[space_map (rust)] Do not reset search position

This commit is contained in:
Ming-Hung Tsai 2021-06-04 18:42:44 +08:00
parent 88e7f8fd69
commit 9e061a03a8

View File

@ -24,9 +24,16 @@ pub trait SpaceMap {
Ok(old == 1)
}
/// Finds a block with a zero reference count. Increments the
/// count.
/// Finds a block with a zero reference count. Increments the count.
/// Returns Ok(None) if no free block (ENOSPC)
/// Returns Err on fatal error
fn alloc(&mut self) -> Result<Option<u64>>;
/// Finds a free block within the range
fn find_free(&mut self, begin: u64, end: u64) -> Result<Option<u64>>;
/// Returns the position where allocation starts
fn get_alloc_begin(&self) -> Result<u64>;
}
pub type ASpaceMap = Arc<Mutex<dyn SpaceMap + Sync + Send>>;
@ -35,7 +42,7 @@ pub type ASpaceMap = Arc<Mutex<dyn SpaceMap + Sync + Send>>;
pub struct CoreSpaceMap<T> {
nr_allocated: u64,
first_free: u64,
alloc_begin: u64,
counts: Vec<T>,
}
@ -46,7 +53,7 @@ where
pub fn new(nr_entries: u64) -> CoreSpaceMap<V> {
CoreSpaceMap {
nr_allocated: 0,
first_free: 0,
alloc_begin: 0,
counts: vec![V::default(); nr_entries as usize],
}
}
@ -77,9 +84,6 @@ where
self.nr_allocated += 1;
} else if old != V::from(0u8) && v == 0 {
self.nr_allocated -= 1;
if b < self.first_free {
self.first_free = b;
}
}
Ok(old.into())
@ -99,18 +103,33 @@ where
}
fn alloc(&mut self) -> Result<Option<u64>> {
for b in self.first_free..(self.counts.len() as u64) {
if self.counts[b as usize] == V::from(0u8) {
self.counts[b as usize] = V::from(1u8);
self.first_free = b + 1;
self.nr_allocated += 1;
return Ok(Some(b));
let mut b = self.find_free(self.alloc_begin, self.counts.len() as u64)?;
if b.is_none() {
b = self.find_free(0, self.alloc_begin)?;
if b.is_none() {
return Ok(None);
}
}
self.first_free = self.counts.len() as u64;
self.counts[b.unwrap() as usize] = V::from(1u8);
self.nr_allocated += 1;
self.alloc_begin = b.unwrap() + 1;
Ok(b)
}
fn find_free(&mut self, begin: u64, end: u64) -> Result<Option<u64>> {
for b in begin..end {
if self.counts[b as usize] == V::from(0u8) {
return Ok(Some(b));
}
}
Ok(None)
}
fn get_alloc_begin(&self) -> Result<u64> {
Ok(self.alloc_begin as u64)
}
}
pub fn core_sm(nr_entries: u64, max_count: u32) -> Arc<Mutex<dyn SpaceMap + Send + Sync>> {
@ -150,7 +169,7 @@ pub fn clone_space_map(src: &dyn SpaceMap) -> Result<Box<dyn SpaceMap>> {
// aren't interested in counting how many times we've visited.
pub struct RestrictedSpaceMap {
nr_allocated: u64,
first_free: usize,
alloc_begin: usize,
counts: FixedBitSet,
}
@ -159,7 +178,7 @@ impl RestrictedSpaceMap {
RestrictedSpaceMap {
nr_allocated: 0,
counts: FixedBitSet::with_capacity(nr_entries as usize),
first_free: 0,
alloc_begin: 0,
}
}
}
@ -192,9 +211,6 @@ impl SpaceMap for RestrictedSpaceMap {
} else {
if old {
self.nr_allocated -= 1;
if b < self.first_free as u64 {
self.first_free = b as usize;
}
}
self.counts.set(b as usize, false);
}
@ -213,17 +229,33 @@ impl SpaceMap for RestrictedSpaceMap {
}
fn alloc(&mut self) -> Result<Option<u64>> {
for b in self.first_free..self.counts.len() {
if !self.counts.contains(b) {
self.counts.insert(b);
self.first_free = b + 1;
return Ok(Some(b as u64));
let mut b = self.find_free(self.alloc_begin as u64, self.counts.len() as u64)?;
if b.is_none() {
b = self.find_free(0, self.alloc_begin as u64)?;
if b.is_none() {
return Ok(None);
}
}
self.first_free = self.counts.len();
self.counts.insert(b.unwrap() as usize);
self.nr_allocated += 1;
self.alloc_begin = b.unwrap() as usize + 1;
Ok(b)
}
fn find_free(&mut self, begin: u64, end: u64) -> Result<Option<u64>> {
for b in begin..end {
if !self.counts.contains(b as usize) {
return Ok(Some(b));
}
}
Ok(None)
}
fn get_alloc_begin(&self) -> Result<u64> {
Ok(self.alloc_begin as u64)
}
}
//------------------------------------------