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
|
/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/platform/basic.h"
#include "mongo/db/query/query_yield.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/db/curop.h"
#include "mongo/db/operation_context.h"
#include "mongo/util/fail_point_service.h"
#include "mongo/util/time_support.h"
namespace mongo {
namespace {
MONGO_FAIL_POINT_DEFINE(setYieldAllLocksHang);
MONGO_FAIL_POINT_DEFINE(setYieldAllLocksWait);
} // namespace
// static
void QueryYield::yieldAllLocks(OperationContext* opCtx,
stdx::function<void()> whileYieldingFn,
const NamespaceString& planExecNS) {
// Things have to happen here in a specific order:
// * Release lock mgr locks
// * Go to sleep
// * Call the whileYieldingFn
// * Reacquire lock mgr locks
Locker* locker = opCtx->lockState();
Locker::LockSnapshot snapshot;
// Nothing was unlocked, just return, yielding is pointless.
if (!locker->saveLockStateAndUnlock(&snapshot)) {
return;
}
// Top-level locks are freed, release any potential low-level (storage engine-specific
// locks). If we are yielding, we are at a safe place to do so.
opCtx->recoveryUnit()->abandonSnapshot();
// Track the number of yields in CurOp.
CurOp::get(opCtx)->yielded();
MONGO_FAIL_POINT_BLOCK(setYieldAllLocksHang, config) {
StringData ns{config.getData().getStringField("namespace")};
if (ns.empty() || ns == planExecNS.ns()) {
MONGO_FAIL_POINT_PAUSE_WHILE_SET(setYieldAllLocksHang);
}
}
MONGO_FAIL_POINT_BLOCK(setYieldAllLocksWait, customWait) {
const BSONObj& data = customWait.getData();
BSONElement customWaitNS = data["namespace"];
if (!customWaitNS || planExecNS.ns() == customWaitNS.str()) {
sleepFor(Milliseconds(data["waitForMillis"].numberInt()));
}
}
if (whileYieldingFn) {
whileYieldingFn();
}
UninterruptibleLockGuard noInterrupt(locker);
locker->restoreLockState(opCtx, snapshot);
}
} // namespace mongo
|
