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Optimize the queries for intersected intervals in Vmar from O(n) to O(log(n))

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This commit is contained in:
Wang Siyuan
2024-02-02 19:04:12 +08:00
committed by Tate, Hongliang Tian
parent eb4161a56e
commit dbba7c2bad
4 changed files with 240 additions and 126 deletions
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1
services/libs/aster-std/src/lib.rs
View File

@ -22,6 +22,7 @@
#![feature(format_args_nl)]
#![feature(int_roundings)]
#![feature(step_trait)]
#![feature(btree_cursors)]
#![register_tool(component_access_control)]
use crate::{

26
services/libs/aster-std/src/vm/vmar/interval.rs Normal file
View File

@ -0,0 +1,26 @@
// SPDX-License-Identifier: MPL-2.0
//! Intervals and interval sets used in VMARs.
use core::ops::Range;
/// An interval is associated with a range of values (`T`).
pub trait Interval<T> {
/// Returns the range of the interval.
fn range(&self) -> Range<T>;
}
/// A collection that contains intervals as items. In particular,
/// the collection allows one to retrieve interval items that intersect with
/// a point of value or range of values.
pub trait IntervalSet<'a, T> {
type Item: Interval<T> + 'a;
/// Find the interval items that overlap with a specific range.
fn find(&'a self, range: &Range<T>) -> impl IntoIterator<Item = &'a Self::Item> + 'a;
/// Finds one interval item that contains the point.
///
/// If there are multiple such items, then an arbitrary one is returned.
fn find_one(&'a self, point: &T) -> Option<&'a Self::Item>;
}

327
services/libs/aster-std/src/vm/vmar/mod.rs
View File

@ -3,6 +3,7 @@
//! Virtual Memory Address Regions (VMARs).
mod dyn_cap;
mod interval;
mod options;
mod static_cap;
pub mod vm_mapping;
@ -18,6 +19,7 @@ use aster_frame::vm::VmSpace;
use aster_rights::Rights;
use core::ops::Range;
use self::interval::{Interval, IntervalSet};
use self::vm_mapping::VmMapping;
use super::page_fault_handler::PageFaultHandler;
@ -131,6 +133,12 @@ impl VmarInner {
const ROOT_VMAR_LOWEST_ADDR: Vaddr = 0x0010_0000;
const ROOT_VMAR_HIGHEST_ADDR: Vaddr = 0x1000_0000_0000;
impl Interval<usize> for Arc<Vmar_> {
fn range(&self) -> Range<usize> {
self.base..(self.base + self.size)
}
}
impl Vmar_ {
fn new(
inner: VmarInner,
@ -181,20 +189,20 @@ impl Vmar_ {
// do real protect. The protected range is ensured to be mapped.
fn do_protect_inner(&self, perms: VmPerms, range: Range<usize>) -> Result<()> {
for (vm_mapping_base, vm_mapping) in &self.inner.lock().vm_mappings {
let vm_mapping_range = *vm_mapping_base..(*vm_mapping_base + vm_mapping.map_size());
if is_intersected(&range, &vm_mapping_range) {
let intersected_range = get_intersected_range(&range, &vm_mapping_range);
vm_mapping.protect(perms, intersected_range)?;
}
let inner = self.inner.lock();
for vm_mapping in inner.vm_mappings.find(&range) {
let vm_mapping_range = vm_mapping.range();
debug_assert!(is_intersected(&vm_mapping_range, &range));
let intersected_range = get_intersected_range(&range, &vm_mapping_range);
vm_mapping.protect(perms, intersected_range)?;
}
for child_vmar_ in self.inner.lock().child_vmar_s.values() {
for child_vmar_ in inner.child_vmar_s.find(&range) {
let child_vmar_range = child_vmar_.range();
if is_intersected(&range, &child_vmar_range) {
let intersected_range = get_intersected_range(&range, &child_vmar_range);
child_vmar_.do_protect_inner(perms, intersected_range)?;
}
debug_assert!(is_intersected(&child_vmar_range, &range));
let intersected_range = get_intersected_range(&range, &child_vmar_range);
child_vmar_.do_protect_inner(perms, intersected_range)?;
}
Ok(())
@ -209,19 +217,23 @@ impl Vmar_ {
assert!(protected_range.end <= self.base + self.size);
// The protected range should not interstect with any free region
for free_region in self.inner.lock().free_regions.values() {
if is_intersected(&free_region.range, protected_range) {
return_errno_with_message!(Errno::EACCES, "protected range is not fully mapped");
}
let inner = self.inner.lock();
if inner
.free_regions
.find(protected_range)
.into_iter()
.next()
.is_some()
{
return_errno_with_message!(Errno::EACCES, "protected range is not fully mapped");
}
// if the protected range intersects with child vmar_, child vmar_ is responsible to do the check.
for child_vmar_ in self.inner.lock().child_vmar_s.values() {
let child_range = child_vmar_.range();
if is_intersected(&child_range, protected_range) {
let intersected_range = get_intersected_range(&child_range, protected_range);
child_vmar_.check_protected_range(&intersected_range)?;
}
for child_vmar_ in inner.child_vmar_s.find(protected_range) {
let child_vmar_range = child_vmar_.range();
debug_assert!(is_intersected(&child_vmar_range, protected_range));
let intersected_range = get_intersected_range(protected_range, &child_vmar_range);
child_vmar_.check_protected_range(&intersected_range)?;
}
Ok(())
@ -239,21 +251,21 @@ impl Vmar_ {
}
let inner = self.inner.lock();
for (child_vmar_base, child_vmar) in &inner.child_vmar_s {
if *child_vmar_base <= page_fault_addr
&& page_fault_addr < *child_vmar_base + child_vmar.size
{
return child_vmar.handle_page_fault(page_fault_addr, not_present, write);
}
if let Some(child_vmar) = inner.child_vmar_s.find_one(&page_fault_addr) {
debug_assert!(is_intersected(
&child_vmar.range(),
&(page_fault_addr..page_fault_addr + 1)
));
return child_vmar.handle_page_fault(page_fault_addr, not_present, write);
}
// FIXME: If multiple vmos are mapped to the addr, should we allow all vmos to handle page fault?
for (vm_mapping_base, vm_mapping) in &inner.vm_mappings {
if *vm_mapping_base <= page_fault_addr
&& page_fault_addr < *vm_mapping_base + vm_mapping.map_size()
{
return vm_mapping.handle_page_fault(page_fault_addr, not_present, write);
}
if let Some(vm_mapping) = inner.vm_mappings.find_one(&page_fault_addr) {
debug_assert!(is_intersected(
&vm_mapping.range(),
&(page_fault_addr..page_fault_addr + 1)
));
return vm_mapping.handle_page_fault(page_fault_addr, not_present, write);
}
return_errno_with_message!(Errno::EACCES, "page fault addr is not in current vmar");
@ -305,11 +317,11 @@ impl Vmar_ {
self.check_destroy_range(&range)?;
let mut inner = self.inner.lock();
let mut free_regions = BTreeMap::new();
for (child_vmar_base, child_vmar) in &inner.child_vmar_s {
let child_vmar_range = child_vmar.range();
if is_intersected(&range, &child_vmar_range) {
child_vmar.destroy_all()?;
}
for child_vmar_ in inner.child_vmar_s.find(&range) {
let child_vmar_range = child_vmar_.range();
debug_assert!(is_intersected(&child_vmar_range, &range));
child_vmar_.destroy_all()?;
let free_region = FreeRegion::new(child_vmar_range);
free_regions.insert(free_region.start(), free_region);
}
@ -320,18 +332,18 @@ impl Vmar_ {
let mut mappings_to_remove = BTreeSet::new();
let mut mappings_to_append = BTreeMap::new();
for vm_mapping in inner.vm_mappings.values() {
for vm_mapping in inner.vm_mappings.find(&range) {
let vm_mapping_range = vm_mapping.range();
if is_intersected(&vm_mapping_range, &range) {
let intersected_range = get_intersected_range(&vm_mapping_range, &range);
vm_mapping.trim_mapping(
&intersected_range,
&mut mappings_to_remove,
&mut mappings_to_append,
)?;
let free_region = FreeRegion::new(intersected_range);
free_regions.insert(free_region.start(), free_region);
}
debug_assert!(is_intersected(&vm_mapping_range, &range));
let intersected_range = get_intersected_range(&vm_mapping_range, &range);
vm_mapping.trim_mapping(
&intersected_range,
&mut mappings_to_remove,
&mut mappings_to_append,
)?;
let free_region = FreeRegion::new(intersected_range);
free_regions.insert(free_region.start(), free_region);
}
for mapping in mappings_to_remove {
@ -354,21 +366,18 @@ impl Vmar_ {
debug_assert!(range.start % PAGE_SIZE == 0);
debug_assert!(range.end % PAGE_SIZE == 0);
for (child_vmar_base, child_vmar) in &self.inner.lock().child_vmar_s {
let child_vmar_start = *child_vmar_base;
let child_vmar_end = child_vmar_start + child_vmar.size;
if child_vmar_end <= range.start || child_vmar_start >= range.end {
// child vmar does not intersect with range
continue;
}
if range.start <= child_vmar_start && child_vmar_end <= range.end {
let inner = self.inner.lock();
for child_vmar_ in inner.child_vmar_s.find(range) {
let child_vmar_range = child_vmar_.range();
debug_assert!(is_intersected(&child_vmar_range, range));
if range.start <= child_vmar_range.start && child_vmar_range.end <= range.end {
// child vmar is totolly in the range
continue;
}
assert!(is_intersected(range, &(child_vmar_start..child_vmar_end)));
return_errno_with_message!(
Errno::EACCES,
"Child vmar is partly intersected with destryed range"
"Child vmar is partly intersected with destroyed range"
);
}
@ -400,19 +409,22 @@ impl Vmar_ {
pub fn read(&self, offset: usize, buf: &mut [u8]) -> Result<()> {
let read_start = self.base + offset;
let read_end = buf.len() + read_start;
let read_range = read_start..read_end;
// if the read range is in child vmar
for (child_vmar_base, child_vmar) in &self.inner.lock().child_vmar_s {
let child_vmar_end = *child_vmar_base + child_vmar.size;
if *child_vmar_base <= read_start && read_end <= child_vmar_end {
let child_offset = read_start - *child_vmar_base;
return child_vmar.read(child_offset, buf);
let inner = self.inner.lock();
for child_vmar_ in inner.child_vmar_s.find(&read_range) {
let child_vmar_range = child_vmar_.range();
if child_vmar_range.start <= read_start && read_end <= child_vmar_range.end {
let child_offset = read_start - child_vmar_range.start;
return child_vmar_.read(child_offset, buf);
}
}
// if the read range is in mapped vmo
for (vm_mapping_base, vm_mapping) in &self.inner.lock().vm_mappings {
let vm_mapping_end = *vm_mapping_base + vm_mapping.map_size();
if *vm_mapping_base <= read_start && read_end <= vm_mapping_end {
let vm_mapping_offset = read_start - *vm_mapping_base;
for vm_mapping in inner.vm_mappings.find(&read_range) {
let vm_mapping_range = vm_mapping.range();
if vm_mapping_range.start <= read_start && read_end <= vm_mapping_range.end {
let vm_mapping_offset = read_start - vm_mapping_range.start;
return vm_mapping.read_bytes(vm_mapping_offset, buf);
}
}
@ -431,20 +443,23 @@ impl Vmar_ {
.len()
.checked_add(write_start)
.ok_or_else(|| Error::with_message(Errno::EFAULT, "Arithmetic Overflow"))?;
let write_range = write_start..write_end;
// if the write range is in child vmar
for (child_vmar_base, child_vmar) in &self.inner.lock().child_vmar_s {
let child_vmar_end = *child_vmar_base + child_vmar.size;
if *child_vmar_base <= write_start && write_end <= child_vmar_end {
let child_offset = write_start - *child_vmar_base;
return child_vmar.write(child_offset, buf);
let inner = self.inner.lock();
for child_vmar_ in inner.child_vmar_s.find(&write_range) {
let child_vmar_range = child_vmar_.range();
if child_vmar_range.start <= write_start && write_end <= child_vmar_range.end {
let child_offset = write_start - child_vmar_range.start;
return child_vmar_.write(child_offset, buf);
}
}
// if the write range is in mapped vmo
for (vm_mapping_base, vm_mapping) in &self.inner.lock().vm_mappings {
let vm_mapping_end = *vm_mapping_base + vm_mapping.map_size();
if *vm_mapping_base <= write_start && write_end <= vm_mapping_end {
let vm_mapping_offset = write_start - *vm_mapping_base;
for vm_mapping in inner.vm_mappings.find(&write_range) {
let vm_mapping_range = vm_mapping.range();
if vm_mapping_range.start <= write_start && write_end <= vm_mapping_range.end {
let vm_mapping_offset = write_start - vm_mapping_range.start;
return vm_mapping.write_bytes(vm_mapping_offset, buf);
}
}
@ -503,18 +518,24 @@ impl Vmar_ {
child_size: usize,
align: usize,
) -> Result<(Vaddr, Vaddr)> {
for (region_base, free_region) in &self.inner.lock().free_regions {
if let Some(child_vmar_offset) = child_offset {
// if the offset is set, we should find a free region can satisfy both the offset and size
if *region_base <= child_vmar_offset
&& (child_vmar_offset + child_size) <= (free_region.end())
let inner = self.inner.lock();
if let Some(child_vmar_offset) = child_offset {
// if the offset is set, we should find a free region can satisfy both the offset and size
let child_vmar_range = child_vmar_offset..(child_vmar_offset + child_size);
for free_region in inner.free_regions.find(&child_vmar_range) {
let free_region_range = free_region.range();
if free_region_range.start <= child_vmar_range.start
&& child_vmar_range.end <= free_region_range.end
{
return Ok((*region_base, child_vmar_offset));
return Ok((free_region_range.start, child_vmar_offset));
}
} else {
// else, we find a free region that can satisfy the length and align requirement.
// Here, we use a simple brute-force algorithm to find the first free range that can satisfy.
// FIXME: A randomized algorithm may be more efficient.
}
} else {
// else, we find a free region that can satisfy the length and align requirement.
// Here, we use a simple brute-force algorithm to find the first free range that can satisfy.
// FIXME: A randomized algorithm may be more efficient.
for (region_base, free_region) in &inner.free_regions {
let region_start = free_region.start();
let region_end = free_region.end();
let child_vmar_real_start = region_start.align_up(align);
@ -527,34 +548,27 @@ impl Vmar_ {
return_errno_with_message!(Errno::EACCES, "Cannot find free region for child")
}
fn range(&self) -> Range<usize> {
self.base..(self.base + self.size)
}
fn check_vmo_overwrite(&self, vmo_range: Range<usize>, can_overwrite: bool) -> Result<()> {
let inner = self.inner.lock();
for child_vmar in inner.child_vmar_s.values() {
let child_vmar_range = child_vmar.range();
if is_intersected(&vmo_range, &child_vmar_range) {
return_errno_with_message!(
Errno::EACCES,
"vmo range overlapped with child vmar range"
);
}
if inner
.child_vmar_s
.find(&vmo_range)
.into_iter()
.next()
.is_some()
{
return_errno_with_message!(Errno::EACCES, "vmo range overlapped with child vmar range");
}
if !can_overwrite {
for (child_vmo_base, child_vmo) in &inner.vm_mappings {
let child_vmo_range = *child_vmo_base..*child_vmo_base + child_vmo.map_size();
if is_intersected(&vmo_range, &child_vmo_range) {
debug!("vmo_range = {:x?}", vmo_range);
debug!("child_vmo_range = {:x?}", child_vmo_range);
return_errno_with_message!(
Errno::EACCES,
"vmo range overlapped with another vmo"
);
}
}
if !can_overwrite
&& inner
.vm_mappings
.find(&vmo_range)
.into_iter()
.next()
.is_some()
{
return_errno_with_message!(Errno::EACCES, "vmo range overlapped with another vmo");
}
Ok(())
@ -594,15 +608,17 @@ impl Vmar_ {
let map_range = offset..(offset + map_size);
// If can overwrite, the vmo can cross multiple free regions. We will split each free regions that intersect with the vmo
let mut split_regions = Vec::new();
for (free_region_base, free_region) in &inner.free_regions {
for free_region in inner.free_regions.find(&map_range) {
let free_region_range = free_region.range();
if is_intersected(free_region_range, &map_range) {
split_regions.push(*free_region_base);
if is_intersected(&free_region_range, &map_range) {
split_regions.push(free_region_range.start);
}
}
for region_base in split_regions {
let free_region = inner.free_regions.remove(&region_base).unwrap();
let intersected_range = get_intersected_range(free_region.range(), &map_range);
let intersected_range = get_intersected_range(&free_region.range(), &map_range);
let regions_after_split = free_region.allocate_range(intersected_range);
regions_after_split.into_iter().for_each(|region| {
inner.free_regions.insert(region.start(), region);
@ -618,7 +634,7 @@ impl Vmar_ {
let mut inner = self.inner.lock();
let free_region = inner.free_regions.remove(&free_region_base).unwrap();
let vmo_range = offset..(offset + map_size);
let intersected_range = get_intersected_range(free_region.range(), &vmo_range);
let intersected_range = get_intersected_range(&free_region.range(), &vmo_range);
let regions_after_split = free_region.allocate_range(intersected_range);
regions_after_split.into_iter().for_each(|region| {
inner.free_regions.insert(region.start(), region);
@ -704,11 +720,14 @@ impl Vmar_ {
/// get mapped vmo at given offset
fn get_vm_mapping(&self, offset: Vaddr) -> Result<Arc<VmMapping>> {
for (vm_mapping_base, vm_mapping) in &self.inner.lock().vm_mappings {
if *vm_mapping_base <= offset && offset < *vm_mapping_base + vm_mapping.map_size() {
return Ok(vm_mapping.clone());
}
let inner = self.inner.lock();
let range = offset..offset + 1;
if let Some(vm_mapping) = inner.vm_mappings.find_one(&offset) {
debug_assert!(is_intersected(&vm_mapping.range(), &(offset..offset + 1)));
return Ok(vm_mapping.clone());
}
return_errno_with_message!(Errno::EACCES, "No mapped vmo at this offset");
}
}
@ -739,6 +758,12 @@ pub struct FreeRegion {
range: Range<Vaddr>,
}
impl Interval<usize> for FreeRegion {
fn range(&self) -> Range<usize> {
self.range.clone()
}
}
impl FreeRegion {
pub fn new(range: Range<Vaddr>) -> Self {
Self { range }
@ -756,10 +781,6 @@ impl FreeRegion {
self.range.end - self.range.start
}
pub fn range(&self) -> &Range<usize> {
&self.range
}
/// allocate a range in this free region.
/// The range is ensured to be contained in current region before call this function.
/// The return vector contains regions that are not allocated. Since the allocate_range can be
@ -785,6 +806,7 @@ impl FreeRegion {
}
/// determine whether two ranges are intersected.
/// returns zero if one of the ranges has a length of 0
pub fn is_intersected(range1: &Range<usize>, range2: &Range<usize>) -> bool {
range1.start.max(range2.start) < range1.end.min(range2.end)
}
@ -795,3 +817,60 @@ pub fn get_intersected_range(range1: &Range<usize>, range2: &Range<usize>) -> Ra
debug_assert!(is_intersected(range1, range2));
range1.start.max(range2.start)..range1.end.min(range2.end)
}
impl<'a, V: Interval<Vaddr> + 'a> IntervalSet<'a, Vaddr> for BTreeMap<Vaddr, V> {
type Item = V;
fn find(&'a self, range: &Range<Vaddr>) -> impl IntoIterator<Item = &'a Self::Item> + 'a {
let mut res = Vec::new();
let mut start_cursor = self.lower_bound(core::ops::Bound::Excluded(&range.start));
let start_key = {
start_cursor.move_prev();
if start_cursor.key().is_none()
|| start_cursor.value().unwrap().range().end <= range.start
{
// the start_cursor is pointing to the "ghost" non-element before the first element
// or not intersected
start_cursor.move_next();
}
if start_cursor.key().is_none()
|| start_cursor.value().unwrap().range().start >= range.end
{
// return None if the start_cursor is pointing to the "ghost" non-element after the last element
// or not intersected
return res;
}
start_cursor.key().unwrap()
};
let mut end_cursor = start_cursor.clone();
loop {
if end_cursor.key().is_none() || end_cursor.value().unwrap().range().start >= range.end
{
// the end_cursor is pointing to the "ghost" non-element after the last element
// or not intersected
break;
}
res.push(end_cursor.value().unwrap());
end_cursor.move_next();
}
res
}
fn find_one(&'a self, point: &Vaddr) -> Option<&'a Self::Item> {
let mut cursor = self.lower_bound(core::ops::Bound::Excluded(point));
cursor.move_prev();
if cursor.key().is_none() || cursor.value().unwrap().range().end <= *point {
// the cursor is pointing to the "ghost" non-element before the first element
// or not intersected
cursor.move_next();
}
// return None if the cursor is pointing to the "ghost" non-element after the last element
cursor.key()?;
if cursor.value().unwrap().range().start > *point {
None
} else {
Some(cursor.value().unwrap())
}
}
}

8
services/libs/aster-std/src/vm/vmar/vm_mapping.rs
View File

@ -15,6 +15,8 @@ use crate::vm::perms::VmPerms;
use crate::vm::vmar::Rights;
use crate::vm::vmo::VmoRightsOp;
use super::interval::Interval;
/// A VmMapping represents mapping a vmo into a vmar.
/// A vmar can has multiple VmMappings, which means multiple vmos are mapped to a vmar.
/// A vmo can also contain multiple VmMappings, which means a vmo can be mapped to multiple vmars.
@ -58,6 +60,12 @@ struct VmMappingInner {
page_perms: BTreeMap<usize, VmPerm>,
}
impl Interval<usize> for Arc<VmMapping> {
fn range(&self) -> Range<usize> {
self.map_to_addr()..self.map_to_addr() + self.map_size()
}
}
impl VmMapping {
pub fn build_mapping<R1, R2>(option: VmarMapOptions<R1, R2>) -> Result<Self> {
let VmarMapOptions {