Lock

Ticket spinlock. More...

Collaboration diagram for Lock:

Detailed Description

Ticket spinlock.

Data Structures
struct	lock_t
	A simple ticket lock implementation. More...

Macros
#define	LOCK_DEADLOCK_ITERATIONS   10000000
	Number of iterations before we consider a deadlock to have occurred in lock_acquire. This is only used in debug builds.
#define	LOCK_CANARY   0xDEADBEEF
	Lock canary value to detect memory corruption.
#define	LOCK_SCOPE(lock)
	Acquires a lock for the reminder of the current scope.
#define	LOCK_CREATE()
	Create a lock initializer.

Functions
static void	lock_init (lock_t *lock)
	Initializes a lock.
static void	lock_acquire (lock_t *lock)
	Acquires a lock, blocking until it is available.
static void	lock_release (lock_t *lock)
	Releases a lock.
static void	lock_cleanup (lock_t **lock)

Macro Definition Documentation

LOCK_DEADLOCK_ITERATIONS

#define LOCK_DEADLOCK_ITERATIONS   10000000

Number of iterations before we consider a deadlock to have occurred in lock_acquire. This is only used in debug builds.

Definition at line 25 of file lock.h.

LOCK_CANARY

#define LOCK_CANARY   0xDEADBEEF

Lock canary value to detect memory corruption.

Definition at line 30 of file lock.h.

LOCK_SCOPE

#define LOCK_SCOPE

(

lock

)

Value:

    __attribute__((cleanup(lock_cleanup))) lock_t* CONCAT(l, __COUNTER__) = (lock); \
    lock_acquire((lock))

Acquires a lock for the reminder of the current scope.

Parameters

lock	Pointer to the lock to acquire.

Definition at line 57 of file lock.h.

LOCK_CREATE

#define LOCK_CREATE

(

)

Value:

    (lock_t) \
    { \
        .nextTicket = ATOMIC_VAR_INIT(0), .nowServing = ATOMIC_VAR_INIT(0), .canary = LOCK_CANARY \
    }

Create a lock initializer.

Returns

A lock_t initializer.

Definition at line 68 of file lock.h.

Function Documentation

lock_init()

static void lock_init ( lock_t *  lock )

inlinestatic

Initializes a lock.

Parameters

lock	Pointer to the lock to initialize.

Definition at line 86 of file lock.h.

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lock_acquire()

static void lock_acquire ( lock_t *  lock )

inlinestatic

Acquires a lock, blocking until it is available.

This function disables interrupts on the current CPU. It is not recursive, and attempting to acquire a lock that is already held by the same CPU will result in a deadlock.

Parameters

lock	Pointer to the lock to acquire.

Definition at line 103 of file lock.h.

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lock_release()

static void lock_release ( lock_t *  lock )

inlinestatic

Releases a lock.

This function restores the interrupt state on the current CPU to what it was before the lock was acquired.

Parameters

lock	Pointer to the lock to release.

Definition at line 146 of file lock.h.

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lock_cleanup()

static void lock_cleanup ( lock_t **  lock )

inlinestatic

Definition at line 159 of file lock.h.

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