,
+        atom_mask: u64,
+    ) -> Self {
+        debug_assert_eq!(
+            align_down(starting_chunk_size, atom_mask),
+            starting_chunk_size
+        );
+
+        let starting_chunk_size = min(starting_chunk_size, isize::max_value());
+
+        debug_assert_eq!(align_down(final_chunk_size, atom_mask), final_chunk_size);
+        let final_chunk_size = min(final_chunk_size, isize::max_value());
+
+        FreeListAllocator {
+            freelist: FreeList::new(),
+            chunk_size: starting_chunk_size,
+            final_chunk_size,
+            memory_type,
+            props,
+            atom_mask,
+
+            total_allocations: 0,
+            total_deallocations: 0,
+        }
+    }
+
+    #[cfg_attr(feature = "tracing", tracing::instrument(skip(self, device)))]
+    pub unsafe fn alloc(
+        &mut self,
+        device: &impl MemoryDevice<M>,
+        size: u64,
+        align_mask: u64,
+        flags: AllocationFlags,
+        heap: &mut Heap,
+        allocations_remains: &mut u32,
+    ) -> Result<FreeListBlock<M>, AllocationError> {
+        debug_assert!(
+            self.final_chunk_size >= size,
+            "GpuAllocator must not request allocations equal or greater to chunks size"
+        );
+
+        let size = align_up(size, self.atom_mask).expect(
+            "Any value not greater than final chunk size (which is aligned) has to fit for alignment",
+        );
+
+        let align_mask = align_mask | self.atom_mask;
+        let host_visible = self.host_visible();
+
+        if size <= self.chunk_size {
+            // Otherwise there can't be any sufficiently large free blocks
+            if let Some(block) = self.freelist.get_block(align_mask, size) {
+                self.total_allocations += 1;
+                return Ok(block);
+            }
+        }
+
+        // New allocation is required.
+        if *allocations_remains == 0 {
+            return Err(AllocationError::TooManyObjects);
+        }
+
+        if size > self.chunk_size {
+            let multiple = (size - 1) / self.chunk_size + 1;
+            let multiple = multiple.next_power_of_two();
+
+            self.chunk_size = (self.chunk_size * multiple).min(self.final_chunk_size);
+        }
+
+        let mut memory = device.allocate_memory(self.chunk_size, self.memory_type, flags)?;
+        *allocations_remains -= 1;
+        heap.alloc(self.chunk_size);
+
+        // Map host visible allocations
+        let ptr = if host_visible {
+            match device.map_memory(&mut memory, 0, self.chunk_size) {
+                Ok(ptr) => Some(ptr),
+                Err(DeviceMapError::MapFailed) => {
+                    #[cfg(feature = "tracing")]
+                    tracing::error!("Failed to map host-visible memory in linear allocator");
+                    device.deallocate_memory(memory);
+                    *allocations_remains += 1;
+                    heap.dealloc(self.chunk_size);
+
+                    return Err(AllocationError::OutOfHostMemory);
+                }
+                Err(DeviceMapError::OutOfDeviceMemory) => {
+                    return Err(AllocationError::OutOfDeviceMemory);
+                }
+                Err(DeviceMapError::OutOfHostMemory) => {
+                    return Err(AllocationError::OutOfHostMemory);
+                }
+            }
+        } else {
+            None
+        };
+
+        let memory = Arc::new(memory);
+        let block =
+            self.freelist
+                .get_block_from_new_memory(memory, self.chunk_size, ptr, align_mask, size);
+
+        if self.chunk_size < self.final_chunk_size {
+            // Double next chunk size
+            // Limit to final value.
+            self.chunk_size = (self.chunk_size * 2).min(self.final_chunk_size);
+        }
+
+        self.total_allocations += 1;
+        Ok(block)
+    }
+
+    #[cfg_attr(feature = "tracing", tracing::instrument(skip(self, device)))]
+    pub unsafe fn dealloc(
+        &mut self,
+        device: &impl MemoryDevice<M>,
+        block: FreeListBlock<M>,
+        heap: &mut Heap,
+        allocations_remains: &mut u32,
+    ) {
+        debug_assert!(block.size < self.chunk_size);
+        debug_assert_ne!(block.size, 0);
+        self.freelist.insert_block(block);
+        self.total_deallocations += 1;
+
+        if let Some(memory) = self.freelist.drain(true) {
+            memory.for_each(|(memory, size)| {
+                device.deallocate_memory(memory);
+                *allocations_remains += 1;
+                heap.dealloc(size);
+            });
+        }
+    }
+
+    /// Deallocates leftover memory objects.
+    /// Should be used before dropping.
+    ///
+    /// # Safety
+    ///
+    /// * `device` must be one with `DeviceProperties` that were provided to create this `GpuAllocator` instance
+    /// * Same `device` instance must be used for all interactions with one `GpuAllocator` instance
+    ///   and memory blocks allocated from it
+    #[cfg_attr(feature = "tracing", tracing::instrument(skip(self, device)))]
+    pub unsafe fn cleanup(
+        &mut self,
+        device: &impl MemoryDevice<M>,
+        heap: &mut Heap,
+        allocations_remains: &mut u32,
+    ) {
+        if let Some(memory) = self.freelist.drain(false) {
+            memory.for_each(|(memory, size)| {
+                device.deallocate_memory(memory);
+                *allocations_remains += 1;
+                heap.dealloc(size);
+            });
+        }
+
+        #[cfg(feature = "tracing")]
+        {
+            if self.total_allocations == self.total_deallocations && !self.freelist.array.is_empty()
+            {
+                tracing::error!(
+                    "Some regions were not deallocated on cleanup, although all blocks are free.
+                        This is a bug in `FreeBlockAllocator`.
+                        See array of free blocks left:
+                        {:#?}",
+                    self.freelist.array,
+                );
+            }
+        }
+    }
+
+    fn host_visible(&self) -> bool {
+        self.props.contains(MemoryPropertyFlags::HOST_VISIBLE)
+    }
+}
+
+fn min<L, R>(l: L, r: R) -> L
+where
+    R: core::convert::TryInto<L>,
+    L: Ord,
+{
+    match r.try_into() {
+        Ok(r) => core::cmp::min(l, r),
+        Err(_) => l,
+    }
+}
diff --git a/third_party/rust/gpu-alloc/src/heap.rs b/third_party/rust/gpu-alloc/src/heap.rs
new file mode 100644
index 0000000000..fca7538919
--- /dev/null
+++ b/third_party/rust/gpu-alloc/src/heap.rs
@@ -0,0 +1,32 @@
+#[derive(Debug)]
+pub(crate) struct Heap {
+    size: u64,
+    used: u64,
+    allocated: u128,
+    deallocated: u128,
+}
+
+impl Heap {
+    pub(crate) fn new(size: u64) -> Self {
+        Heap {
+            size,
+            used: 0,
+            allocated: 0,
+            deallocated: 0,
+        }
+    }
+
+    pub(crate) fn size(&mut self) -> u64 {
+        self.size
+    }
+
+    pub(crate) fn alloc(&mut self, size: u64) {
+        self.used += size;
+        self.allocated += u128::from(size);
+    }
+
+    pub(crate) fn dealloc(&mut self, size: u64) {
+        self.used -= size;
+        self.deallocated += u128::from(size);
+    }
+}
diff --git a/third_party/rust/gpu-alloc/src/lib.rs b/third_party/rust/gpu-alloc/src/lib.rs
new file mode 100644
index 0000000000..97d04fac7a
--- /dev/null
+++ b/third_party/rust/gpu-alloc/src/lib.rs
@@ -0,0 +1,124 @@
+//!
+//! Implementation agnostic memory allocator for Vulkan like APIs.
+//!
+//! This crate is intended to be used as part of safe API implementations.\
+//! Use with caution. There are unsafe functions all over the place.
+//!
+//! # Usage
+//!
+//! Start with fetching `DeviceProperties` from `gpu-alloc-<backend>` crate for the backend of choice.\
+//! Then create `GpuAllocator` instance and use it for all device memory allocations.\
+//! `GpuAllocator` will take care for all necessary bookkeeping like memory object count limit,
+//! heap budget and memory mapping.
+//!
+//! ### Backends implementations
+//!
+//! Backend supporting crates should not depend on this crate.\
+//! Instead they should depend on `gpu-alloc-types` which is much more stable,
+//! allowing to upgrade `gpu-alloc` version without `gpu-alloc-<backend>` upgrade.
+//!
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+extern crate alloc;
+
+#[cfg(feature = "tracing")]
+macro_rules! report_error_on_drop {
+    ($($tokens:tt)*) => {{
+        #[cfg(feature = "std")]
+        {
+            if std::thread::panicking() {
+                return;
+            }
+        }
+
+        tracing::error!($($tokens)*)
+    }};
+}
+
+#[cfg(all(not(feature = "tracing"), feature = "std"))]
+macro_rules! report_error_on_drop {
+    ($($tokens:tt)*) => {{
+        if std::thread::panicking() {
+            return;
+        }
+        eprintln!($($tokens)*)
+    }};
+}
+
+#[cfg(all(not(feature = "tracing"), not(feature = "std")))]
+macro_rules! report_error_on_drop {
+    ($($tokens:tt)*) => {{
+        panic!($($tokens)*)
+    }};
+}
+
+mod allocator;
+mod block;
+mod buddy;
+mod config;
+mod error;
+mod freelist;
+mod heap;
+mod slab;
+mod usage;
+mod util;
+
+pub use {
+    self::{allocator::*, block::MemoryBlock, config::*, error::*, usage::*},
+    gpu_alloc_types::*,
+};
+
+/// Memory request for allocator.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub struct Request {
+    /// Minimal size of memory block required.
+    /// Returned block may have larger size,
+    /// use `MemoryBlock::size` to learn actual size of returned block.
+    pub size: u64,
+
+    /// Minimal alignment mask required.
+    /// Returned block may have larger alignment,
+    /// use `MemoryBlock::align` to learn actual alignment of returned block.
+    pub align_mask: u64,
+
+    /// Intended memory usage.
+    /// Returned block may support additional usages,
+    /// use `MemoryBlock::props` to learn memory properties of returned block.
+    pub usage: UsageFlags,
+
+    /// Bitset for memory types.
+    /// Returned block will be from memory type corresponding to one of set bits,
+    /// use `MemoryBlock::memory_type` to learn memory type index of returned block.
+    pub memory_types: u32,
+}
+
+/// Aligns `value` up to `align_mask`
+/// Returns smallest integer not lesser than `value` aligned by `align_mask`.
+/// Returns `None` on overflow.
+pub(crate) fn align_up(value: u64, align_mask: u64) -> Option<u64> {
+    Some(value.checked_add(align_mask)? & !align_mask)
+}
+
+/// Align `value` down to `align_mask`
+/// Returns largest integer not bigger than `value` aligned by `align_mask`.
+pub(crate) fn align_down(value: u64, align_mask: u64) -> u64 {
+    value & !align_mask
+}
+
+#[cfg(debug_assertions)]
+#[allow(unused_unsafe)]
+unsafe fn unreachable_unchecked() -> ! {
+    unreachable!()
+}
+
+#[cfg(not(debug_assertions))]
+unsafe fn unreachable_unchecked() -> ! {
+    core::hint::unreachable_unchecked()
+}
+
+// #[cfg(feature = "tracing")]
+use core::fmt::Debug as MemoryBounds;
+
+// #[cfg(not(feature = "tracing"))]
+// use core::any::Any as MemoryBounds;
diff --git a/third_party/rust/gpu-alloc/src/slab.rs b/third_party/rust/gpu-alloc/src/slab.rs
new file mode 100644
index 0000000000..b65c73e656
--- /dev/null
+++ b/third_party/rust/gpu-alloc/src/slab.rs
@@ -0,0 +1,97 @@
+use {crate::unreachable_unchecked, alloc::vec::Vec, core::mem::replace};
+
+#[derive(Debug)]
+enum Entry<T> {
+    Vacant(usize),
+    Occupied(T),
+}
+#[derive(Debug)]
+pub(crate) struct Slab<T> {
+    next_vacant: usize,
+    entries: Vec<Entry<T>>,
+}
+
+impl<T> Slab<T> {
+    pub fn new() -> Self {
+        Slab {
+            next_vacant: !0,
+            entries: Vec::new(),
+        }
+    }
+
+    /// Inserts value into this linked vec and returns index
+    /// at which value can be accessed in constant time.
+    pub fn insert(&mut self, value: T) -> usize {
+        if self.next_vacant >= self.entries.len() {
+            self.entries.push(Entry::Occupied(value));
+            self.entries.len() - 1
+        } else {
+            match *unsafe { self.entries.get_unchecked(self.next_vacant) } {
+                Entry::Vacant(next_vacant) => {
+                    unsafe {
+                        *self.entries.get_unchecked_mut(self.next_vacant) = Entry::Occupied(value);
+                    }
+                    replace(&mut self.next_vacant, next_vacant)
+                }
+                _ => unsafe { unreachable_unchecked() },
+            }
+        }
+    }
+
+    pub fn len(&self) -> usize {
+        self.entries.len()
+    }
+
+    pub unsafe fn get_unchecked(&self, index: usize) -> &T {
+        debug_assert!(index < self.len());
+
+        match self.entries.get_unchecked(index) {
+            Entry::Occupied(value) => value,
+            _ => unreachable_unchecked(),
+        }
+    }
+
+    pub unsafe fn get_unchecked_mut(&mut self, index: usize) -> &mut T {
+        debug_assert!(index < self.len());
+
+        match self.entries.get_unchecked_mut(index) {
+            Entry::Occupied(value) => value,
+            _ => unreachable_unchecked(),
+        }
+    }
+
+    pub fn get(&self, index: usize) -> &T {
+        match self.entries.get(index) {
+            Some(Entry::Occupied(value)) => value,
+            _ => panic!("Invalid index"),
+        }
+    }
+
+    pub fn get_mut(&mut self, index: usize) -> &mut T {
+        match self.entries.get_mut(index) {
+            Some(Entry::Occupied(value)) => value,
+            _ => panic!("Invalid index"),
+        }
+    }
+
+    pub unsafe fn remove_unchecked(&mut self, index: usize) -> T {
+        let entry = replace(
+            self.entries.get_unchecked_mut(index),
+            Entry::Vacant(self.next_vacant),
+        );
+
+        self.next_vacant = index;
+
+        match entry {
+            Entry::Occupied(value) => value,
+            _ => unreachable_unchecked(),
+        }
+    }
+
+    pub fn remove(&mut self, index: usize) -> T {
+        match self.entries.get_mut(index) {
+            Some(Entry::Occupied(_)) => unsafe { self.remove_unchecked(index) },
+            _ => panic!("Invalid index"),
+        }
+    }
+}
diff --git a/third_party/rust/gpu-alloc/src/usage.rs b/third_party/rust/gpu-alloc/src/usage.rs
new file mode 100644
index 0000000000..9834ef41c2
--- /dev/null
+++ b/third_party/rust/gpu-alloc/src/usage.rs
@@ -0,0 +1,167 @@
+use {
+    core::fmt::{self, Debug},
+    gpu_alloc_types::{MemoryPropertyFlags, MemoryType},
+};
+
+bitflags::bitflags! {
+    /// Memory usage type.
+    /// Bits set define intended usage for requested memory.
+    #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+    pub struct UsageFlags: u8 {
+        /// Hints for allocator to find memory with faster device access.
+        /// If no flags is specified than `FAST_DEVICE_ACCESS` is implied.
+        const FAST_DEVICE_ACCESS = 0x01;
+
+        /// Memory will be accessed from host.
+        /// This flags guarantees that host memory operations will be available.
+        /// Otherwise implementation is encouraged to use non-host-accessible memory.
+        const HOST_ACCESS = 0x02;
+
+        /// Hints allocator that memory will be used for data downloading.
+        /// Allocator will strongly prefer host-cached memory.
+        /// Implies `HOST_ACCESS` flag.
+        const DOWNLOAD = 0x04;
+
+        /// Hints allocator that memory will be used for data uploading.
+        /// If `DOWNLOAD` flag is not set then allocator will assume that
+        /// host will access memory in write-only manner and may
+        /// pick not host-cached.
+        /// Implies `HOST_ACCESS` flag.
+        const UPLOAD = 0x08;
+
+        /// Hints allocator that memory will be used for short duration
+        /// allowing to use faster algorithm with less memory overhead.
+        /// If use holds returned memory block for too long then
+        /// effective memory overhead increases instead.
+        /// Best use case is for staging buffer for single batch of operations.
+        const TRANSIENT = 0x10;
+
+        /// Requests memory that can be addressed with `u64`.
+        /// Allows fetching device address for resources bound to that memory.
+        const DEVICE_ADDRESS = 0x20;
+    }
+}
+
+#[derive(Clone, Copy, Debug)]
+struct MemoryForOneUsage {
+    mask: u32,
+    types: [u32; 32],
+    types_count: u32,
+}
+
+pub(crate) struct MemoryForUsage {
+    usages: [MemoryForOneUsage; 64],
+}
+
+impl Debug for MemoryForUsage {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt.debug_struct("MemoryForUsage")
+            .field("usages", &&self.usages[..])
+            .finish()
+    }
+}
+
+impl MemoryForUsage {
+    pub fn new(memory_types: &[MemoryType]) -> Self {
+        assert!(
+            memory_types.len() <= 32,
+            "Only up to 32 memory types supported"
+        );
+
+        let mut mfu = MemoryForUsage {
+            usages: [MemoryForOneUsage {
+                mask: 0,
+                types: [0; 32],
+                types_count: 0,
+            }; 64],
+        };
+
+        for usage in 0..64 {
+            mfu.usages[usage as usize] =
+                one_usage(UsageFlags::from_bits_truncate(usage), memory_types);
+        }
+
+        mfu
+    }
+
+    /// Returns mask with bits set for memory type indices that support the
+    /// usage.
+    pub fn mask(&self, usage: UsageFlags) -> u32 {
+        self.usages[usage.bits() as usize].mask
+    }
+
+    /// Returns slice of memory type indices that support the usage.
+    /// Earlier memory type has priority over later.
+    pub fn types(&self, usage: UsageFlags) -> &[u32] {
+        let usage = &self.usages[usage.bits() as usize];
+        &usage.types[..usage.types_count as usize]
+    }
+}
+
+fn one_usage(usage: UsageFlags, memory_types: &[MemoryType]) -> MemoryForOneUsage {
+    let mut types = [0; 32];
+    let mut types_count = 0;
+
+    for (index, mt) in memory_types.iter().enumerate() {
+        if compatible(usage, mt.props) {
+            types[types_count as usize] = index as u32;
+            types_count += 1;
+        }
+    }
+
+    types[..types_count as usize]
+        .sort_unstable_by_key(|&index| priority(usage, memory_types[index as usize].props));
+
+    let mask = types[..types_count as usize]
+        .iter()
+        .fold(0u32, |mask, index| mask | 1u32 << index);
+
+    MemoryForOneUsage {
+        mask,
+        types,
+        types_count,
+    }
+}
+
+fn compatible(usage: UsageFlags, flags: MemoryPropertyFlags) -> bool {
+    type Flags = MemoryPropertyFlags;
+    if flags.contains(Flags::LAZILY_ALLOCATED) || flags.contains(Flags::PROTECTED) {
+        // Unsupported
+        false
+    } else if usage.intersects(UsageFlags::HOST_ACCESS | UsageFlags::UPLOAD | UsageFlags::DOWNLOAD)
+    {
+        // Requires HOST_VISIBLE
+        flags.contains(Flags::HOST_VISIBLE)
+    } else {
+        true
+    }
+}
+
+/// Returns priority of memory with specified flags for specified usage.
+/// Lesser value returned = more prioritized.
+fn priority(usage: UsageFlags, flags: MemoryPropertyFlags) -> u32 {
+    type Flags = MemoryPropertyFlags;
+
+    // Highly prefer device local memory when `FAST_DEVICE_ACCESS` usage is specified
+    // or usage is empty.
+    let device_local: bool = flags.contains(Flags::DEVICE_LOCAL)
+        ^ (usage.is_empty() || usage.contains(UsageFlags::FAST_DEVICE_ACCESS));
+
+    assert!(
+        flags.contains(Flags::HOST_VISIBLE)
+            || !usage
+                .intersects(UsageFlags::HOST_ACCESS | UsageFlags::UPLOAD | UsageFlags::DOWNLOAD)
+    );
+
+    // Prefer cached memory for downloads.
+    // Or non-cached if downloads are not expected.
+    let cached: bool = flags.contains(Flags::HOST_CACHED) ^ usage.contains(UsageFlags::DOWNLOAD);
+
+    // Prefer coherent for both uploads and downloads.
+    // Prefer non-coherent if neither flags is set.
+    let coherent: bool = flags.contains(Flags::HOST_COHERENT)
+        ^ (usage.intersects(UsageFlags::UPLOAD | UsageFlags::DOWNLOAD));
+
+    // Each boolean is false if flags are preferred.
+    device_local as u32 * 4 + cached as u32 * 2 + coherent as u32
+}
diff --git a/third_party/rust/gpu-alloc/src/util.rs b/third_party/rust/gpu-alloc/src/util.rs
new file mode 100644
index 0000000000..f02259d958
--- /dev/null
+++ b/third_party/rust/gpu-alloc/src/util.rs
@@ -0,0 +1,44 @@
+use alloc::sync::Arc;
+
+/// Guarantees uniqueness only if `Weak` pointers are never created
+/// from this `Arc` or clones.
+pub(crate) fn is_arc_unique<M>(arc: &mut Arc<M>) -> bool {
+    let strong_count = Arc::strong_count(&*arc);
+    debug_assert_ne!(strong_count, 0, "This Arc should exist");
+
+    debug_assert!(
+        strong_count > 1 || Arc::get_mut(arc).is_some(),
+        "`Weak` pointer exists"
+    );
+
+    strong_count == 1
+}
+
+/// Can be used instead of `Arc::try_unwrap(arc).unwrap()`
+/// when it is guaranteed to succeed.
+pub(crate) unsafe fn arc_unwrap<M>(mut arc: Arc<M>) -> M {
+    use core::{mem::ManuallyDrop, ptr::read};
+    debug_assert!(is_arc_unique(&mut arc));
+
+    // Get raw pointer to inner value.
+    let raw = Arc::into_raw(arc);
+
+    // As `Arc` is unique and no Weak pointers exist
+    // it won't be dereferenced elsewhere.
+    let inner = read(raw);
+
+    // Cast to `ManuallyDrop` which guarantees to have same layout
+    // and will skip dropping.
+    drop(Arc::from_raw(raw as *const ManuallyDrop<M>));
+    inner
+}
+
+/// Can be used instead of `Arc::try_unwrap`
+/// only if `Weak` pointers are never created from this `Arc` or clones.
+pub(crate) unsafe fn try_arc_unwrap<M>(mut arc: Arc<M>) -> Option<M> {
+    if is_arc_unique(&mut arc) {
+        Some(arc_unwrap(arc))
+    } else {
+        None
+    }
+}