mmtk/util/alloc/
large_object_allocator.rs

1use std::sync::Arc;
2
3use crate::policy::largeobjectspace::LargeObjectSpace;
4use crate::policy::space::Space;
5use crate::util::alloc::{allocator, Allocator};
6use crate::util::opaque_pointer::*;
7use crate::util::Address;
8use crate::vm::VMBinding;
9
10use super::allocator::AllocatorContext;
11
12/// An allocator that only allocates at page granularity.
13/// This is intended for large objects.
14#[repr(C)]
15pub struct LargeObjectAllocator<VM: VMBinding> {
16    /// [`VMThread`] associated with this allocator instance
17    pub tls: VMThread,
18    /// [`Space`](src/policy/space/Space) instance associated with this allocator instance.
19    space: &'static LargeObjectSpace<VM>,
20    context: Arc<AllocatorContext<VM>>,
21}
22
23impl<VM: VMBinding> Allocator<VM> for LargeObjectAllocator<VM> {
24    fn get_tls(&self) -> VMThread {
25        self.tls
26    }
27
28    fn get_context(&self) -> &AllocatorContext<VM> {
29        &self.context
30    }
31
32    fn get_space(&self) -> &'static dyn Space<VM> {
33        // Casting the interior of the Option: from &LargeObjectSpace to &dyn Space
34        self.space as &'static dyn Space<VM>
35    }
36
37    fn does_thread_local_allocation(&self) -> bool {
38        false
39    }
40
41    fn alloc(&mut self, size: usize, align: usize, offset: usize) -> Address {
42        let cell: Address = self.alloc_slow(size, align, offset);
43        // We may get a null ptr from alloc due to the VM being OOM
44        if !cell.is_zero() {
45            allocator::align_allocation::<VM>(cell, align, offset)
46        } else {
47            cell
48        }
49    }
50
51    fn alloc_slow_once(&mut self, size: usize, align: usize, _offset: usize) -> Address {
52        if self.space.handle_obvious_oom_request(
53            self.tls,
54            size,
55            self.get_context().get_alloc_options(),
56        ) {
57            return Address::ZERO;
58        }
59
60        let maxbytes = allocator::get_maximum_aligned_size::<VM>(size, align);
61        let pages = crate::util::conversions::bytes_to_pages_up(maxbytes);
62        self.space
63            .allocate_pages(self.tls, pages, self.get_context().get_alloc_options())
64    }
65}
66
67impl<VM: VMBinding> LargeObjectAllocator<VM> {
68    pub(crate) fn new(
69        tls: VMThread,
70        space: &'static LargeObjectSpace<VM>,
71        context: Arc<AllocatorContext<VM>>,
72    ) -> Self {
73        LargeObjectAllocator {
74            tls,
75            space,
76            context,
77        }
78    }
79}
mmtk/util/alloc/large_object_allocator.rs

mmtk/util/alloc/
large_object_allocator.rs
