Struct mmtk::util::alloc::bumpallocator::BumpAllocator

#[repr(C)]
pub struct BumpAllocator<VM: VMBinding> {
    pub tls: VMThread,
    pub bump_pointer: BumpPointer,
    space: &'static dyn Space<VM>,
    pub(super) context: Arc<AllocatorContext<VM>>,
}

A bump pointer allocator. It keeps a thread local allocation buffer, and bumps a cursor to allocate from the buffer.

Fields

tls: VMThread

VMThread associated with this allocator instance

bump_pointer: BumpPointer

Bump-pointer itself.

space: &'static dyn Space<VM>

Space instance associated with this allocator instance.

context: Arc<AllocatorContext<VM>>

Implementations

impl<VM: VMBinding> BumpAllocator<VM>

pub(crate) fn set_limit(&mut self, start: Address, limit: Address)

pub(crate) fn reset(&mut self)

pub(crate) fn rebind(&mut self, space: &'static dyn Space<VM>)

impl<VM: VMBinding> BumpAllocator<VM>

pub(crate) fn new( tls: VMThread, space: &'static dyn Space<VM>, context: Arc<AllocatorContext<VM>> ) -> Self

fn acquire_block( &mut self, size: usize, align: usize, offset: usize, stress_test: bool ) -> Address

Trait Implementations

impl<VM: VMBinding> Allocator<VM> for BumpAllocator<VM>

fn alloc_slow_once_precise_stress( &mut self, size: usize, align: usize, offset: usize, need_poll: bool ) -> Address

Slow path for allocation if precise stress testing has been enabled. It works by manipulating the limit to be always below the cursor. Can have three different cases:

• acquires a new block if the hard limit has been met;
• allocates an object using the bump pointer semantics from the fastpath if there is sufficient space; and
• does not allocate an object but forces a poll for GC if the stress factor has been crossed.

fn get_space(&self) -> &'static dyn Space<VM>

Return the Space instance associated with this allocator instance.

fn get_context(&self) -> &AllocatorContext<VM>

Return the context for the allocator.

fn does_thread_local_allocation(&self) -> bool

Return if this allocator can do thread local allocation. If an allocator does not do thread local allocation, each allocation will go to slowpath and will have a check for GC polls.

fn get_thread_local_buffer_granularity(&self) -> usize

Return at which granularity the allocator acquires memory from the global space and use them as thread local buffer. For example, the BumpAllocator acquires memory at 32KB blocks. Depending on the actual size for the current object, they always acquire memory of N*32KB (N>=1). Thus the BumpAllocator returns 32KB for this method. Only allocators that do thread local allocation need to implement this method.

fn alloc(&mut self, size: usize, align: usize, offset: usize) -> Address

An allocation attempt. The implementation of this function depends on the allocator used. If an allocator supports thread local allocations, then the allocation will be serviced from its TLAB, otherwise it will default to using the slowpath, i.e. alloc_slow.

fn alloc_slow_once( &mut self, size: usize, align: usize, offset: usize ) -> Address

Single slow path allocation attempt. This is called by alloc_slow_inline. The implementation of this function depends on the allocator used. Generally, if an allocator supports thread local allocations, it will try to allocate more TLAB space here. If it doesn’t, then (generally) the allocator simply allocates enough space for the current object.

fn get_tls(&self) -> VMThread

Return the VMThread associated with this allocator instance.

fn alloc_slow(&mut self, size: usize, align: usize, offset: usize) -> Address

Slowpath allocation attempt. This function is explicitly not inlined for performance considerations.

fn alloc_slow_inline( &mut self, size: usize, align: usize, offset: usize ) -> Address

Slowpath allocation attempt. This function executes the actual slowpath allocation. A slowpath allocation in MMTk attempts to allocate the object using the per-allocator definition of alloc_slow_once. This function also accounts for increasing the allocation bytes in order to support stress testing. In case precise stress testing is being used, the alloc_slow_once_precise_stress function is used instead.

fn alloc_slow_once_traced( &mut self, size: usize, align: usize, offset: usize ) -> Address

A wrapper method for alloc_slow_once to insert USDT tracepoints.

fn on_mutator_destroy(&mut self)

The crate::plan::Mutator that includes this allocator is going to be destroyed. Some allocators may need to save/transfer its thread local data to the space.