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use super::*;
use crate::util::constants::{BYTES_IN_PAGE, BYTES_IN_WORD, LOG_BITS_IN_BYTE};
use crate::util::conversions::raw_align_up;
use crate::util::heap::layout::vm_layout::BYTES_IN_CHUNK;
use crate::util::memory;
use crate::util::metadata::metadata_val_traits::*;
#[cfg(feature = "vo_bit")]
use crate::util::metadata::vo_bit::VO_BIT_SIDE_METADATA_SPEC;
use crate::util::Address;
use num_traits::FromPrimitive;
use ranges::BitByteRange;
use std::fmt;
use std::io::Result;
use std::sync::atomic::{AtomicU8, Ordering};
/// This struct stores the specification of a side metadata bit-set.
/// It is used as an input to the (inline) functions provided by the side metadata module.
///
/// Each plan or policy which uses a metadata bit-set, needs to create an instance of this struct.
///
/// For performance reasons, objects of this struct should be constants.
#[derive(Clone, Copy, PartialEq, Eq, Hash)]
pub struct SideMetadataSpec {
/// The name for this side metadata.
pub name: &'static str,
/// Is this side metadata global? Local metadata is used by certain spaces,
/// while global metadata is used by all the spaces.
pub is_global: bool,
/// The offset for this side metadata.
pub offset: SideMetadataOffset,
/// Number of bits needed per region. E.g. 0 = 1 bit, 1 = 2 bit.
pub log_num_of_bits: usize,
/// Number of bytes of the region. E.g. 3 = 8 bytes, 12 = 4096 bytes (page).
pub log_bytes_in_region: usize,
}
impl SideMetadataSpec {
/// Is this spec using contiguous side metadata? If not, it uses chunked side metadata.
pub const fn uses_contiguous_side_metadata(&self) -> bool {
self.is_global || cfg!(target_pointer_width = "64")
}
/// Is offset for this spec Address?
pub const fn is_absolute_offset(&self) -> bool {
self.uses_contiguous_side_metadata()
}
/// If offset for this spec relative? (chunked side metadata for local specs in 32 bits)
pub const fn is_rel_offset(&self) -> bool {
!self.is_absolute_offset()
}
/// Get the absolute offset for the spec.
pub const fn get_absolute_offset(&self) -> Address {
debug_assert!(self.is_absolute_offset());
unsafe { self.offset.addr }
}
/// Get the relative offset for the spec.
pub const fn get_rel_offset(&self) -> usize {
debug_assert!(self.is_rel_offset());
unsafe { self.offset.rel_offset }
}
/// Return the upperbound offset for the side metadata. The next side metadata should be laid out at this offset.
#[cfg(target_pointer_width = "64")]
pub const fn upper_bound_offset(&self) -> SideMetadataOffset {
debug_assert!(self.is_absolute_offset());
SideMetadataOffset {
addr: unsafe { self.offset.addr }
.add(crate::util::metadata::side_metadata::metadata_address_range_size(self)),
}
}
/// Return the upperbound offset for the side metadata. The next side metadata should be laid out at this offset.
#[cfg(target_pointer_width = "32")]
pub const fn upper_bound_offset(&self) -> SideMetadataOffset {
if self.is_absolute_offset() {
SideMetadataOffset {
addr: unsafe { self.offset.addr }
.add(crate::util::metadata::side_metadata::metadata_address_range_size(self)),
}
} else {
SideMetadataOffset {
rel_offset: unsafe { self.offset.rel_offset }
+ crate::util::metadata::side_metadata::metadata_bytes_per_chunk(
self.log_bytes_in_region,
self.log_num_of_bits,
),
}
}
}
/// The upper bound address for metadata address computed for this global spec. The computed metadata address
/// should never be larger than this address. Otherwise, we are accessing the metadata that is laid out
/// after this spec. This spec must be a contiguous side metadata spec (which uses address
/// as offset).
pub const fn upper_bound_address_for_contiguous(&self) -> Address {
debug_assert!(self.is_absolute_offset());
unsafe { self.upper_bound_offset().addr }
}
/// The upper bound address for metadata address computed for this global spec. The computed metadata address
/// should never be larger than this address. Otherwise, we are accessing the metadata that is laid out
/// after this spec. This spec must be a chunked side metadata spec (which uses relative offset). Only 32 bit local
/// side metadata uses chunked metadata.
#[cfg(target_pointer_width = "32")]
pub const fn upper_bound_address_for_chunked(&self, data_addr: Address) -> Address {
debug_assert!(self.is_rel_offset());
address_to_meta_chunk_addr(data_addr).add(unsafe { self.upper_bound_offset().rel_offset })
}
/// Used only for debugging.
/// This panics if the required metadata is not mapped
#[cfg(debug_assertions)]
pub(crate) fn assert_metadata_mapped(&self, data_addr: Address) {
let meta_start = address_to_meta_address(self, data_addr).align_down(BYTES_IN_PAGE);
trace!(
"ensure_metadata_is_mapped({}).meta_start({})",
data_addr,
meta_start
);
memory::panic_if_unmapped(meta_start, BYTES_IN_PAGE);
}
/// Used only for debugging.
/// * Assert if the given MetadataValue type matches the spec.
/// * Assert if the provided value is valid in the spec.
#[cfg(debug_assertions)]
fn assert_value_type<T: MetadataValue>(&self, val: Option<T>) {
let log_b = self.log_num_of_bits;
match log_b {
_ if log_b < 3 => {
assert_eq!(T::LOG2, 3);
if let Some(v) = val {
assert!(
v.to_u8().unwrap() < (1 << (1 << log_b)),
"Input value {:?} is invalid for the spec {:?}",
v,
self
);
}
}
3..=6 => assert_eq!(T::LOG2, log_b as u32),
_ => unreachable!("side metadata > {}-bits is not supported", 1 << log_b),
}
}
/// Check with the mmapper to see if side metadata is mapped for the spec for the data address.
pub(crate) fn is_mapped(&self, data_addr: Address) -> bool {
use crate::MMAPPER;
let meta_addr = address_to_meta_address(self, data_addr);
MMAPPER.is_mapped_address(meta_addr)
}
/// This method is used for bulk zeroing side metadata for a data address range.
pub(crate) fn zero_meta_bits(
meta_start_addr: Address,
meta_start_bit: u8,
meta_end_addr: Address,
meta_end_bit: u8,
) {
let mut visitor = |range| {
match range {
BitByteRange::Bytes { start, end } => {
memory::zero(start, end - start);
false
}
BitByteRange::BitsInByte {
addr,
bit_start,
bit_end,
} => {
// we are zeroing selected bit in one byte
// Get a mask that the bits we need to zero are set to zero, and the other bits are 1.
let mask: u8 =
u8::MAX.checked_shl(bit_end as u32).unwrap_or(0) | !(u8::MAX << bit_start);
unsafe { addr.as_ref::<AtomicU8>() }.fetch_and(mask, Ordering::SeqCst);
false
}
}
};
ranges::break_bit_range(
meta_start_addr,
meta_start_bit,
meta_end_addr,
meta_end_bit,
true,
&mut visitor,
);
}
/// This method is used for bulk setting side metadata for a data address range.
pub(crate) fn set_meta_bits(
meta_start_addr: Address,
meta_start_bit: u8,
meta_end_addr: Address,
meta_end_bit: u8,
) {
let mut visitor = |range| {
match range {
BitByteRange::Bytes { start, end } => {
memory::set(start, 0xff, end - start);
false
}
BitByteRange::BitsInByte {
addr,
bit_start,
bit_end,
} => {
// we are setting selected bits in one byte
// Get a mask that the bits we need to set are 1, and the other bits are 0.
let mask: u8 = !(u8::MAX.checked_shl(bit_end as u32).unwrap_or(0))
& (u8::MAX << bit_start);
unsafe { addr.as_ref::<AtomicU8>() }.fetch_or(mask, Ordering::SeqCst);
false
}
}
};
ranges::break_bit_range(
meta_start_addr,
meta_start_bit,
meta_end_addr,
meta_end_bit,
true,
&mut visitor,
);
}
/// This method does bulk update for the given data range. It calculates the metadata bits for the given data range,
/// and invoke the given method to update the metadata bits.
pub(super) fn bulk_update_metadata(
&self,
start: Address,
size: usize,
update_meta_bits: &impl Fn(Address, u8, Address, u8),
) {
// Update bits for a contiguous side metadata spec. We can simply calculate the data end address, and
// calculate the metadata address for the data end.
let update_contiguous = |data_start: Address, data_bytes: usize| {
if data_bytes == 0 {
return;
}
let meta_start = address_to_meta_address(self, data_start);
let meta_start_shift = meta_byte_lshift(self, data_start);
let meta_end = address_to_meta_address(self, data_start + data_bytes);
let meta_end_shift = meta_byte_lshift(self, data_start + data_bytes);
update_meta_bits(meta_start, meta_start_shift, meta_end, meta_end_shift);
};
// Update bits for a discontiguous side metadata spec (chunked metadata). The side metadata for different
// chunks are stored in discontiguous memory. For example, Chunk #2 follows Chunk #1, but the side metadata
// for Chunk #2 does not immediately follow the side metadata for Chunk #1. So when we bulk update metadata for Chunk #1,
// we cannot update up to the metadata address for the Chunk #2 start. Otherwise it may modify unrelated metadata
// between the two chunks' metadata.
// Instead, we compute how many bytes/bits we need to update.
// The data for which the metadata will be updates has to be in the same chunk.
#[cfg(target_pointer_width = "32")]
let update_discontiguous = |data_start: Address, data_bytes: usize| {
use crate::util::constants::BITS_IN_BYTE;
if data_bytes == 0 {
return;
}
debug_assert_eq!(
data_start.align_down(BYTES_IN_CHUNK),
(data_start + data_bytes - 1).align_down(BYTES_IN_CHUNK),
"The data to be zeroed in discontiguous specs needs to be in the same chunk"
);
let meta_start = address_to_meta_address(self, data_start);
let meta_start_shift = meta_byte_lshift(self, data_start);
// How many bits we need to zero for data_bytes
let meta_total_bits = (data_bytes >> self.log_bytes_in_region) << self.log_num_of_bits;
let meta_delta_bytes = meta_total_bits >> LOG_BITS_IN_BYTE;
let meta_delta_bits: u8 = (meta_total_bits % BITS_IN_BYTE) as u8;
// Calculate the end byte/addr and end bit
let (meta_end, meta_end_shift) = {
let mut end_addr = meta_start + meta_delta_bytes;
let mut end_bit = meta_start_shift + meta_delta_bits;
if end_bit >= BITS_IN_BYTE as u8 {
end_bit -= BITS_IN_BYTE as u8;
end_addr += 1usize;
}
(end_addr, end_bit)
};
update_meta_bits(meta_start, meta_start_shift, meta_end, meta_end_shift);
};
if cfg!(target_pointer_width = "64") || self.is_global {
update_contiguous(start, size);
}
#[cfg(target_pointer_width = "32")]
if !self.is_global {
// per chunk policy-specific metadata for 32-bits targets
let chunk_num = ((start + size).align_down(BYTES_IN_CHUNK)
- start.align_down(BYTES_IN_CHUNK))
/ BYTES_IN_CHUNK;
if chunk_num == 0 {
update_discontiguous(start, size);
} else {
let second_data_chunk = start.align_up(BYTES_IN_CHUNK);
// bzero the first sub-chunk
update_discontiguous(start, second_data_chunk - start);
let last_data_chunk = (start + size).align_down(BYTES_IN_CHUNK);
// bzero the last sub-chunk
update_discontiguous(last_data_chunk, start + size - last_data_chunk);
let mut next_data_chunk = second_data_chunk;
// bzero all chunks in the middle
while next_data_chunk != last_data_chunk {
update_discontiguous(next_data_chunk, BYTES_IN_CHUNK);
next_data_chunk += BYTES_IN_CHUNK;
}
}
}
}
/// Bulk-zero a specific metadata for a memory region. Note that this method is more sophisiticated than a simple memset, especially in the following
/// cases:
/// * the metadata for the range includes partial bytes (a few bits in the same byte).
/// * for 32 bits local side metadata, the side metadata is stored in discontiguous chunks, we will have to bulk zero for each chunk's side metadata.
///
/// # Arguments
///
/// * `start`: The starting address of a memory region. The side metadata starting from this data address will be zeroed.
/// * `size`: The size of the memory region.
pub fn bzero_metadata(&self, start: Address, size: usize) {
#[cfg(feature = "extreme_assertions")]
let _lock = sanity::SANITY_LOCK.lock().unwrap();
#[cfg(feature = "extreme_assertions")]
sanity::verify_bzero(self, start, size);
self.bulk_update_metadata(start, size, &Self::zero_meta_bits)
}
/// Bulk set a specific metadata for a memory region. Note that this method is more sophisiticated than a simple memset, especially in the following
/// cases:
/// * the metadata for the range includes partial bytes (a few bits in the same byte).
/// * for 32 bits local side metadata, the side metadata is stored in discontiguous chunks, we will have to bulk set for each chunk's side metadata.
///
/// # Arguments
///
/// * `start`: The starting address of a memory region. The side metadata starting from this data address will be set to all 1s in the bits.
/// * `size`: The size of the memory region.
pub fn bset_metadata(&self, start: Address, size: usize) {
#[cfg(feature = "extreme_assertions")]
let _lock = sanity::SANITY_LOCK.lock().unwrap();
#[cfg(feature = "extreme_assertions")]
sanity::verify_bset(self, start, size);
self.bulk_update_metadata(start, size, &Self::set_meta_bits)
}
/// Bulk copy the `other` side metadata for a memory region to this side metadata.
///
/// This function only works for contiguous metadata.
/// Curently all global metadata are contiguous.
/// It also requires the other metadata to have the same number of bits per region
/// and the same region size.
///
/// # Arguments
///
/// * `start`: The starting address of a memory region.
/// * `size`: The size of the memory region.
/// * `other`: The other metadata to copy from.
pub fn bcopy_metadata_contiguous(&self, start: Address, size: usize, other: &SideMetadataSpec) {
#[cfg(feature = "extreme_assertions")]
let _lock = sanity::SANITY_LOCK.lock().unwrap();
#[cfg(feature = "extreme_assertions")]
sanity::verify_bcopy(self, start, size, other);
debug_assert_eq!(other.log_bytes_in_region, self.log_bytes_in_region);
debug_assert_eq!(other.log_num_of_bits, self.log_num_of_bits);
let dst_meta_start_addr = address_to_meta_address(self, start);
let dst_meta_start_bit = meta_byte_lshift(self, start);
let dst_meta_end_addr = address_to_meta_address(self, start + size);
let dst_meta_end_bit = meta_byte_lshift(self, start + size);
let src_meta_start_addr = address_to_meta_address(other, start);
let src_meta_start_bit = meta_byte_lshift(other, start);
debug_assert_eq!(dst_meta_start_bit, src_meta_start_bit);
let mut visitor = |range| {
match range {
BitByteRange::Bytes {
start: dst_start,
end: dst_end,
} => unsafe {
let byte_offset = dst_start - dst_meta_start_addr;
let src_start = src_meta_start_addr + byte_offset;
let size = dst_end - dst_start;
std::ptr::copy::<u8>(src_start.to_ptr(), dst_start.to_mut_ptr(), size);
false
},
BitByteRange::BitsInByte {
addr: dst,
bit_start,
bit_end,
} => {
let byte_offset = dst - dst_meta_start_addr;
let src = src_meta_start_addr + byte_offset;
// we are setting selected bits in one byte
let mask: u8 = !(u8::MAX.checked_shl(bit_end as u32).unwrap_or(0))
& (u8::MAX << bit_start); // Get a mask that the bits we need to set are 1, and the other bits are 0.
let old_src = unsafe { src.as_ref::<AtomicU8>() }.load(Ordering::Relaxed);
let old_dst = unsafe { dst.as_ref::<AtomicU8>() }.load(Ordering::Relaxed);
let new = (old_src & mask) | (old_dst & !mask);
unsafe { dst.as_ref::<AtomicU8>() }.store(new, Ordering::Relaxed);
false
}
}
};
ranges::break_bit_range(
dst_meta_start_addr,
dst_meta_start_bit,
dst_meta_end_addr,
dst_meta_end_bit,
true,
&mut visitor,
);
}
/// This is a wrapper method for implementing side metadata access. It does nothing other than
/// calling the access function with no overhead, but in debug builds,
/// it includes multiple checks to make sure the access is sane.
/// * check whether the given value type matches the number of bits for the side metadata.
/// * check if the side metadata memory is mapped.
/// * check if the side metadata content is correct based on a sanity map (only for extreme assertions).
#[allow(unused_variables)] // data_addr/input is not used in release build
fn side_metadata_access<
const CHECK_VALUE: bool,
T: MetadataValue,
R: Copy,
F: FnOnce() -> R,
V: FnOnce(R),
>(
&self,
data_addr: Address,
input: Option<T>,
access_func: F,
verify_func: V,
) -> R {
// With extreme assertions, we maintain a sanity table for each side metadata access. For whatever we store in
// side metadata, we store in the sanity table. So we can use that table to check if its results are conssitent
// with the actual side metadata.
// To achieve this, we need to apply a lock when we access side metadata. This will hide some concurrency bugs,
// but makes it possible for us to assert our side metadata implementation is correct.
#[cfg(feature = "extreme_assertions")]
let _lock = sanity::SANITY_LOCK.lock().unwrap();
// A few checks
#[cfg(debug_assertions)]
{
if CHECK_VALUE {
self.assert_value_type::<T>(input);
}
#[cfg(feature = "extreme_assertions")]
self.assert_metadata_mapped(data_addr);
}
// Actual access to the side metadata
let ret = access_func();
// Verifying the side metadata: checks the result with the sanity table, or store some results to the sanity table
if CHECK_VALUE {
verify_func(ret);
}
ret
}
/// Non-atomic load of metadata.
///
/// # Safety
///
/// This is unsafe because:
///
/// 1. Concurrent access to this operation is undefined behaviour.
/// 2. Interleaving Non-atomic and atomic operations is undefined behaviour.
pub unsafe fn load<T: MetadataValue>(&self, data_addr: Address) -> T {
self.side_metadata_access::<true, T, _, _, _>(
data_addr,
None,
|| {
let meta_addr = address_to_meta_address(self, data_addr);
let bits_num_log = self.log_num_of_bits;
if bits_num_log < 3 {
let lshift = meta_byte_lshift(self, data_addr);
let mask = meta_byte_mask(self) << lshift;
let byte_val = meta_addr.load::<u8>();
FromPrimitive::from_u8((byte_val & mask) >> lshift).unwrap()
} else {
meta_addr.load::<T>()
}
},
|_v| {
#[cfg(feature = "extreme_assertions")]
sanity::verify_load(self, data_addr, _v);
},
)
}
/// Non-atomic store of metadata.
///
/// # Safety
///
/// This is unsafe because:
///
/// 1. Concurrent access to this operation is undefined behaviour.
/// 2. Interleaving Non-atomic and atomic operations is undefined behaviour.
pub unsafe fn store<T: MetadataValue>(&self, data_addr: Address, metadata: T) {
self.side_metadata_access::<true, T, _, _, _>(
data_addr,
Some(metadata),
|| {
let meta_addr = address_to_meta_address(self, data_addr);
let bits_num_log = self.log_num_of_bits;
if bits_num_log < 3 {
let lshift = meta_byte_lshift(self, data_addr);
let mask = meta_byte_mask(self) << lshift;
let old_val = meta_addr.load::<u8>();
let new_val = (old_val & !mask) | (metadata.to_u8().unwrap() << lshift);
meta_addr.store::<u8>(new_val);
} else {
meta_addr.store::<T>(metadata);
}
},
|_| {
#[cfg(feature = "extreme_assertions")]
sanity::verify_store(self, data_addr, metadata);
},
)
}
/// Loads a value from the side metadata for the given address.
/// This method has similar semantics to `store` in Rust atomics.
pub fn load_atomic<T: MetadataValue>(&self, data_addr: Address, order: Ordering) -> T {
self.side_metadata_access::<true, T, _, _, _>(
data_addr,
None,
|| {
let meta_addr = address_to_meta_address(self, data_addr);
let bits_num_log = self.log_num_of_bits;
if bits_num_log < 3 {
let lshift = meta_byte_lshift(self, data_addr);
let mask = meta_byte_mask(self) << lshift;
let byte_val = unsafe { meta_addr.atomic_load::<AtomicU8>(order) };
FromPrimitive::from_u8((byte_val & mask) >> lshift).unwrap()
} else {
unsafe { T::load_atomic(meta_addr, order) }
}
},
|_v| {
#[cfg(feature = "extreme_assertions")]
sanity::verify_load(self, data_addr, _v);
},
)
}
/// Store the given value to the side metadata for the given address.
/// This method has similar semantics to `store` in Rust atomics.
pub fn store_atomic<T: MetadataValue>(&self, data_addr: Address, metadata: T, order: Ordering) {
self.side_metadata_access::<true, T, _, _, _>(
data_addr,
Some(metadata),
|| {
let meta_addr = address_to_meta_address(self, data_addr);
let bits_num_log = self.log_num_of_bits;
if bits_num_log < 3 {
let lshift = meta_byte_lshift(self, data_addr);
let mask = meta_byte_mask(self) << lshift;
let metadata_u8 = metadata.to_u8().unwrap();
let _ = unsafe {
<u8 as MetadataValue>::fetch_update(meta_addr, order, order, |v: u8| {
Some((v & !mask) | (metadata_u8 << lshift))
})
};
} else {
unsafe {
T::store_atomic(meta_addr, metadata, order);
}
}
},
|_| {
#[cfg(feature = "extreme_assertions")]
sanity::verify_store(self, data_addr, metadata);
},
)
}
/// Non-atomically store zero to the side metadata for the given address.
/// This method mainly facilitates clearing multiple metadata specs for the same address in a loop.
///
/// # Safety
///
/// This is unsafe because:
///
/// 1. Concurrent access to this operation is undefined behaviour.
/// 2. Interleaving Non-atomic and atomic operations is undefined behaviour.
pub unsafe fn set_zero(&self, data_addr: Address) {
use num_traits::Zero;
match self.log_num_of_bits {
0..=3 => self.store(data_addr, u8::zero()),
4 => self.store(data_addr, u16::zero()),
5 => self.store(data_addr, u32::zero()),
6 => self.store(data_addr, u64::zero()),
_ => unreachable!(),
}
}
/// Atomiccally store zero to the side metadata for the given address.
/// This method mainly facilitates clearing multiple metadata specs for the same address in a loop.
pub fn set_zero_atomic(&self, data_addr: Address, order: Ordering) {
use num_traits::Zero;
match self.log_num_of_bits {
0..=3 => self.store_atomic(data_addr, u8::zero(), order),
4 => self.store_atomic(data_addr, u16::zero(), order),
5 => self.store_atomic(data_addr, u32::zero(), order),
6 => self.store_atomic(data_addr, u64::zero(), order),
_ => unreachable!(),
}
}
/// Atomically store one to the side metadata for the data address with the _possible_ side effect of corrupting
/// and setting the entire byte in the side metadata to 0xff. This can only be used for side metadata smaller
/// than a byte.
/// This means it does not only set the side metadata for the data address, and it may also have a side effect of
/// corrupting and setting the side metadata for the adjacent data addresses. This method is only intended to be
/// used as an optimization to skip masking and setting bits in some scenarios where setting adjancent bits to 1 is benign.
///
/// # Safety
/// This method _may_ corrupt and set adjacent bits in the side metadata as a side effect. The user must
/// make sure that this behavior is correct and must not rely on the side effect of this method to set bits.
pub unsafe fn set_raw_byte_atomic(&self, data_addr: Address, order: Ordering) {
debug_assert!(self.log_num_of_bits < 3);
cfg_if::cfg_if! {
if #[cfg(feature = "extreme_assertions")] {
// For extreme assertions, we only set 1 to the given address.
self.store_atomic::<u8>(data_addr, 1, order)
} else {
self.side_metadata_access::<false, u8, _, _, _>(
data_addr,
Some(1u8),
|| {
let meta_addr = address_to_meta_address(self, data_addr);
u8::store_atomic(meta_addr, 0xffu8, order);
},
|_| {}
)
}
}
}
/// Load the raw byte in the side metadata byte that is mapped to the data address.
///
/// # Safety
/// This is unsafe because:
///
/// 1. Concurrent access to this operation is undefined behaviour.
/// 2. Interleaving Non-atomic and atomic operations is undefined behaviour.
pub unsafe fn load_raw_byte(&self, data_addr: Address) -> u8 {
debug_assert!(self.log_num_of_bits < 3);
self.side_metadata_access::<false, u8, _, _, _>(
data_addr,
None,
|| {
let meta_addr = address_to_meta_address(self, data_addr);
meta_addr.load::<u8>()
},
|_| {},
)
}
/// Load the raw word that includes the side metadata byte mapped to the data address.
///
/// # Safety
/// This is unsafe because:
///
/// 1. Concurrent access to this operation is undefined behaviour.
/// 2. Interleaving Non-atomic and atomic operations is undefined behaviour.
pub unsafe fn load_raw_word(&self, data_addr: Address) -> usize {
use crate::util::constants::*;
debug_assert!(self.log_num_of_bits < (LOG_BITS_IN_BYTE + LOG_BYTES_IN_ADDRESS) as usize);
self.side_metadata_access::<false, usize, _, _, _>(
data_addr,
None,
|| {
let meta_addr = address_to_meta_address(self, data_addr);
let aligned_meta_addr = meta_addr.align_down(BYTES_IN_ADDRESS);
aligned_meta_addr.load::<usize>()
},
|_| {},
)
}
/// Stores the new value into the side metadata for the gien address if the current value is the same as the old value.
/// This method has similar semantics to `compare_exchange` in Rust atomics.
/// The return value is a result indicating whether the new value was written and containing the previous value.
/// On success this value is guaranteed to be equal to current.
pub fn compare_exchange_atomic<T: MetadataValue>(
&self,
data_addr: Address,
old_metadata: T,
new_metadata: T,
success_order: Ordering,
failure_order: Ordering,
) -> std::result::Result<T, T> {
self.side_metadata_access::<true, T, _, _, _>(
data_addr,
Some(new_metadata),
|| {
let meta_addr = address_to_meta_address(self, data_addr);
let bits_num_log = self.log_num_of_bits;
if bits_num_log < 3 {
let lshift = meta_byte_lshift(self, data_addr);
let mask = meta_byte_mask(self) << lshift;
let real_old_byte = unsafe { meta_addr.atomic_load::<AtomicU8>(success_order) };
let expected_old_byte =
(real_old_byte & !mask) | ((old_metadata.to_u8().unwrap()) << lshift);
let expected_new_byte =
(expected_old_byte & !mask) | ((new_metadata.to_u8().unwrap()) << lshift);
unsafe {
meta_addr.compare_exchange::<AtomicU8>(
expected_old_byte,
expected_new_byte,
success_order,
failure_order,
)
}
.map(|x| FromPrimitive::from_u8((x & mask) >> lshift).unwrap())
.map_err(|x| FromPrimitive::from_u8((x & mask) >> lshift).unwrap())
} else {
unsafe {
T::compare_exchange(
meta_addr,
old_metadata,
new_metadata,
success_order,
failure_order,
)
}
}
},
|_res| {
#[cfg(feature = "extreme_assertions")]
if _res.is_ok() {
sanity::verify_store(self, data_addr, new_metadata);
}
},
)
}
/// This is used to implement fetch_add/sub for bits.
/// For fetch_and/or, we don't necessarily need this method. We could directly do fetch_and/or on the u8.
fn fetch_ops_on_bits<F: Fn(u8) -> u8>(
&self,
data_addr: Address,
meta_addr: Address,
set_order: Ordering,
fetch_order: Ordering,
update: F,
) -> u8 {
let lshift = meta_byte_lshift(self, data_addr);
let mask = meta_byte_mask(self) << lshift;
let old_raw_byte = unsafe {
<u8 as MetadataValue>::fetch_update(
meta_addr,
set_order,
fetch_order,
|raw_byte: u8| {
let old_val = (raw_byte & mask) >> lshift;
let new_val = update(old_val);
let new_raw_byte = (raw_byte & !mask) | ((new_val << lshift) & mask);
Some(new_raw_byte)
},
)
}
.unwrap();
(old_raw_byte & mask) >> lshift
}
/// Adds the value to the current value for this side metadata for the given address.
/// This method has similar semantics to `fetch_add` in Rust atomics.
/// Returns the previous value.
pub fn fetch_add_atomic<T: MetadataValue>(
&self,
data_addr: Address,
val: T,
order: Ordering,
) -> T {
self.side_metadata_access::<true, T, _, _, _>(
data_addr,
Some(val),
|| {
let meta_addr = address_to_meta_address(self, data_addr);
let bits_num_log = self.log_num_of_bits;
if bits_num_log < 3 {
FromPrimitive::from_u8(self.fetch_ops_on_bits(
data_addr,
meta_addr,
order,
order,
|x: u8| x.wrapping_add(val.to_u8().unwrap()),
))
.unwrap()
} else {
unsafe { T::fetch_add(meta_addr, val, order) }
}
},
|_old_val| {
#[cfg(feature = "extreme_assertions")]
sanity::verify_update::<T>(self, data_addr, _old_val, _old_val.wrapping_add(&val))
},
)
}
/// Subtracts the value from the current value for this side metadata for the given address.
/// This method has similar semantics to `fetch_sub` in Rust atomics.
/// Returns the previous value.
pub fn fetch_sub_atomic<T: MetadataValue>(
&self,
data_addr: Address,
val: T,
order: Ordering,
) -> T {
self.side_metadata_access::<true, T, _, _, _>(
data_addr,
Some(val),
|| {
let meta_addr = address_to_meta_address(self, data_addr);
if self.log_num_of_bits < 3 {
FromPrimitive::from_u8(self.fetch_ops_on_bits(
data_addr,
meta_addr,
order,
order,
|x: u8| x.wrapping_sub(val.to_u8().unwrap()),
))
.unwrap()
} else {
unsafe { T::fetch_sub(meta_addr, val, order) }
}
},
|_old_val| {
#[cfg(feature = "extreme_assertions")]
sanity::verify_update::<T>(self, data_addr, _old_val, _old_val.wrapping_sub(&val))
},
)
}
/// Bitwise 'and' the value with the current value for this side metadata for the given address.
/// This method has similar semantics to `fetch_and` in Rust atomics.
/// Returns the previous value.
pub fn fetch_and_atomic<T: MetadataValue>(
&self,
data_addr: Address,
val: T,
order: Ordering,
) -> T {
self.side_metadata_access::<true, T, _, _, _>(
data_addr,
Some(val),
|| {
let meta_addr = address_to_meta_address(self, data_addr);
if self.log_num_of_bits < 3 {
let lshift = meta_byte_lshift(self, data_addr);
let mask = meta_byte_mask(self) << lshift;
// We do not need to use fetch_ops_on_bits(), we can just set irrelavent bits to 1, and do fetch_and
let rhs = (val.to_u8().unwrap() << lshift) | !mask;
let old_raw_byte =
unsafe { <u8 as MetadataValue>::fetch_and(meta_addr, rhs, order) };
let old_val = (old_raw_byte & mask) >> lshift;
FromPrimitive::from_u8(old_val).unwrap()
} else {
unsafe { T::fetch_and(meta_addr, val, order) }
}
},
|_old_val| {
#[cfg(feature = "extreme_assertions")]
sanity::verify_update::<T>(self, data_addr, _old_val, _old_val.bitand(val))
},
)
}
/// Bitwise 'or' the value with the current value for this side metadata for the given address.
/// This method has similar semantics to `fetch_or` in Rust atomics.
/// Returns the previous value.
pub fn fetch_or_atomic<T: MetadataValue>(
&self,
data_addr: Address,
val: T,
order: Ordering,
) -> T {
self.side_metadata_access::<true, T, _, _, _>(
data_addr,
Some(val),
|| {
let meta_addr = address_to_meta_address(self, data_addr);
if self.log_num_of_bits < 3 {
let lshift = meta_byte_lshift(self, data_addr);
let mask = meta_byte_mask(self) << lshift;
// We do not need to use fetch_ops_on_bits(), we can just set irrelavent bits to 0, and do fetch_or
let rhs = (val.to_u8().unwrap() << lshift) & mask;
let old_raw_byte =
unsafe { <u8 as MetadataValue>::fetch_or(meta_addr, rhs, order) };
let old_val = (old_raw_byte & mask) >> lshift;
FromPrimitive::from_u8(old_val).unwrap()
} else {
unsafe { T::fetch_or(meta_addr, val, order) }
}
},
|_old_val| {
#[cfg(feature = "extreme_assertions")]
sanity::verify_update::<T>(self, data_addr, _old_val, _old_val.bitor(val))
},
)
}
/// Fetches the value for this side metadata for the given address, and applies a function to it that returns an optional new value.
/// This method has similar semantics to `fetch_update` in Rust atomics.
/// Returns a Result of Ok(previous_value) if the function returned Some(_), else Err(previous_value).
pub fn fetch_update_atomic<T: MetadataValue, F: FnMut(T) -> Option<T> + Copy>(
&self,
data_addr: Address,
set_order: Ordering,
fetch_order: Ordering,
mut f: F,
) -> std::result::Result<T, T> {
self.side_metadata_access::<true, T, _, _, _>(
data_addr,
None,
move || -> std::result::Result<T, T> {
let meta_addr = address_to_meta_address(self, data_addr);
if self.log_num_of_bits < 3 {
let lshift = meta_byte_lshift(self, data_addr);
let mask = meta_byte_mask(self) << lshift;
unsafe {
<u8 as MetadataValue>::fetch_update(
meta_addr,
set_order,
fetch_order,
|raw_byte: u8| {
let old_val = (raw_byte & mask) >> lshift;
f(FromPrimitive::from_u8(old_val).unwrap()).map(|new_val| {
(raw_byte & !mask)
| ((new_val.to_u8().unwrap() << lshift) & mask)
})
},
)
}
.map(|x| FromPrimitive::from_u8((x & mask) >> lshift).unwrap())
.map_err(|x| FromPrimitive::from_u8((x & mask) >> lshift).unwrap())
} else {
unsafe { T::fetch_update(meta_addr, set_order, fetch_order, f) }
}
},
|_result| {
#[cfg(feature = "extreme_assertions")]
if let Ok(old_val) = _result {
sanity::verify_update::<T>(self, data_addr, old_val, f(old_val).unwrap())
}
},
)
}
/// Search for a data address that has a non zero value in the side metadata. The search starts from the given data address (including this address),
/// and iterates backwards for the given bytes (non inclusive) before the data address.
///
/// The data_addr and the corresponding side metadata address may not be mapped. Thus when this function checks the given data address, and
/// when it searches back, it needs to check if the address is mapped or not to avoid loading from an unmapped address.
///
/// This function returns an address that is aligned to the region of this side metadata (`log_bytes_per_region`), and the side metadata
/// for the address is non zero.
///
/// # Safety
///
/// This function uses non-atomic load for the side metadata. The user needs to make sure
/// that there is no other thread that is mutating the side metadata.
#[allow(clippy::let_and_return)]
pub unsafe fn find_prev_non_zero_value<T: MetadataValue>(
&self,
data_addr: Address,
search_limit_bytes: usize,
) -> Option<Address> {
debug_assert!(search_limit_bytes > 0);
if self.uses_contiguous_side_metadata() {
// Contiguous side metadata
let result = self.find_prev_non_zero_value_fast::<T>(data_addr, search_limit_bytes);
#[cfg(debug_assertions)]
{
// Double check if the implementation is correct
let result2 =
self.find_prev_non_zero_value_simple::<T>(data_addr, search_limit_bytes);
assert_eq!(result, result2, "find_prev_non_zero_value_fast returned a diffrent result from the naive implementation.");
}
result
} else {
// TODO: We should be able to optimize further for this case. However, we need to be careful that the side metadata
// is not contiguous, and we need to skip to the next chunk's side metadata when we search to a different chunk.
// This won't be used for VO bit, as VO bit is global and is always contiguous. So for now, I am not bothered to do it.
warn!("We are trying to search non zero bits in an discontiguous side metadata. The performance is slow, as MMTk does not optimize for this case.");
self.find_prev_non_zero_value_simple::<T>(data_addr, search_limit_bytes)
}
}
fn find_prev_non_zero_value_simple<T: MetadataValue>(
&self,
data_addr: Address,
search_limit_bytes: usize,
) -> Option<Address> {
let region_bytes = 1 << self.log_bytes_in_region;
// Figure out the range that we need to search.
let start_addr = data_addr.align_down(region_bytes);
let end_addr = data_addr.saturating_sub(search_limit_bytes) + 1usize;
let mut cursor = start_addr;
while cursor >= end_addr {
// We encounter an unmapped address. Just return None.
if !cursor.is_mapped() {
return None;
}
// If we find non-zero value, just return it.
if !unsafe { self.load::<T>(cursor).is_zero() } {
return Some(cursor);
}
cursor -= region_bytes;
}
None
}
#[allow(clippy::let_and_return)]
fn find_prev_non_zero_value_fast<T: MetadataValue>(
&self,
data_addr: Address,
search_limit_bytes: usize,
) -> Option<Address> {
debug_assert!(self.uses_contiguous_side_metadata());
// Quick check if the data address is mapped at all.
if !data_addr.is_mapped() {
return None;
}
// Quick check if the current data_addr has a non zero value.
if !unsafe { self.load::<T>(data_addr).is_zero() } {
return Some(data_addr.align_down(1 << self.log_bytes_in_region));
}
// Figure out the start and end data address.
let start_addr = data_addr.saturating_sub(search_limit_bytes) + 1usize;
let end_addr = data_addr;
// Then figure out the start and end metadata address and bits.
// The start bit may not be accurate, as we map any address in the region to the same bit.
// We will filter the result at the end to make sure the found address is in the search range.
let start_meta_addr = address_to_contiguous_meta_address(self, start_addr);
let start_meta_shift = meta_byte_lshift(self, start_addr);
let end_meta_addr = address_to_contiguous_meta_address(self, end_addr);
let end_meta_shift = meta_byte_lshift(self, end_addr);
let mut res = None;
let mut visitor = |range: BitByteRange| {
match range {
BitByteRange::Bytes { start, end } => {
match helpers::find_last_non_zero_bit_in_metadata_bytes(start, end) {
helpers::FindMetaBitResult::Found { addr, bit } => {
let (addr, bit) = align_metadata_address(self, addr, bit);
res = Some(contiguous_meta_address_to_address(self, addr, bit));
// Return true to abort the search. We found the bit.
true
}
// If we see unmapped metadata, we don't need to search any more.
helpers::FindMetaBitResult::UnmappedMetadata => true,
// Return false to continue searching.
helpers::FindMetaBitResult::NotFound => false,
}
}
BitByteRange::BitsInByte {
addr,
bit_start,
bit_end,
} => {
match helpers::find_last_non_zero_bit_in_metadata_bits(addr, bit_start, bit_end)
{
helpers::FindMetaBitResult::Found { addr, bit } => {
let (addr, bit) = align_metadata_address(self, addr, bit);
res = Some(contiguous_meta_address_to_address(self, addr, bit));
// Return true to abort the search. We found the bit.
true
}
// If we see unmapped metadata, we don't need to search any more.
helpers::FindMetaBitResult::UnmappedMetadata => true,
// Return false to continue searching.
helpers::FindMetaBitResult::NotFound => false,
}
}
}
};
ranges::break_bit_range(
start_meta_addr,
start_meta_shift,
end_meta_addr,
end_meta_shift,
false,
&mut visitor,
);
// We have to filter the result. We search between [start_addr, end_addr). But we actually
// search with metadata bits. It is possible the metadata bit for start_addr is the same bit
// as an address that is before start_addr. E.g. 0x2010f026360 and 0x2010f026361 are mapped
// to the same bit, 0x2010f026361 is the start address and 0x2010f026360 is outside the search range.
res.map(|addr| addr.align_down(1 << self.log_bytes_in_region))
.filter(|addr| *addr >= start_addr && *addr < end_addr)
}
/// Search for data addresses that have non zero values in the side metadata. This method is
/// primarily used for heap traversal by scanning the VO bits.
///
/// This function searches the side metadata for the data address range from `data_start_addr`
/// (inclusive) to `data_end_addr` (exclusive). The data address range must be fully mapped.
///
/// For each data region that has non-zero side metadata, `visit_data` is called with the lowest
/// address of that region. Note that it may not be the original address used to set the
/// metadata bits.
pub fn scan_non_zero_values<T: MetadataValue>(
&self,
data_start_addr: Address,
data_end_addr: Address,
visit_data: &mut impl FnMut(Address),
) {
if self.uses_contiguous_side_metadata() && self.log_num_of_bits == 0 {
// Contiguous one-bit-per-region side metadata
// TODO: VO bits is one-bit-per-word. But if we want to scan other metadata (such as
// the forwarding bits which has two bits per word), we will need to refactor the
// algorithm of `scan_non_zero_values_fast`.
self.scan_non_zero_values_fast(data_start_addr, data_end_addr, visit_data);
} else {
// TODO: VO bits are always contiguous. But if we want to scan other metadata, such as
// side mark bits, we need to refactor `bulk_update_metadata` to support `FnMut`, too,
// and use it to apply `scan_non_zero_values_fast` on each contiguous side metadata
// range.
warn!(
"We are trying to search for non zero bits in a discontiguous side metadata \
or the metadata has more than one bit per region. \
The performance is slow, as MMTk does not optimize for this case."
);
self.scan_non_zero_values_simple::<T>(data_start_addr, data_end_addr, visit_data);
}
}
fn scan_non_zero_values_simple<T: MetadataValue>(
&self,
data_start_addr: Address,
data_end_addr: Address,
visit_data: &mut impl FnMut(Address),
) {
let region_bytes = 1usize << self.log_bytes_in_region;
let mut cursor = data_start_addr;
while cursor < data_end_addr {
debug_assert!(cursor.is_mapped());
// If we find non-zero value, just call back.
if !unsafe { self.load::<T>(cursor).is_zero() } {
visit_data(cursor);
}
cursor += region_bytes;
}
}
fn scan_non_zero_values_fast(
&self,
data_start_addr: Address,
data_end_addr: Address,
visit_data: &mut impl FnMut(Address),
) {
debug_assert!(self.uses_contiguous_side_metadata());
debug_assert_eq!(self.log_num_of_bits, 0);
// Then figure out the start and end metadata address and bits.
let start_meta_addr = address_to_contiguous_meta_address(self, data_start_addr);
let start_meta_shift = meta_byte_lshift(self, data_start_addr);
let end_meta_addr = address_to_contiguous_meta_address(self, data_end_addr);
let end_meta_shift = meta_byte_lshift(self, data_end_addr);
let mut visitor = |range| {
match range {
BitByteRange::Bytes { start, end } => {
helpers::scan_non_zero_bits_in_metadata_bytes(start, end, &mut |addr, bit| {
visit_data(helpers::contiguous_meta_address_to_address(self, addr, bit));
});
}
BitByteRange::BitsInByte {
addr,
bit_start,
bit_end,
} => helpers::scan_non_zero_bits_in_metadata_bits(
addr,
bit_start,
bit_end,
&mut |addr, bit| {
visit_data(helpers::contiguous_meta_address_to_address(self, addr, bit));
},
),
}
false
};
ranges::break_bit_range(
start_meta_addr,
start_meta_shift,
end_meta_addr,
end_meta_shift,
false,
&mut visitor,
);
}
}
impl fmt::Debug for SideMetadataSpec {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_fmt(format_args!(
"SideMetadataSpec {} {{ \
**is_global: {:?} \
**offset: {} \
**log_num_of_bits: 0x{:x} \
**log_bytes_in_region: 0x{:x} \
}}",
self.name,
self.is_global,
unsafe {
if self.is_absolute_offset() {
format!("0x{:x}", self.offset.addr)
} else {
format!("0x{:x}", self.offset.rel_offset)
}
},
self.log_num_of_bits,
self.log_bytes_in_region
))
}
}
/// A union of Address or relative offset (usize) used to store offset for a side metadata spec.
/// If a spec is contiguous side metadata, it uses address. Othrewise it uses usize.
// The fields are made private on purpose. They can only be accessed from SideMetadata which knows whether it is Address or usize.
#[derive(Clone, Copy)]
pub union SideMetadataOffset {
addr: Address,
rel_offset: usize,
}
impl SideMetadataOffset {
/// Get an offset for a fixed address. This is usually used to set offset for the first spec (subsequent ones can be laid out with `layout_after`).
pub const fn addr(addr: Address) -> Self {
SideMetadataOffset { addr }
}
/// Get an offset for a relative offset (usize). This is usually used to set offset for the first spec (subsequent ones can be laid out with `layout_after`).
pub const fn rel(rel_offset: usize) -> Self {
SideMetadataOffset { rel_offset }
}
/// Get an offset after a spec. This is used to layout another spec immediately after this one.
pub const fn layout_after(spec: &SideMetadataSpec) -> SideMetadataOffset {
// Some metadata may be so small that its size is not a multiple of byte size. One example
// is `CHUNK_MARK`. It is one byte per chunk. However, on 32-bit architectures, we
// allocate side metadata per chunk. In that case, it will only occupy one byte. If we
// do not align the upper bound offset up, subsequent local metadata that need to be
// accessed at, for example, word granularity will be misaligned.
// TODO: Currently we align metadata to word size so that it is safe to access the metadata
// one word at a time. In the future, we may allow each metadata to specify its own
// alignment requirement.
let upper_bound_offset = spec.upper_bound_offset();
if spec.is_absolute_offset() {
let addr = unsafe { upper_bound_offset.addr };
let aligned_addr = addr.align_up(BYTES_IN_WORD);
SideMetadataOffset::addr(aligned_addr)
} else {
let rel_offset = unsafe { upper_bound_offset.rel_offset };
let aligned_rel_offset = raw_align_up(rel_offset, BYTES_IN_WORD);
SideMetadataOffset::rel(aligned_rel_offset)
}
}
}
// Address and usize has the same layout, so we use usize for implementing these traits.
impl PartialEq for SideMetadataOffset {
fn eq(&self, other: &Self) -> bool {
unsafe { self.rel_offset == other.rel_offset }
}
}
impl Eq for SideMetadataOffset {}
impl std::hash::Hash for SideMetadataOffset {
fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
unsafe { self.rel_offset }.hash(state);
}
}
/// This struct stores all the side metadata specs for a policy. Generally a policy needs to know its own
/// side metadata spec as well as the plan's specs.
pub(crate) struct SideMetadataContext {
// For plans
pub global: Vec<SideMetadataSpec>,
// For policies
pub local: Vec<SideMetadataSpec>,
}
impl SideMetadataContext {
#[allow(clippy::vec_init_then_push)] // allow this, as we conditionally push based on features.
pub fn new_global_specs(specs: &[SideMetadataSpec]) -> Vec<SideMetadataSpec> {
let mut ret = vec![];
#[cfg(feature = "vo_bit")]
ret.push(VO_BIT_SIDE_METADATA_SPEC);
if let Some(spec) = crate::mmtk::SFT_MAP.get_side_metadata() {
if spec.is_global {
ret.push(*spec);
}
}
ret.extend_from_slice(specs);
ret
}
pub fn get_local_specs(&self) -> &[SideMetadataSpec] {
&self.local
}
/// Return the pages reserved for side metadata based on the data pages we used.
// We used to use PageAccouting to count pages used in side metadata. However,
// that means we always count pages while we may reserve less than a page each time.
// This could lead to overcount. I think the easier way is to not account
// when we allocate for sidemetadata, but to calculate the side metadata usage based on
// how many data pages we use when reporting.
pub fn calculate_reserved_pages(&self, data_pages: usize) -> usize {
let mut total = 0;
for spec in self.global.iter() {
let rshift = addr_rshift(spec);
total += (data_pages + ((1 << rshift) - 1)) >> rshift;
}
for spec in self.local.iter() {
let rshift = addr_rshift(spec);
total += (data_pages + ((1 << rshift) - 1)) >> rshift;
}
total
}
// ** NOTE: **
// Regardless of the number of bits in a metadata unit, we always represent its content as a word.
/// Tries to map the required metadata space and returns `true` is successful.
/// This can be called at page granularity.
pub fn try_map_metadata_space(&self, start: Address, size: usize) -> Result<()> {
debug!(
"try_map_metadata_space({}, 0x{:x}, {}, {})",
start,
size,
self.global.len(),
self.local.len()
);
// Page aligned
debug_assert!(start.is_aligned_to(BYTES_IN_PAGE));
debug_assert!(size % BYTES_IN_PAGE == 0);
self.map_metadata_internal(start, size, false)
}
/// Tries to map the required metadata address range, without reserving swap-space/physical memory for it.
/// This will make sure the address range is exclusive to the caller. This should be called at chunk granularity.
///
/// NOTE: Accessing addresses in this range will produce a segmentation fault if swap-space is not mapped using the `try_map_metadata_space` function.
pub fn try_map_metadata_address_range(&self, start: Address, size: usize) -> Result<()> {
debug!(
"try_map_metadata_address_range({}, 0x{:x}, {}, {})",
start,
size,
self.global.len(),
self.local.len()
);
// Chunk aligned
debug_assert!(start.is_aligned_to(BYTES_IN_CHUNK));
debug_assert!(size % BYTES_IN_CHUNK == 0);
self.map_metadata_internal(start, size, true)
}
/// The internal function to mmap metadata
///
/// # Arguments
/// * `start` - The starting address of the source data.
/// * `size` - The size of the source data (in bytes).
/// * `no_reserve` - whether to invoke mmap with a noreserve flag (we use this flag to quarantine address range)
fn map_metadata_internal(&self, start: Address, size: usize, no_reserve: bool) -> Result<()> {
for spec in self.global.iter() {
match try_mmap_contiguous_metadata_space(start, size, spec, no_reserve) {
Ok(_) => {}
Err(e) => return Result::Err(e),
}
}
#[cfg(target_pointer_width = "32")]
let mut lsize: usize = 0;
for spec in self.local.iter() {
// For local side metadata, we always have to reserve address space for all local
// metadata required by all policies in MMTk to be able to calculate a constant offset
// for each local metadata at compile-time (it's like assigning an ID to each policy).
//
// As the plan is chosen at run-time, we will never know which subset of policies will
// be used during run-time. We can't afford this much address space in 32-bits.
// So, we switch to the chunk-based approach for this specific case.
//
// The global metadata is different in that for each plan, we can calculate its constant
// base addresses at compile-time. Using the chunk-based approach will need the same
// address space size as the current not-chunked approach.
#[cfg(target_pointer_width = "64")]
{
match try_mmap_contiguous_metadata_space(start, size, spec, no_reserve) {
Ok(_) => {}
Err(e) => return Result::Err(e),
}
}
#[cfg(target_pointer_width = "32")]
{
lsize += metadata_bytes_per_chunk(spec.log_bytes_in_region, spec.log_num_of_bits);
}
}
#[cfg(target_pointer_width = "32")]
if lsize > 0 {
let max = BYTES_IN_CHUNK >> super::constants::LOG_LOCAL_SIDE_METADATA_WORST_CASE_RATIO;
debug_assert!(
lsize <= max,
"local side metadata per chunk (0x{:x}) must be less than (0x{:x})",
lsize,
max
);
match try_map_per_chunk_metadata_space(start, size, lsize, no_reserve) {
Ok(_) => {}
Err(e) => return Result::Err(e),
}
}
Ok(())
}
/// Unmap the corresponding metadata space or panic.
///
/// Note-1: This function is only used for test and debug right now.
///
/// Note-2: This function uses munmap() which works at page granularity.
/// If the corresponding metadata space's size is not a multiple of page size,
/// the actual unmapped space will be bigger than what you specify.
#[cfg(test)]
pub fn ensure_unmap_metadata_space(&self, start: Address, size: usize) {
trace!("ensure_unmap_metadata_space({}, 0x{:x})", start, size);
debug_assert!(start.is_aligned_to(BYTES_IN_PAGE));
debug_assert!(size % BYTES_IN_PAGE == 0);
for spec in self.global.iter() {
ensure_munmap_contiguous_metadata_space(start, size, spec);
}
for spec in self.local.iter() {
#[cfg(target_pointer_width = "64")]
{
ensure_munmap_contiguous_metadata_space(start, size, spec);
}
#[cfg(target_pointer_width = "32")]
{
ensure_munmap_chunked_metadata_space(start, size, spec);
}
}
}
}
/// A byte array in side-metadata
pub struct MetadataByteArrayRef<const ENTRIES: usize> {
#[cfg(feature = "extreme_assertions")]
heap_range_start: Address,
#[cfg(feature = "extreme_assertions")]
spec: SideMetadataSpec,
data: &'static [u8; ENTRIES],
}
impl<const ENTRIES: usize> MetadataByteArrayRef<ENTRIES> {
/// Get a piece of metadata address range as a byte array.
///
/// # Arguments
///
/// * `metadata_spec` - The specification of the target side metadata.
/// * `start` - The starting address of the heap range.
/// * `bytes` - The size of the heap range.
///
pub fn new(metadata_spec: &SideMetadataSpec, start: Address, bytes: usize) -> Self {
debug_assert_eq!(
metadata_spec.log_num_of_bits, LOG_BITS_IN_BYTE as usize,
"Each heap entry should map to a byte in side-metadata"
);
debug_assert_eq!(
bytes >> metadata_spec.log_bytes_in_region,
ENTRIES,
"Heap range size and MetadataByteArray size does not match"
);
Self {
#[cfg(feature = "extreme_assertions")]
heap_range_start: start,
#[cfg(feature = "extreme_assertions")]
spec: *metadata_spec,
// # Safety
// The metadata memory is assumed to be mapped when accessing.
data: unsafe { &*address_to_meta_address(metadata_spec, start).to_ptr() },
}
}
/// Get the length of the array.
#[allow(clippy::len_without_is_empty)]
pub const fn len(&self) -> usize {
ENTRIES
}
/// Get a byte from the metadata byte array at the given index.
#[allow(clippy::let_and_return)]
pub fn get(&self, index: usize) -> u8 {
#[cfg(feature = "extreme_assertions")]
let _lock = sanity::SANITY_LOCK.lock().unwrap();
let value = self.data[index];
#[cfg(feature = "extreme_assertions")]
{
let data_addr = self.heap_range_start + (index << self.spec.log_bytes_in_region);
sanity::verify_load::<u8>(&self.spec, data_addr, value);
}
value
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::util::metadata::side_metadata::SideMetadataContext;
// offset is not used in these tests.
pub const ZERO_OFFSET: SideMetadataOffset = SideMetadataOffset { rel_offset: 0 };
#[test]
fn calculate_reserved_pages_one_spec() {
// 1 bit per 8 bytes - 1:64
let spec = SideMetadataSpec {
name: "test_spec",
is_global: true,
offset: ZERO_OFFSET,
log_num_of_bits: 0,
log_bytes_in_region: 3,
};
let side_metadata = SideMetadataContext {
global: vec![spec],
local: vec![],
};
assert_eq!(side_metadata.calculate_reserved_pages(0), 0);
assert_eq!(side_metadata.calculate_reserved_pages(63), 1);
assert_eq!(side_metadata.calculate_reserved_pages(64), 1);
assert_eq!(side_metadata.calculate_reserved_pages(65), 2);
assert_eq!(side_metadata.calculate_reserved_pages(1024), 16);
}
#[test]
fn calculate_reserved_pages_multi_specs() {
// 1 bit per 8 bytes - 1:64
let gspec = SideMetadataSpec {
name: "gspec",
is_global: true,
offset: ZERO_OFFSET,
log_num_of_bits: 0,
log_bytes_in_region: 3,
};
// 2 bits per page - 2 / (4k * 8) = 1:16k
let lspec = SideMetadataSpec {
name: "lspec",
is_global: false,
offset: ZERO_OFFSET,
log_num_of_bits: 1,
log_bytes_in_region: 12,
};
let side_metadata = SideMetadataContext {
global: vec![gspec],
local: vec![lspec],
};
assert_eq!(side_metadata.calculate_reserved_pages(1024), 16 + 1);
}
use crate::util::heap::layout::vm_layout;
use crate::util::test_util::{serial_test, with_cleanup};
use memory::MmapStrategy;
use paste::paste;
const TEST_LOG_BYTES_IN_REGION: usize = 12;
fn test_side_metadata(
log_bits: usize,
f: impl Fn(&SideMetadataSpec, Address, Address) + std::panic::RefUnwindSafe,
) {
serial_test(|| {
let spec = SideMetadataSpec {
name: "Test Spec $tname",
is_global: true,
offset: SideMetadataOffset::addr(GLOBAL_SIDE_METADATA_BASE_ADDRESS),
log_num_of_bits: log_bits,
log_bytes_in_region: TEST_LOG_BYTES_IN_REGION, // page size
};
let context = SideMetadataContext {
global: vec![spec],
local: vec![],
};
let mut sanity = SideMetadataSanity::new();
sanity.verify_metadata_context("TestPolicy", &context);
let data_addr = vm_layout::vm_layout().heap_start;
// Make sure the address is mapped.
crate::MMAPPER
.ensure_mapped(data_addr, 1, MmapStrategy::TEST)
.unwrap();
let meta_addr = address_to_meta_address(&spec, data_addr);
with_cleanup(
|| {
let mmap_result = context.try_map_metadata_space(data_addr, BYTES_IN_PAGE);
assert!(mmap_result.is_ok());
f(&spec, data_addr, meta_addr);
},
|| {
// Clear the metadata -- use u64 (max length we support)
assert!(log_bits <= 6);
let meta_ptr: *mut u64 = meta_addr.to_mut_ptr();
unsafe { *meta_ptr = 0 };
sanity::reset();
},
)
})
}
fn max_value(log_bits: usize) -> u64 {
(0..(1 << log_bits)).fold(0, |accum, x| accum + (1 << x))
}
#[test]
fn test_max_value() {
assert_eq!(max_value(0), 1);
assert_eq!(max_value(1), 0b11);
assert_eq!(max_value(2), 0b1111);
assert_eq!(max_value(3), 255);
assert_eq!(max_value(4), 65535);
}
macro_rules! test_side_metadata_access {
($tname: ident, $type: ty, $log_bits: expr) => {
paste!{
#[test]
fn [<$tname _load>]() {
test_side_metadata($log_bits, |spec, data_addr, meta_addr| {
let meta_ptr: *mut $type = meta_addr.to_mut_ptr();
// Initial value should be 0
assert_eq!(unsafe { spec.load::<$type>(data_addr) }, 0);
assert_eq!(spec.load_atomic::<$type>(data_addr, Ordering::SeqCst), 0);
// Set to max
let max_value: $type = max_value($log_bits) as _;
unsafe { spec.store::<$type>(data_addr, max_value); }
assert_eq!(unsafe { spec.load::<$type>(data_addr) }, max_value);
assert_eq!(spec.load_atomic::<$type>(data_addr, Ordering::SeqCst), max_value);
assert_eq!(unsafe { *meta_ptr }, max_value);
});
}
#[test]
fn [<$tname _store>]() {
test_side_metadata($log_bits, |spec, data_addr, meta_addr| {
let meta_ptr: *mut $type = meta_addr.to_mut_ptr();
let max_value: $type = max_value($log_bits) as _;
// Set the metadata byte(s) to all 1s
unsafe { *meta_ptr = <$type>::MAX; }
// Store 0 to the side metadata
unsafe { spec.store::<$type>(data_addr, 0); }
assert_eq!(unsafe { spec.load::<$type>(data_addr) }, 0);
// Only the affected bits are set to 0
assert_eq!(unsafe { *meta_ptr }, <$type>::MAX & (!max_value));
});
}
#[test]
fn [<$tname _atomic_store>]() {
test_side_metadata($log_bits, |spec, data_addr, meta_addr| {
let meta_ptr: *mut $type = meta_addr.to_mut_ptr();
let max_value: $type = max_value($log_bits) as _;
// Set the metadata byte(s) to all 1s
unsafe { *meta_ptr = <$type>::MAX; }
// Store 0 to the side metadata
spec.store_atomic::<$type>(data_addr, 0, Ordering::SeqCst);
assert_eq!(unsafe { spec.load::<$type>(data_addr) }, 0);
// Only the affected bits are set to 0
assert_eq!(unsafe { *meta_ptr }, <$type>::MAX & (!max_value));
});
}
#[test]
fn [<$tname _compare_exchange_success>]() {
test_side_metadata($log_bits, |spec, data_addr, meta_addr| {
let meta_ptr: *mut $type = meta_addr.to_mut_ptr();
let max_value: $type = max_value($log_bits) as _;
// Set the metadata byte(s) to all 1s
unsafe { *meta_ptr = <$type>::MAX; }
// Store 1 to the side metadata
spec.store_atomic::<$type>(data_addr, 1, Ordering::SeqCst);
let old_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
assert_eq!(old_val, 1);
let new_val = 0;
let res = spec.compare_exchange_atomic::<$type>(data_addr, old_val, new_val, Ordering::SeqCst, Ordering::SeqCst);
assert!(res.is_ok());
assert_eq!(res.unwrap(), old_val, "old vals do not match");
let after_update = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
assert_eq!(after_update, new_val);
// Only the affected bits are set to 0
assert_eq!(unsafe { *meta_ptr }, <$type>::MAX & (!max_value));
});
}
#[test]
fn [<$tname _compare_exchange_fail>]() {
test_side_metadata($log_bits, |spec, data_addr, meta_addr| {
let meta_ptr: *mut $type = meta_addr.to_mut_ptr();
// Set the metadata byte(s) to all 1s
unsafe { *meta_ptr = <$type>::MAX; }
// Store 1 to the side metadata
spec.store_atomic::<$type>(data_addr, 1, Ordering::SeqCst);
let old_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
assert_eq!(old_val, 1);
// make old_val outdated
spec.store_atomic::<$type>(data_addr, 0, Ordering::SeqCst);
let bits_before_cas = unsafe { *meta_ptr };
let new_val = 0;
let res = spec.compare_exchange_atomic::<$type>(data_addr, old_val, new_val, Ordering::SeqCst, Ordering::SeqCst);
assert!(res.is_err());
assert_eq!(res.err().unwrap(), 0);
let bits_after_cas = unsafe { *meta_ptr };
assert_eq!(bits_before_cas, bits_after_cas);
});
}
#[test]
fn [<$tname _fetch_add_1>]() {
test_side_metadata($log_bits, |spec, data_addr, meta_addr| {
let meta_ptr: *mut $type = meta_addr.to_mut_ptr();
// Set the metadata byte(s) to all 1s
unsafe { *meta_ptr = <$type>::MAX; }
// Store 0 to the side metadata
spec.store_atomic::<$type>(data_addr, 0, Ordering::SeqCst);
let old_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
let old_val_from_fetch = spec.fetch_add_atomic::<$type>(data_addr, 1, Ordering::SeqCst);
assert_eq!(old_val_from_fetch, old_val);
let new_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
assert_eq!(new_val, 1);
});
}
#[test]
fn [<$tname _fetch_add_max>]() {
test_side_metadata($log_bits, |spec, data_addr, meta_addr| {
let meta_ptr: *mut $type = meta_addr.to_mut_ptr();
let max_value: $type = max_value($log_bits) as _;
// Set the metadata byte(s) to all 1s
unsafe { *meta_ptr = <$type>::MAX; }
// Store 0 to the side metadata
spec.store_atomic::<$type>(data_addr, 0, Ordering::SeqCst);
let old_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
let old_val_from_fetch = spec.fetch_add_atomic::<$type>(data_addr, max_value, Ordering::SeqCst);
assert_eq!(old_val_from_fetch, old_val);
let new_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
assert_eq!(new_val, max_value);
});
}
#[test]
fn [<$tname _fetch_add_overflow>]() {
test_side_metadata($log_bits, |spec, data_addr, meta_addr| {
let meta_ptr: *mut $type = meta_addr.to_mut_ptr();
let max_value: $type = max_value($log_bits) as _;
// Set the metadata byte(s) to all 1s
unsafe { *meta_ptr = <$type>::MAX; }
// Store max to the side metadata
spec.store_atomic::<$type>(data_addr, max_value, Ordering::SeqCst);
let old_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
// add 1 to max value will cause overflow and wrap around to 0
let old_val_from_fetch = spec.fetch_add_atomic::<$type>(data_addr, 1, Ordering::SeqCst);
assert_eq!(old_val_from_fetch, old_val);
let new_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
assert_eq!(new_val, 0);
});
}
#[test]
fn [<$tname _fetch_sub_1>]() {
test_side_metadata($log_bits, |spec, data_addr, meta_addr| {
let meta_ptr: *mut $type = meta_addr.to_mut_ptr();
// Set the metadata byte(s) to all 1s
unsafe { *meta_ptr = <$type>::MAX; }
// Store 1 to the side metadata
spec.store_atomic::<$type>(data_addr, 1, Ordering::SeqCst);
let old_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
let old_val_from_fetch = spec.fetch_sub_atomic::<$type>(data_addr, 1, Ordering::SeqCst);
assert_eq!(old_val_from_fetch, old_val);
let new_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
assert_eq!(new_val, 0);
});
}
#[test]
fn [<$tname _fetch_sub_max>]() {
test_side_metadata($log_bits, |spec, data_addr, meta_addr| {
let meta_ptr: *mut $type = meta_addr.to_mut_ptr();
let max_value: $type = max_value($log_bits) as _;
// Set the metadata byte(s) to all 1s
unsafe { *meta_ptr = <$type>::MAX; }
// Store max to the side metadata
spec.store_atomic::<$type>(data_addr, max_value, Ordering::SeqCst);
let old_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
let old_val_from_fetch = spec.fetch_sub_atomic::<$type>(data_addr, max_value, Ordering::SeqCst);
assert_eq!(old_val_from_fetch, old_val);
let new_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
assert_eq!(new_val, 0);
});
}
#[test]
fn [<$tname _fetch_sub_overflow>]() {
test_side_metadata($log_bits, |spec, data_addr, meta_addr| {
let meta_ptr: *mut $type = meta_addr.to_mut_ptr();
let max_value: $type = max_value($log_bits) as _;
// Set the metadata byte(s) to all 1s
unsafe { *meta_ptr = <$type>::MAX; }
// Store 0 to the side metadata
spec.store_atomic::<$type>(data_addr, 0, Ordering::SeqCst);
let old_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
// sub 1 from 0 will cause overflow, and wrap around to max
let old_val_from_fetch = spec.fetch_sub_atomic::<$type>(data_addr, 1, Ordering::SeqCst);
assert_eq!(old_val_from_fetch, old_val);
let new_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
assert_eq!(new_val, max_value);
});
}
#[test]
fn [<$tname _fetch_and>]() {
test_side_metadata($log_bits, |spec, data_addr, meta_addr| {
let meta_ptr: *mut $type = meta_addr.to_mut_ptr();
let max_value: $type = max_value($log_bits) as _;
// Set the metadata byte(s) to all 1s
unsafe { *meta_ptr = <$type>::MAX; }
// Store all 1s to the side metadata
spec.store_atomic::<$type>(data_addr, max_value, Ordering::SeqCst);
// max and max should be max
let old_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
let old_val_from_fetch = spec.fetch_and_atomic::<$type>(data_addr, max_value, Ordering::SeqCst);
assert_eq!(old_val_from_fetch, old_val, "old values do not match");
assert_eq!(spec.load_atomic::<$type>(data_addr, Ordering::SeqCst), max_value, "load values do not match");
assert_eq!(unsafe { *meta_ptr }, <$type>::MAX, "raw values do not match");
// max and last_bit_zero should last_bit_zero
let last_bit_zero = max_value - 1;
let old_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
let old_val_from_fetch = spec.fetch_and_atomic::<$type>(data_addr, last_bit_zero, Ordering::SeqCst);
assert_eq!(old_val_from_fetch, old_val);
assert_eq!(spec.load_atomic::<$type>(data_addr, Ordering::SeqCst), last_bit_zero);
assert_eq!(unsafe { *meta_ptr }, <$type>::MAX - 1);
});
}
#[test]
fn [<$tname _fetch_or>]() {
test_side_metadata($log_bits, |spec, data_addr, meta_addr| {
let meta_ptr: *mut $type = meta_addr.to_mut_ptr();
let max_value: $type = max_value($log_bits) as _;
// Set the metadata byte(s) to all 0s
unsafe { *meta_ptr = 0; }
// Store 0 to the side metadata
spec.store_atomic::<$type>(data_addr, 0, Ordering::SeqCst);
// 0 or 0 should be 0
let old_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
let old_val_from_fetch = spec.fetch_or_atomic::<$type>(data_addr, 0, Ordering::SeqCst);
assert_eq!(old_val_from_fetch, old_val);
assert_eq!(spec.load_atomic::<$type>(data_addr, Ordering::SeqCst), 0);
assert_eq!(unsafe { *meta_ptr }, 0);
// 0 and max should max
let old_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
let old_val_from_fetch = spec.fetch_or_atomic::<$type>(data_addr, max_value, Ordering::SeqCst);
assert_eq!(old_val_from_fetch, old_val);
assert_eq!(spec.load_atomic::<$type>(data_addr, Ordering::SeqCst), max_value);
assert_eq!(unsafe { *meta_ptr }, max_value);
});
}
#[test]
fn [<$tname _fetch_update_success>]() {
test_side_metadata($log_bits, |spec, data_addr, meta_addr| {
let meta_ptr: *mut $type = meta_addr.to_mut_ptr();
let max_value: $type = max_value($log_bits) as _;
// Set the metadata byte(s) to all 1s
unsafe { *meta_ptr = <$type>::MAX; }
// Store all 1s to the side metadata
spec.store_atomic::<$type>(data_addr, max_value, Ordering::SeqCst);
// update from max to zero
let old_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
let fetch_res = spec.fetch_update_atomic::<$type, _>(data_addr, Ordering::SeqCst, Ordering::SeqCst, |_x: $type| Some(0));
assert!(fetch_res.is_ok());
assert_eq!(fetch_res.unwrap(), old_val);
assert_eq!(spec.load_atomic::<$type>(data_addr, Ordering::SeqCst), 0);
// Only the affected bits are set to 0
assert_eq!(unsafe { *meta_ptr }, <$type>::MAX & (!max_value));
});
}
#[test]
fn [<$tname _fetch_update_fail>]() {
test_side_metadata($log_bits, |spec, data_addr, meta_addr| {
let meta_ptr: *mut $type = meta_addr.to_mut_ptr();
let max_value: $type = max_value($log_bits) as _;
// Set the metadata byte(s) to all 1s
unsafe { *meta_ptr = <$type>::MAX; }
// Store all 1s to the side metadata
spec.store_atomic::<$type>(data_addr, max_value, Ordering::SeqCst);
// update from max to zero
let old_val = spec.load_atomic::<$type>(data_addr, Ordering::SeqCst);
let fetch_res = spec.fetch_update_atomic::<$type, _>(data_addr, Ordering::SeqCst, Ordering::SeqCst, |_x: $type| None);
assert!(fetch_res.is_err());
assert_eq!(fetch_res.err().unwrap(), old_val);
assert_eq!(spec.load_atomic::<$type>(data_addr, Ordering::SeqCst), max_value);
// Only the affected bits are set to 0
assert_eq!(unsafe { *meta_ptr }, <$type>::MAX);
});
}
#[test]
fn [<$tname _find_prev_non_zero_value_easy>]() {
test_side_metadata($log_bits, |spec, data_addr, _meta_addr| {
let max_value: $type = max_value($log_bits) as _;
// Store non zero value at data_addr
spec.store_atomic::<$type>(data_addr, max_value, Ordering::SeqCst);
// Find the value starting from data_addr, at max 8 bytes.
// We should find data_addr
let res_addr = unsafe { spec.find_prev_non_zero_value::<$type>(data_addr, 8) };
assert!(res_addr.is_some());
assert_eq!(res_addr.unwrap(), data_addr);
});
}
#[test]
fn [<$tname _find_prev_non_zero_value_arbitrary_bytes>]() {
test_side_metadata($log_bits, |spec, data_addr, _meta_addr| {
let max_value: $type = max_value($log_bits) as _;
// Store non zero value at data_addr
spec.store_atomic::<$type>(data_addr, max_value, Ordering::SeqCst);
// Start from data_addr, we offset arbitrary length, and search back to find data_addr
let test_region = (1 << TEST_LOG_BYTES_IN_REGION);
for len in 1..(test_region*4) {
let start_addr = data_addr + len;
// Use len+1, as len is non inclusive.
let res_addr = unsafe { spec.find_prev_non_zero_value::<$type>(start_addr, len + 1) };
assert!(res_addr.is_some());
assert_eq!(res_addr.unwrap(), data_addr);
}
});
}
#[test]
fn [<$tname _find_prev_non_zero_value_arbitrary_start>]() {
test_side_metadata($log_bits, |spec, data_addr, _meta_addr| {
let max_value: $type = max_value($log_bits) as _;
// data_addr has a non-aligned offset
for offset in 0..7usize {
// Apply offset and test with the new data addr
let test_data_addr = data_addr + offset;
spec.store_atomic::<$type>(test_data_addr, max_value, Ordering::SeqCst);
// The return result should be aligned
let res_addr = unsafe { spec.find_prev_non_zero_value::<$type>(test_data_addr, 4096) };
assert!(res_addr.is_some());
assert_eq!(res_addr.unwrap(), data_addr);
// Clear whatever is set
spec.store_atomic::<$type>(test_data_addr, 0, Ordering::SeqCst);
}
});
}
#[test]
fn [<$tname _find_prev_non_zero_value_no_find>]() {
test_side_metadata($log_bits, |spec, data_addr, _meta_addr| {
// Store zero value at data_addr -- so we won't find anything
spec.store_atomic::<$type>(data_addr, 0, Ordering::SeqCst);
// Start from data_addr, we offset arbitrary length, and search back
let test_region = (1 << TEST_LOG_BYTES_IN_REGION);
for len in 1..(test_region*4) {
let start_addr = data_addr + len;
// Use len+1, as len is non inclusive.
let res_addr = unsafe { spec.find_prev_non_zero_value::<$type>(start_addr, len + 1) };
assert!(res_addr.is_none());
}
});
}
}
}
}
test_side_metadata_access!(test_u1, u8, 0);
test_side_metadata_access!(test_u2, u8, 1);
test_side_metadata_access!(test_u4, u8, 2);
test_side_metadata_access!(test_u8, u8, 3);
test_side_metadata_access!(test_u16, u16, 4);
test_side_metadata_access!(test_u32, u32, 5);
test_side_metadata_access!(test_u64, u64, 6);
test_side_metadata_access!(
test_usize,
usize,
if cfg!(target_pointer_width = "64") {
6
} else if cfg!(target_pointer_width = "32") {
5
} else {
unreachable!()
}
);
#[test]
fn test_bulk_update_meta_bits() {
let raw_mem =
unsafe { std::alloc::alloc_zeroed(std::alloc::Layout::from_size_align(8, 8).unwrap()) };
let addr = Address::from_mut_ptr(raw_mem);
SideMetadataSpec::set_meta_bits(addr, 0, addr, 4);
assert_eq!(unsafe { addr.load::<u64>() }, 0b1111);
SideMetadataSpec::zero_meta_bits(addr, 1, addr, 3);
assert_eq!(unsafe { addr.load::<u64>() }, 0b1001);
SideMetadataSpec::set_meta_bits(addr, 2, addr, 6);
assert_eq!(unsafe { addr.load::<u64>() }, 0b0011_1101);
SideMetadataSpec::zero_meta_bits(addr, 0, addr + 1usize, 0);
assert_eq!(unsafe { addr.load::<u64>() }, 0b0);
SideMetadataSpec::set_meta_bits(addr, 2, addr + 1usize, 2);
assert_eq!(unsafe { addr.load::<u64>() }, 0b11_1111_1100);
SideMetadataSpec::set_meta_bits(addr, 0, addr + 1usize, 2);
assert_eq!(unsafe { addr.load::<u64>() }, 0b11_1111_1111);
}
}