qiurui
/
asterinas
mirror of https://github.com/asterinas/asterinas.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Use 64-bit reference counts for frames and fix meta layouts

This commit is contained in:
Zhang Junyang 2025-01-06 13:59:51 +08:00 committed by Tate, Hongliang Tian
parent 44d54f4b23
commit b59cd9cea2
2 changed files with 9 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
ostd/src/mm/frame/meta.rs
View File

@ -44,7 +44,7 @@ use core::{
fmt::Debug,
mem::{size_of, MaybeUninit},
result::Result,
sync::atomic::{AtomicU32, Ordering},
sync::atomic::{AtomicU64, Ordering},
};
use align_ext::AlignExt;
@ -64,9 +64,9 @@ use crate::{
/// The maximum number of bytes of the metadata of a frame.
pub const FRAME_METADATA_MAX_SIZE: usize =
META_SLOT_SIZE - size_of::<bool>() - size_of::<AtomicU32>() - size_of::<FrameMetaVtablePtr>();
META_SLOT_SIZE - size_of::<AtomicU64>() - size_of::<FrameMetaVtablePtr>();
/// The maximum alignment in bytes of the metadata of a frame.
pub const FRAME_METADATA_MAX_ALIGN: usize = align_of::<MetaSlot>();
pub const FRAME_METADATA_MAX_ALIGN: usize = META_SLOT_SIZE;
const META_SLOT_SIZE: usize = 64;
@ -102,14 +102,14 @@ pub(in crate::mm) struct MetaSlot {
//
// Other than this field the fields should be `MaybeUninit`.
// See initialization in `alloc_meta_frames`.
pub(super) ref_count: AtomicU32,
pub(super) ref_count: AtomicU64,
/// The virtual table that indicates the type of the metadata.
pub(super) vtable_ptr: UnsafeCell<MaybeUninit<FrameMetaVtablePtr>>,
}
pub(super) const REF_COUNT_UNUSED: u32 = u32::MAX;
pub(super) const REF_COUNT_UNIQUE: u32 = u32::MAX - 1;
pub(super) const REF_COUNT_MAX: u32 = i32::MAX as u32;
pub(super) const REF_COUNT_UNUSED: u64 = u64::MAX;
pub(super) const REF_COUNT_UNIQUE: u64 = u64::MAX - 1;
pub(super) const REF_COUNT_MAX: u64 = i64::MAX as u64;
type FrameMetaVtablePtr = core::ptr::DynMetadata<dyn AnyFrameMeta>;
@ -498,7 +498,7 @@ fn alloc_meta_frames(tot_nr_frames: usize) -> (usize, Paddr) {
let slots = paddr_to_vaddr(start_paddr) as *mut MetaSlot;
// Fill the metadata frames with a byte pattern of `REF_COUNT_UNUSED`.
debug_assert_eq!(REF_COUNT_UNUSED.to_ne_bytes(), [0xff, 0xff, 0xff, 0xff]);
debug_assert_eq!(REF_COUNT_UNUSED.to_ne_bytes(), [0xff; 8]);
// SAFETY: `slots` and the length is a valid region for the metadata frames
// that are going to be treated as metadata slots. The byte pattern is
// valid as the initial value of the reference count (other fields are

2
ostd/src/mm/frame/mod.rs
View File

@ -148,7 +148,7 @@ impl<M: AnyFrameMeta + ?Sized> Frame<M> {
/// The function is safe to call, but using it requires extra care. The
/// reference count can be changed by other threads at any time including
/// potentially between calling this method and acting on the result.
pub fn reference_count(&self) -> u32 {
pub fn reference_count(&self) -> u64 {
let refcnt = self.slot().ref_count.load(Ordering::Relaxed);
debug_assert!(refcnt < meta::REF_COUNT_MAX);
refcnt