Struct mmtk::global_state::GlobalState

pub struct GlobalState {

    pub(crate) initialized: AtomicBool,
    pub(crate) gc_status: Mutex<GcStatus>,
    pub(crate) gc_start_time: AtomicRefCell<Option<Instant>>,
    pub(crate) emergency_collection: AtomicBool,
    pub(crate) user_triggered_collection: AtomicBool,
    pub(crate) internal_triggered_collection: AtomicBool,
    pub(crate) last_internal_triggered_collection: AtomicBool,
    pub(crate) allocation_success: AtomicBool,
    pub(crate) max_collection_attempts: AtomicUsize,
    pub(crate) cur_collection_attempts: AtomicUsize,
    pub(crate) scanned_stacks: AtomicUsize,
    pub(crate) stacks_prepared: AtomicBool,
    pub(crate) allocation_bytes: AtomicUsize,
    pub(crate) malloc_bytes: AtomicUsize,
    pub(crate) live_bytes_in_last_gc: AtomicUsize,
}

This stores some global states for an MMTK instance. Some MMTK components like plans and allocators may keep an reference to the struct, and can access it.

Fields

initialized: AtomicBool

Whether MMTk is now ready for collection. This is set to true when initialize_collection() is called.

gc_status: Mutex<GcStatus>

The current GC status.

gc_start_time: AtomicRefCell<Option<Instant>>

When did the last GC start? Only accessed by the last parked worker.

emergency_collection: AtomicBool

Is the current GC an emergency collection? Emergency means we may run out of memory soon, and we should attempt to collect as much as we can.

user_triggered_collection: AtomicBool

Is the current GC triggered by the user?

internal_triggered_collection: AtomicBool

Is the current GC triggered internally by MMTK? This is unused for now. We may have internally triggered GC for a concurrent plan.

last_internal_triggered_collection: AtomicBool

Is the last GC internally triggered?

allocation_success: AtomicBool

max_collection_attempts: AtomicUsize

cur_collection_attempts: AtomicUsize

scanned_stacks: AtomicUsize

A counter for per-mutator stack scanning

stacks_prepared: AtomicBool

Have we scanned all the stacks?

allocation_bytes: AtomicUsize

A counter that keeps tracks of the number of bytes allocated since last stress test

malloc_bytes: AtomicUsize

A counteer that keeps tracks of the number of bytes allocated by malloc

live_bytes_in_last_gc: AtomicUsize

This stores the size in bytes for all the live objects in last GC. This counter is only updated in the GC release phase.

Implementations

impl GlobalState

pub fn is_initialized(&self) -> bool

Is MMTk initialized?

pub fn set_collection_kind( &self, last_collection_was_exhaustive: bool, heap_can_grow: bool ) -> bool

Set the collection kind for the current GC. This is called before scheduling collection to determin what kind of collection it will be.

fn determine_collection_attempts(&self) -> usize

fn is_internal_triggered_collection(&self) -> bool

pub fn is_emergency_collection(&self) -> bool

pub fn is_user_triggered_collection(&self) -> bool

Return true if this collection was triggered by application code.

pub fn reset_collection_trigger(&self)

Reset collection state information.

pub fn stacks_prepared(&self) -> bool

Are the stacks scanned?

pub fn prepare_for_stack_scanning(&self)

Prepare for stack scanning. This is usually used with inform_stack_scanned(). This should be called before doing stack scanning.

pub fn inform_stack_scanned(&self, n_mutators: usize) -> bool

Inform that 1 stack has been scanned. The argument n_mutators indicates the total stacks we should scan. This method returns true if the number of scanned stacks equals the total mutator count. Otherwise it returns false. This method is thread safe and we guarantee only one thread will return true.

pub fn increase_allocation_bytes_by(&self, size: usize) -> usize

Increase the allocation bytes and return the current allocation bytes after increasing

pub fn get_malloc_bytes_in_pages(&self) -> usize

pub(crate) fn increase_malloc_bytes_by(&self, size: usize)

pub(crate) fn decrease_malloc_bytes_by(&self, size: usize)

pub fn get_live_bytes_in_last_gc(&self) -> usize

pub fn set_live_bytes_in_last_gc(&self, size: usize)

Trait Implementations

impl Default for GlobalState

fn default() -> Self

Returns the “default value” for a type.