Using an LruCache instead of a HashMap for loaded pages in a tag

pmeunier

Dec 10, 2021, 1:50 PM

AETYXHGO4N5PURYZT7Z5UZDGLAN7CD6JESLFAASLYFEXZKWSFE7AC

Dependencies

• [2] N3X5YP7P Adding tag/txn.rs, now that the parser allows it

Change contents

• edit in libpijul/src/tag/txn.rs at line 3
  [2.98]→[2.98:148](∅→∅)
  − use std::collections::{hash_map::Entry, HashMap};
• edit in libpijul/src/tag/txn.rs at line 4
  [2.170]

  [2.170]
  +

  + /// Size of the LRU cache.

  + const CACHE_SIZE: usize = 1024;
• replacement in libpijul/src/tag/txn.rs at line 34
  [2.788]→[2.788:856](∅→∅)
  − loaded: Mutex<HashMap<u64, Box<[u8; crate::tag::BLOCK_SIZE]>>>,
  [2.788]

  [2.856]
  + loaded: Mutex<lru_cache::LruCache<u64, Box<[u8; crate::tag::BLOCK_SIZE]>>>,
• replacement in libpijul/src/tag/txn.rs at line 53
  [2.1336]→[2.1336:1412](∅→∅)
  − pub fn new<P: AsRef<std::path::Path>>(p: P) -> Result<Self, TagError> {
  [2.1336]

  [2.1412]
  + pub fn new<P: AsRef<std::path::Path>>(p: P, h: &Hash) -> Result<Self, TagError> {
• replacement in libpijul/src/tag/txn.rs at line 57
  [2.1581]→[2.1581:1655](∅→∅)
  − let header: crate::tag::FileHeader = bincode::deserialize(&off)?;
  [2.1581]

  [2.1655]
  + let header: crate::tag::FileHeader = bincode::deserialize(&off).map_err(TagError::BincodeDe)?;

  + let mut ch = OpenTagFile {

  + file,

  + header

  + };

  + ch.check(h)?;

  + ch.file.seek(SeekFrom::Start(off.len() as u64))?;
• replacement in libpijul/src/tag/txn.rs at line 65
  [2.1723]→[2.1723:1777](∅→∅)
  − r: file,

  − off: header.channel,
  [2.1723]

  [2.1777]
  + r: ch.file,

  + off: ch.header.channel,
• replacement in libpijul/src/tag/txn.rs at line 69
  [2.1811]→[2.1811:1879](∅→∅)
  − header,

  − loaded: Mutex::new(HashMap::new()),
  [2.1811]

  [2.1879]
  + header: ch.header,

  + loaded: Mutex::new(lru_cache::LruCache::new(CACHE_SIZE)),
• replacement in libpijul/src/tag/txn.rs at line 85
  [2.2328]→[2.2328:2869](∅→∅)
  − let p = match self.loaded.lock().unwrap().entry(off_aligned) {

  − Entry::Occupied(mut e) => unsafe {

  − e.get_mut().as_mut_ptr().add((off - off_aligned) as usize)

  − },

  − Entry::Vacant(e) => {

  − let mut buf = Box::new([0; crate::tag::BLOCK_SIZE]);

  − self.s

  − .lock()

  − .unwrap()

  − .decompress(&mut buf[..], off_aligned)?;

  − unsafe { e.insert(buf).as_mut_ptr().add((off - off_aligned) as usize) }
  [2.2328]

  [2.2869]
  + let mut l = self.loaded.lock().unwrap();

  + let p = if let Some(p) = l.get_mut(&off_aligned) {

  + unsafe {

  + p.as_mut_ptr().add((off - off_aligned) as usize)
• edit in libpijul/src/tag/txn.rs at line 90
  [2.2883]

  [2.2883]
  + } else {

  + let mut buf = Box::new([0; crate::tag::BLOCK_SIZE]);

  + self.s

  + .lock()

  + .unwrap()

  + .decompress(&mut buf[..], off_aligned)?;

  + let p = unsafe {

  + buf.as_mut_ptr().add((off - off_aligned) as usize)

  + };

  + l.insert(off_aligned, buf);

  + p