#include <UnlikelyLock.h>
Collaboration diagram for UnlikelyLock:
Public Member Functions | |
| bool | enter () |
| void | leave () |
| bool | acquire () |
| void | release () |
Private Attributes | |
| Mutex | m_Lock |
| ConditionVariable | m_Condition |
| uint64_t | m_nReaders |
| bool | m_bActiveWriter |
Detailed Description
An "Unlikely lock" is a lock which normally any number of threads can access concurrently, but when locked, all threads must exit and never reenter.
This is implemented as a simple counting semaphore that starts at zero. Any thread can acquire by adding one to the semaphore. If a thread discovers that the semaphore was over a threshold (100000), it decrements again and returns false.
Thus, the lock can be acquired by adding 100000 to the atomic member, and waiting until the atomic member's value drops to exactly 100000, at which point all threads will have exited.
Definition at line 46 of file UnlikelyLock.h.
Member Function Documentation
| bool UnlikelyLock::acquire | ( | ) |
Locks the lock. Will not return until all other threads have exited the critical region.
Definition at line 53 of file UnlikelyLock.cc.
Referenced by PosixSubsystem::acquire(), PosixSubsystem::addFileDescriptor(), PosixSubsystem::allocateFd(), PosixSubsystem::copyDescriptors(), PosixSubsystem::freeFd(), PosixSubsystem::freeMultipleFds(), PosixSubsystem::getFd(), PosixSubsystem::PosixSubsystem(), and PosixSubsystem::setSignalHandler().
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| bool UnlikelyLock::enter | ( | ) |
Enters the critical section.
- Returns
- True if the lock was able to be acquired, false otherwise.
Definition at line 32 of file UnlikelyLock.cc.
Referenced by PosixSubsystem::getFileDescriptor(), and PosixSubsystem::PosixSubsystem().
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| void UnlikelyLock::leave | ( | ) |
Leaving the critical section.
Definition at line 44 of file UnlikelyLock.cc.
Referenced by PosixSubsystem::getFileDescriptor(), and PosixSubsystem::PosixSubsystem().
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| void UnlikelyLock::release | ( | ) |
Releases the lock.
Definition at line 65 of file UnlikelyLock.cc.
Referenced by PosixSubsystem::addFileDescriptor(), PosixSubsystem::allocateFd(), PosixSubsystem::copyDescriptors(), PosixSubsystem::freeFd(), PosixSubsystem::freeMultipleFds(), PosixSubsystem::getFd(), PosixSubsystem::PosixSubsystem(), PosixSubsystem::release(), and PosixSubsystem::setSignalHandler().
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The documentation for this class was generated from the following files:
