From 8d1dd7a3dc8e882630f0f6d9be0192f70aa824b1 Mon Sep 17 00:00:00 2001
From: Avi Kivity <avi.kivity@gmail.com>
Date: Mon, 31 Dec 2012 16:21:35 +0200
Subject: [PATCH] fs: directory entry cache
Store directory entries in a hash table for future lookup.
---
fs/bootfs.cc | 2 +-
fs/bootfs.hh | 2 +-
fs/fs.cc | 25 +++++++++++++++++++++++++
fs/fs.hh | 14 +++++++++++++-
4 files changed, 40 insertions(+), 3 deletions(-)
diff --git a/fs/bootfs.cc b/fs/bootfs.cc
index 1b563fc44..8159f8d26 100644
--- a/fs/bootfs.cc
+++ b/fs/bootfs.cc
@@ -53,7 +53,7 @@ bootfs::dir::dir(bootfs& fs, std::string path)
{
}
-fileref bootfs::dir::open(std::string name)
+fileref bootfs::dir::do_open(std::string name)
{
return _fs.do_open(_path + name);
}
diff --git a/fs/bootfs.hh b/fs/bootfs.hh
index a3d332eb7..63f29cdc8 100644
--- a/fs/bootfs.hh
+++ b/fs/bootfs.hh
@@ -33,7 +33,7 @@ private:
class bootfs::dir : public ::dir {
public:
dir(bootfs& fs, std::string path);
- virtual fileref open(std::string name);
+ virtual fileref do_open(std::string name);
virtual uint64_t size();
virtual void read(void* buffer, uint64_t offset, uint64_t len);
private:
diff --git a/fs/fs.cc b/fs/fs.cc
index 68c2af78c..2dab7d451 100644
--- a/fs/fs.cc
+++ b/fs/fs.cc
@@ -2,6 +2,18 @@
filesystem* rootfs;
+namespace std {
+
+template <>
+struct hash<file::cache_key> {
+ size_t operator()(file::cache_key k) const {
+ return reinterpret_cast<uintptr_t>(k.first.get())
+ ^ std::hash<std::string>()(k.second);
+ }
+};
+
+}
+
file::file()
: _refs(0)
{
@@ -43,8 +55,21 @@ fileref filesystem::open(std::string name)
return d->open(name.substr(s, name.npos));
}
+fileref dir::open(std::string name)
+{
+ cache_key key(this, name);
+ auto ret = _cache.find(key);
+ if (ret == _cache.end()) {
+ auto f = do_open(name);
+ ret = _cache.insert(cache_type::value_type(key, f)).first;
+ }
+ return ret->second;
+}
+
dirref dir::subdir(std::string name)
{
// trivial implementation, can be overridden
return boost::dynamic_pointer_cast<dir>(open(name));
}
+
+file::cache_type file::_cache;
diff --git a/fs/fs.hh b/fs/fs.hh
index 85d1ccc77..570f35ac9 100644
--- a/fs/fs.hh
+++ b/fs/fs.hh
@@ -4,6 +4,7 @@
#include <string>
#include <cstdint>
#include <boost/intrusive_ptr.hpp>
+#include <unordered_map>
class file;
class dir;
@@ -24,12 +25,23 @@ private:
unsigned _refs; // FIXME: make atomic
friend void intrusive_ptr_add_ref(file* f) { f->ref(); }
friend void intrusive_ptr_release(file* f) { f->unref(); }
+ friend class dir;
+private:
+ typedef std::pair<dirref, std::string> cache_key;
+ // FIXME: an intrusive container
+ typedef std::unordered_map<cache_key, fileref> cache_type;
+ static cache_type _cache;
+ friend struct std::hash<cache_key>;
};
class dir : public file {
public:
- virtual fileref open(std::string name) = 0;
+ fileref open(std::string name);
+ virtual fileref do_open(std::string name) = 0;
dirref subdir(std::string name);
+private:
+ dirref _parent;
+ std::string _name;
};
class filesystem {
--
GitLab