blob: e361881ab9213567756b01d850b813eadb47d0f9 (
plain)
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
|
// @file pagefault.h
/**
* Copyright (C) 2012 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
namespace mongo {
class Record;
class PageFaultException /*: public DBException*/ {
unsigned era;
const Record *r;
public:
PageFaultException(const PageFaultException& rhs) : era(rhs.era), r(rhs.r) { }
explicit PageFaultException(const Record*);
void touch();
};
class PageFaultRetryableSection : boost::noncopyable {
unsigned _laps;
public:
unsigned laps() const { return _laps; }
void didLap() { _laps++; }
PageFaultRetryableSection();
~PageFaultRetryableSection();
};
/**
* this turns off page faults in a scope
* there are just certain arease where its dangerous
* this might mean the code is dangerous anyway....
*/
class NoPageFaultsAllowed : boost::noncopyable {
public:
NoPageFaultsAllowed();
~NoPageFaultsAllowed();
private:
PageFaultRetryableSection* _saved;
};
#if 0
inline void how_to_use_example() {
// ...
{
PageFaultRetryableSection s;
while( 1 ) {
try {
writelock lk; // or readlock
// do work
break;
}
catch( PageFaultException& e ) {
e.touch();
}
}
}
// ...
}
#endif
}
|
