1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
|
// reccache.h
/* CachedBasicRecStore
This is our store which implements a traditional page-cache type of storage
(not memory mapped files).
*/
/* LOCK HIERARCHY
dblock
RecCache::rcmutex
i.e. always lock dblock first if you lock both
*/
#pragma once
#include "reci.h"
#include "recstore.h"
namespace mongo {
class RecCache {
struct Node {
Node(void* _data) : data((char *) _data) { dirty = false; newer = 0; }
~Node() {
free(data);
data = 0;
}
char *data;
DiskLoc loc;
bool dirty;
Node *older, *newer; // lru
};
boost::mutex &rcmutex; // mainly to coordinate with the lazy writer thread
unsigned recsize;
map<DiskLoc, Node*> m; // the cache
Node *newest, *oldest;
unsigned nnodes;
set<DiskLoc> dirtyl;
vector<BasicRecStore*> stores; // DiskLoc::a() indicates the index into this vector
map<string, BasicRecStore*> storesByNsKey; // nskey -> BasicRecStore*
public:
static unsigned MAXNODES;
enum BaseValue { Base = 10000 };
private:
BasicRecStore* _initStore(string fname);
BasicRecStore* initStore(int n);
string findStoreFilename(const char *_ns, bool& found);
void initStoreByNs(const char *ns, const string& nskey);
void closeStore(BasicRecStore *rs);
static string directory();
static string mknskey(const char *ns) {
return directory() + ns;
}
/* get the right file for a given diskloc */
BasicRecStore& store(DiskLoc& d) {
int n = d.a() - Base;
if( (int) stores.size() > n ) {
BasicRecStore *rs = stores[n];
if( rs ) {
assert( rs->fileNumber == n );
return *rs;
}
}
return *initStore(n);
}
BasicRecStore& store(const char *ns) {
string nskey = mknskey(ns);
BasicRecStore *&rs = storesByNsKey[nskey];
if( rs )
return *rs;
initStoreByNs(ns, nskey);
return *rs;
}
void writeDirty( set<DiskLoc>::iterator i, bool rawLog = false );
void writeIfDirty(Node *n);
void touch(Node* n) {
if( n == newest )
return;
if( n == oldest ) {
oldest = oldest->newer;
assert( oldest || nnodes == 1 );
}
if( n->older )
n->older->newer = n->newer;
if( n->newer )
n->newer->older = n->older;
n->newer = 0;
n->older = newest;
newest->newer = n;
newest = n;
}
Node* mkNode() {
Node *n = new Node(calloc(recsize,1)); // calloc is TEMP for testing. change to malloc
n->older = newest;
if( newest )
newest->newer = n;
else {
assert( oldest == 0 );
oldest = n;
}
newest = n;
nnodes++;
return n;
}
fileofs fileOfs(DiskLoc d) {
return ((fileofs) d.getOfs()) * recsize;
}
void dump();
void _ejectOld();
public:
/* all public functions (except constructor) should use the mutex */
RecCache(unsigned recsz) : rcmutex( *( new boost::mutex() ) ), recsize(recsz) {
nnodes = 0;
newest = oldest = 0;
}
/* call this after doing some work, after you are sure you are done with modifications.
we call it from dbunlocking().
*/
void ejectOld() {
if( nnodes > MAXNODES ) // just enough here to be inlineable for speed reasons. _ejectOld does the real work
_ejectOld();
}
/* bg writer thread invokes this */
void writeLazily();
/* Note that this may be called BEFORE the actual writing to the node
takes place. We do flushing later on a dbunlocking() call, which happens
after the writing.
*/
void dirty(DiskLoc d) {
assert( d.a() >= Base );
boostlock lk(rcmutex);
map<DiskLoc, Node*>::iterator i = m.find(d);
if( i != m.end() ) {
Node *n = i->second;
if( !n->dirty ) {
n->dirty = true;
dirtyl.insert(n->loc);
}
}
}
char* get(DiskLoc d, unsigned len) {
assert( d.a() >= Base );
assert( len == recsize );
boostlock lk(rcmutex);
map<DiskLoc, Node*>::iterator i = m.find(d);
if( i != m.end() ) {
touch(i->second);
return i->second->data;
}
Node *n = mkNode();
n->loc = d;
store(d).get(fileOfs(d), n->data, recsize); // could throw exception
m.insert( pair<DiskLoc, Node*>(d, n) );
return n->data;
}
void drop(const char *ns);
DiskLoc insert(const char *ns, const void *obuf, int len, bool god) {
boostlock lk(rcmutex);
BasicRecStore& rs = store(ns);
fileofs o = rs.insert((const char *) obuf, len);
assert( o % recsize == 0 );
fileofs recnum = o / recsize;
massert( "RecCache file too large?", recnum <= 0x7fffffff );
Node *n = mkNode();
memcpy(n->data, obuf, len);
DiskLoc d(rs.fileNumber + Base, (int) recnum);
n->loc = d;
m[d] = n;
return d;
}
void closeFiles(string dbname, string path);
// at termination: write dirty pages and close all files
void closing();
};
extern RecCache theRecCache;
class CachedBasicRecStore : public RecStoreInterface {
public:
virtual char* get(DiskLoc d, unsigned len) {
return theRecCache.get(d, len);
}
virtual DiskLoc insert(const char *ns, const void *obuf, int len, bool god) {
return theRecCache.insert(ns, obuf, len, god);
}
virtual void modified(DiskLoc d) {
theRecCache.dirty(d);
}
/* drop collection */
virtual void drop(const char *ns) {
theRecCache.drop(ns);
}
/* close datafiles associated with the db specified. */
virtual void closeFiles(string dbname, string path) {
theRecCache.closeFiles(dbname, dbpath);
}
};
inline void dbunlocking() {
// dassert( dbMutexInfo.isLocked() );
theRecCache.ejectOld();
}
} /*namespace*/
|
