src/backup/dynamic_index.rs: Add LruCache for chunks.

In order to improve non-sequential reads of chunks as e.g. in FUSE.

Signed-off-by: Christian Ebner <c.ebner@proxmox.com>
This commit is contained in:
Christian Ebner 2020-02-27 15:56:28 +01:00 committed by Dietmar Maurer
parent 35ddf0b419
commit 536683e73b
2 changed files with 27 additions and 9 deletions

View File

@ -266,6 +266,19 @@ pub struct BufferedDynamicReader<S> {
buffered_chunk_idx: usize,
buffered_chunk_start: u64,
read_offset: u64,
lru_cache: crate::tools::lru_cache::LruCache<usize, (u64, u64, Vec<u8>)>,
}
struct ChunkCacher<'a, S> {
store: &'a mut S,
index: &'a DynamicIndexReader,
}
impl<'a, S: ReadChunk> crate::tools::lru_cache::Cacher<usize, (u64, u64, Vec<u8>)> for ChunkCacher<'a, S> {
fn fetch(&mut self, index: usize) -> Result<Option<(u64, u64, Vec<u8>)>, failure::Error> {
let (start, end, digest) = self.index.chunk_info(index)?;
self.store.read_chunk(&digest).and_then(|data| Ok(Some((start, end, data))))
}
}
impl<S: ReadChunk> BufferedDynamicReader<S> {
@ -279,6 +292,7 @@ impl<S: ReadChunk> BufferedDynamicReader<S> {
buffered_chunk_idx: 0,
buffered_chunk_start: 0,
read_offset: 0,
lru_cache: crate::tools::lru_cache::LruCache::new(32),
}
}
@ -287,27 +301,29 @@ impl<S: ReadChunk> BufferedDynamicReader<S> {
}
fn buffer_chunk(&mut self, idx: usize) -> Result<(), Error> {
let index = &self.index;
let (start, end, digest) = index.chunk_info(idx)?;
let (start, end, data) = self.lru_cache.access(
idx,
&mut ChunkCacher {
store: &mut self.store,
index: &self.index,
},
)?.ok_or_else(|| format_err!("chunk not found by cacher"))?;
// fixme: avoid copy
let data = self.store.read_chunk(&digest)?;
if (end - start) != data.len() as u64 {
if (*end - *start) != data.len() as u64 {
bail!(
"read chunk with wrong size ({} != {}",
(end - start),
(*end - *start),
data.len()
);
}
// fixme: avoid copy
self.read_buffer.clear();
self.read_buffer.extend_from_slice(&data);
self.buffered_chunk_idx = idx;
self.buffered_chunk_start = start as u64;
self.buffered_chunk_start = *start;
//println!("BUFFER {} {}", self.buffered_chunk_start, end);
Ok(())
}

View File

@ -100,6 +100,8 @@ pub struct LruCache<K, V> {
_marker: PhantomData<Box<CacheNode<K, V>>>,
}
unsafe impl<K, V> Send for LruCache<K, V> {}
impl<K: std::cmp::Eq + std::hash::Hash + Copy, V> LruCache<K, V> {
/// Create LRU cache instance which holds up to `capacity` nodes at once.
pub fn new(capacity: usize) -> Self {