mmtk/plan/generational/
barrier.rs

1//! Generational read/write barrier implementations.
2
3use crate::plan::barriers::BarrierSemantics;
4use crate::plan::PlanTraceObject;
5use crate::plan::VectorQueue;
6use crate::policy::gc_work::DEFAULT_TRACE;
7use crate::scheduler::WorkBucketStage;
8use crate::util::*;
9use crate::vm::slot::MemorySlice;
10use crate::vm::VMBinding;
11use crate::MMTK;
12
13use super::gc_work::GenNurseryProcessEdges;
14use super::gc_work::ProcessModBuf;
15use super::gc_work::ProcessRegionModBuf;
16use super::global::GenerationalPlanExt;
17
18pub struct GenObjectBarrierSemantics<
19    VM: VMBinding,
20    P: GenerationalPlanExt<VM> + PlanTraceObject<VM>,
21> {
22    /// MMTk instance
23    mmtk: &'static MMTK<VM>,
24    /// Generational plan
25    plan: &'static P,
26    /// Object modbuf. Contains a list of objects that may contain pointers to the nursery space.
27    modbuf: VectorQueue<ObjectReference>,
28    /// Array-copy modbuf. Contains a list of sub-arrays or array slices that may contain pointers to the nursery space.
29    region_modbuf: VectorQueue<VM::VMMemorySlice>,
30}
31
32impl<VM: VMBinding, P: GenerationalPlanExt<VM> + PlanTraceObject<VM>>
33    GenObjectBarrierSemantics<VM, P>
34{
35    pub fn new(mmtk: &'static MMTK<VM>, plan: &'static P) -> Self {
36        Self {
37            mmtk,
38            plan,
39            modbuf: VectorQueue::new(),
40            region_modbuf: VectorQueue::new(),
41        }
42    }
43
44    fn flush_modbuf(&mut self) {
45        let buf = self.modbuf.take();
46        if !buf.is_empty() {
47            self.mmtk.scheduler.work_buckets[WorkBucketStage::Closure]
48                .add(ProcessModBuf::<GenNurseryProcessEdges<VM, P, DEFAULT_TRACE>>::new(buf));
49        }
50    }
51
52    fn flush_region_modbuf(&mut self) {
53        let buf = self.region_modbuf.take();
54        if !buf.is_empty() {
55            debug_assert!(!buf.is_empty());
56            self.mmtk.scheduler.work_buckets[WorkBucketStage::Closure].add(ProcessRegionModBuf::<
57                GenNurseryProcessEdges<VM, P, DEFAULT_TRACE>,
58            >::new(buf));
59        }
60    }
61}
62
63impl<VM: VMBinding, P: GenerationalPlanExt<VM> + PlanTraceObject<VM>> BarrierSemantics
64    for GenObjectBarrierSemantics<VM, P>
65{
66    type VM = VM;
67
68    fn flush(&mut self) {
69        self.flush_modbuf();
70        self.flush_region_modbuf();
71    }
72
73    fn object_reference_write_slow(
74        &mut self,
75        src: ObjectReference,
76        _slot: VM::VMSlot,
77        _target: Option<ObjectReference>,
78    ) {
79        // enqueue the object
80        self.modbuf.push(src);
81        self.modbuf.is_full().then(|| self.flush_modbuf());
82    }
83
84    fn memory_region_copy_slow(&mut self, _src: VM::VMMemorySlice, dst: VM::VMMemorySlice) {
85        // Check if the destination object/slice is in nursery space.
86        let dst_in_nursery = match dst.object() {
87            Some(obj) => self.plan.is_object_in_nursery(obj),
88            None => self.plan.is_address_in_nursery(dst.start()),
89        };
90        // Only enqueue array slices in mature spaces
91        if !dst_in_nursery {
92            // enqueue
93            self.region_modbuf.push(dst);
94            self.region_modbuf
95                .is_full()
96                .then(|| self.flush_region_modbuf());
97        }
98    }
99
100    fn object_probable_write_slow(&mut self, obj: ObjectReference) {
101        // enqueue the object
102        self.modbuf.push(obj);
103        self.modbuf.is_full().then(|| self.flush_modbuf());
104    }
105}
mmtk/plan/generational/barrier.rs

mmtk/plan/generational/
barrier.rs
