Commit 7bfe699d authored by John Esmet's avatar John Esmet Committed by Yoni Fogel
Browse files

close[t:4284] the non blocking mutex implementation is now a wrapper of the... 

close[t:4284] the non blocking mutex implementation is now a wrapper of the rwlock implementation. the non blocking mutex api uses only the writer portion of the rwlock api


git-svn-id: file:///svn/toku/tokudb@39143 c7de825b-a66e-492c-adef-691d508d4ae1
parent 2b70bb19

newbrt/nonblocking_mutex.h

+14 −35
Original line number Diff line number Diff line
@@ -11,7 +11,7 @@ 
extern "C" {

#endif



//Use case:

#include "rwlock.h"



//Use case:

// General purpose non blocking mutex with properties:
@@ -24,74 +24,53 @@ extern "C" { 


typedef struct nb_mutex *NB_MUTEX;

struct nb_mutex {

    int writer;                  // the number of writers

    int want_write;              // the number of blocked writers

    toku_pthread_cond_t wait_write;

    struct rwlock lock;

};



// initialize a read write lock



// initialize an nb mutex

static __attribute__((__unused__))

void

nb_mutex_init(NB_MUTEX nb_mutex) {

    int r;

    nb_mutex->writer = nb_mutex->want_write = 0;

    r = toku_pthread_cond_init(&nb_mutex->wait_write, 0); assert(r == 0);

    rwlock_init(&nb_mutex->lock);

}



// destroy a read write lock



static __attribute__((__unused__))

void

nb_mutex_destroy(NB_MUTEX nb_mutex) {

    int r;

    assert(nb_mutex->writer == 0 && nb_mutex->want_write == 0);

    r = toku_pthread_cond_destroy(&nb_mutex->wait_write); assert(r == 0);

    rwlock_destroy(&nb_mutex->lock);

}





// obtain a write lock

// expects: mutex is locked



static inline void nb_mutex_write_lock(NB_MUTEX nb_mutex, toku_pthread_mutex_t *mutex) {

    if (nb_mutex->writer) {

        nb_mutex->want_write++;

        while (nb_mutex->writer) {

            int r = toku_pthread_cond_wait(&nb_mutex->wait_write, mutex); assert(r == 0);

        }

        nb_mutex->want_write--;

    }

    nb_mutex->writer++;

static inline void nb_mutex_write_lock(NB_MUTEX nb_mutex, 

        toku_pthread_mutex_t *mutex) {

    rwlock_write_lock(&nb_mutex->lock, mutex);

}



// release a write lock

// expects: mutex is locked



static inline void nb_mutex_write_unlock(NB_MUTEX nb_mutex) {

    assert(nb_mutex->writer == 1);

    nb_mutex->writer--;

    if (nb_mutex->want_write) {

        int r = toku_pthread_cond_signal(&nb_mutex->wait_write); assert(r == 0);

    } 

    rwlock_write_unlock(&nb_mutex->lock);

}



// returns: the number of writers who are waiting for the lock



static inline int nb_mutex_blocked_writers(NB_MUTEX nb_mutex) {

    return nb_mutex->want_write;

    return rwlock_blocked_writers(&nb_mutex->lock);

}



// returns: the number of writers



static inline int nb_mutex_writers(NB_MUTEX nb_mutex) {

    return nb_mutex->writer;

    return rwlock_writers(&nb_mutex->lock);

}



// returns: the sum of the number of readers, pending readers, writers, and

// pending writers



// returns: the sum of the number of readers, pending readers, 

// writers, and pending writers

static inline int nb_mutex_users(NB_MUTEX nb_mutex) {

    return nb_mutex->writer + nb_mutex->want_write;

    return rwlock_users(&nb_mutex->lock);

}



#if defined(__cplusplus) || defined(__cilkplusplus)