Merge pull request #6909 from mslovy/wip-shared-cache

common: improve shared_cache and simple_cache efficiency with hash table

Reviewed-by: Sage Weil <sage@redhat.com>

2 files changed, 34 insertions, 23 deletions

diff --git a/src/common/shared_cache.hpp b/src/common/shared_cache.hpp
index c55119c02b7..8ff949084a6 100644
--- a/src/common/shared_cache.hpp
+++ b/src/common/shared_cache.hpp
@@ -21,8 +21,9 @@
 #include <utility>
 #include "common/Mutex.h"
 #include "common/Cond.h"
+#include "include/unordered_map.h"
 
-template <class K, class V, class C = std::less<K> >
+template <class K, class V, class C = std::less<K>, class H = std::hash<K> >
 class SharedLRU {
   CephContext *cct;
   typedef ceph::shared_ptr<V> VPtr;
@@ -34,7 +35,7 @@ class SharedLRU {
 public:
   int waiting;
 private:
-  map<K, typename list<pair<K, VPtr> >::iterator, C> contents;
+  ceph::unordered_map<K, typename list<pair<K, VPtr> >::iterator, H> contents;
   list<pair<K, VPtr> > lru;
 
   map<K, pair<WeakVPtr, V*>, C> weak_refs;
@@ -47,7 +48,7 @@ private:
   }
 
   void lru_remove(const K& key) {
-    typename map<K, typename list<pair<K, VPtr> >::iterator, C>::iterator i =
+    typename ceph::unordered_map<K, typename list<pair<K, VPtr> >::iterator, H>::iterator i = 
       contents.find(key);
     if (i == contents.end())
       return;
@@ -57,7 +58,7 @@ private:
   }
 
   void lru_add(const K& key, const VPtr& val, list<VPtr> *to_release) {
-    typename map<K, typename list<pair<K, VPtr> >::iterator, C>::iterator i =
+    typename ceph::unordered_map<K, typename list<pair<K, VPtr> >::iterator, H>::iterator i =
       contents.find(key);
     if (i != contents.end()) {
       lru.splice(lru.begin(), lru, i->second);
@@ -92,7 +93,9 @@ private:
 public:
   SharedLRU(CephContext *cct = NULL, size_t max_size = 20)
     : cct(cct), lock("SharedLRU::lock"), max_size(max_size), 
-      size(0), waiting(0) {}
+      size(0), waiting(0) {
+    contents.rehash(max_size); 
+  }
   
   ~SharedLRU() {
     contents.clear();
@@ -161,8 +164,9 @@ public:
     VPtr val; // release any ref we have after we drop the lock
     {
       Mutex::Locker l(lock);
-      if (weak_refs.count(key)) {
-	val = weak_refs[key].first.lock();
+      typename map<K, pair<WeakVPtr, V*>, C>::iterator i = weak_refs.find(key);
+      if (i != weak_refs.end()) {
+	val = i->second.first.lock();
       }
       lru_remove(key);
     }
@@ -172,11 +176,12 @@ public:
     VPtr val; // release any ref we have after we drop the lock
     {
       Mutex::Locker l(lock);
-      if (weak_refs.count(key)) {
-	val = weak_refs[key].first.lock();
+      typename map<K, pair<WeakVPtr, V*>, C>::iterator i = weak_refs.find(key);
+      if (i != weak_refs.end()) {
+	val = i->second.first.lock();
+        weak_refs.erase(i);
       }
       lru_remove(key);
-      weak_refs.erase(key);
     }
   }
 
diff --git a/src/common/simple_cache.hpp b/src/common/simple_cache.hpp
index 8038306adf8..362763253be 100644
--- a/src/common/simple_cache.hpp
+++ b/src/common/simple_cache.hpp
@@ -20,12 +20,13 @@
 #include <memory>
 #include "common/Mutex.h"
 #include "common/Cond.h"
+#include "include/unordered_map.h"
 
-template <class K, class V, class C = std::less<K> >
+template <class K, class V, class C = std::less<K>, class H = std::hash<K> >
 class SimpleLRU {
   Mutex lock;
   size_t max_size;
-  map<K, typename list<pair<K, V> >::iterator, C> contents;
+  ceph::unordered_map<K, typename list<pair<K, V> >::iterator, H> contents;
   list<pair<K, V> > lru;
   map<K, V, C> pinned;
 
@@ -43,7 +44,9 @@ class SimpleLRU {
   }
 
 public:
-  SimpleLRU(size_t max_size) : lock("SimpleLRU::lock"), max_size(max_size) {}
+  SimpleLRU(size_t max_size) : lock("SimpleLRU::lock"), max_size(max_size) {
+    contents.rehash(max_size);
+  }
 
   void pin(K key, V val) {
     Mutex::Locker l(lock);
@@ -55,16 +58,18 @@ public:
     for (typename map<K, V, C>::iterator i = pinned.begin();
 	 i != pinned.end() && i->first <= e;
 	 pinned.erase(i++)) {
-      if (!contents.count(i->first))
+      typename ceph::unordered_map<K, typename list<pair<K, V> >::iterator, H>::iterator iter =
+        contents.find(i->first);
+      if (iter == contents.end())
 	_add(i->first, i->second);
       else
-	lru.splice(lru.begin(), lru, contents[i->first]);
+	lru.splice(lru.begin(), lru, iter->second);
     }
   }
 
   void clear(K key) {
     Mutex::Locker l(lock);
-    typename map<K, typename list<pair<K, V> >::iterator, C>::iterator i =
+    typename ceph::unordered_map<K, typename list<pair<K, V> >::iterator, H>::iterator i =
       contents.find(key);
     if (i == contents.end())
       return;
@@ -80,15 +85,16 @@ public:
 
   bool lookup(K key, V *out) {
     Mutex::Locker l(lock);
-    typename list<pair<K, V> >::iterator loc = contents.count(key) ?
-      contents[key] : lru.end();
-    if (loc != lru.end()) {
-      *out = loc->second;
-      lru.splice(lru.begin(), lru, loc);
+    typename ceph::unordered_map<K, typename list<pair<K, V> >::iterator, H>::iterator i =
+      contents.find(key);
+    if (i != contents.end()) {
+      *out = i->second->second;
+      lru.splice(lru.begin(), lru, i->second);
       return true;
     }
-    if (pinned.count(key)) {
-      *out = pinned[key];
+    typename map<K, V, C>::iterator i_pinned = pinned.find(key);
+    if (i_pinned != pinned.end()) {
+      *out = i_pinned->second;
       return true;
     }
     return false;