X-Git-Url: https://git.saurik.com/redis.git/blobdiff_plain/f81a5f54d8e8cac73ea198d5061d7b40d40ee942..0cf10e8e867274397f2b7201e51b00996263a143:/src/bio.c diff --git a/src/bio.c b/src/bio.c index fce0658f..aa2cdf9f 100644 --- a/src/bio.c +++ b/src/bio.c @@ -16,7 +16,14 @@ * ------ * * The design is trivial, we have a structure representing a job to perform - * and a single thread performing all the I/O operations in the queue. + * and a different thread and job queue for every job type. + * Every thread wait for new jobs in its queue, and process every job + * sequentially. + * + * Jobs of the same type are guaranteed to be processed from the least + * recently inserted to the most recently inserted (older jobs processed + * first). + * * Currently there is no way for the creator of the job to be notified about * the completion of the operation, this will only be added when/if needed. */ @@ -24,15 +31,24 @@ #include "redis.h" #include "bio.h" -static pthread_mutex_t bio_mutex; -static pthread_cond_t bio_condvar; -list *bio_jobs; +static pthread_mutex_t bio_mutex[REDIS_BIO_NUM_OPS]; +static pthread_cond_t bio_condvar[REDIS_BIO_NUM_OPS]; +static list *bio_jobs[REDIS_BIO_NUM_OPS]; +/* The following array is used to hold the number of pending jobs for every + * OP type. This allows us to export the bioPendingJobsOfType() API that is + * useful when the main thread wants to perform some operation that may involve + * objects shared with the background thread. The main thread will just wait + * that there are no longer jobs of this type to be executed before performing + * the sensible operation. This data is also useful for reporting. */ +static unsigned long long bio_pending[REDIS_BIO_NUM_OPS]; /* This structure represents a background Job. It is only used locally to this * file as the API deos not expose the internals at all. */ struct bio_job { - int type; /* Job type, for instance BIO_JOB_CLOSE */ - void *data; /* Job specific arguments pointer. */ + time_t time; /* Time at which the job was created. */ + /* Job specific arguments pointers. If we need to pass more than three + * arguments we can just pass a pointer to a structure or alike. */ + void *arg1, *arg2, *arg3; }; void *bioProcessBackgroundJobs(void *arg); @@ -46,10 +62,15 @@ void bioInit(void) { pthread_attr_t attr; pthread_t thread; size_t stacksize; - - pthread_mutex_init(&bio_mutex,NULL); - pthread_cond_init(&bio_condvar,NULL); - bio_jobs = listCreate(); + int j; + + /* Initialization of state vars and objects */ + for (j = 0; j < REDIS_BIO_NUM_OPS; j++) { + pthread_mutex_init(&bio_mutex[j],NULL); + pthread_cond_init(&bio_condvar[j],NULL); + bio_jobs[j] = listCreate(); + bio_pending[j] = 0; + } /* Set the stack size as by default it may be small in some system */ pthread_attr_init(&attr); @@ -58,48 +79,67 @@ void bioInit(void) { while (stacksize < REDIS_THREAD_STACK_SIZE) stacksize *= 2; pthread_attr_setstacksize(&attr, stacksize); - /* Ready to spawn our thread */ - if (pthread_create(&thread,&attr,bioProcessBackgroundJobs,NULL) != 0) { - redisLog(REDIS_WARNING,"Fatal: Can't initialize Background Jobs."); - exit(1); + /* Ready to spawn our threads. We use the single argument the thread + * function accepts in order to pass the job ID the thread is + * responsible of. */ + for (j = 0; j < REDIS_BIO_NUM_OPS; j++) { + void *arg = (void*)(unsigned long) j; + if (pthread_create(&thread,&attr,bioProcessBackgroundJobs,arg) != 0) { + redisLog(REDIS_WARNING,"Fatal: Can't initialize Background Jobs."); + exit(1); + } } } -void bioCreateBackgroundJob(int type, void *data) { +void bioCreateBackgroundJob(int type, void *arg1, void *arg2, void *arg3) { struct bio_job *job = zmalloc(sizeof(*job)); - job->type = type; - job->data = data; - pthread_mutex_lock(&bio_mutex); - listAddNodeTail(bio_jobs,job); - pthread_mutex_unlock(&bio_mutex); + job->time = time(NULL); + job->arg1 = arg1; + job->arg2 = arg2; + job->arg3 = arg3; + pthread_mutex_lock(&bio_mutex[type]); + listAddNodeTail(bio_jobs[type],job); + bio_pending[type]++; + pthread_cond_signal(&bio_condvar[type]); + pthread_mutex_unlock(&bio_mutex[type]); } void *bioProcessBackgroundJobs(void *arg) { struct bio_job *job; - REDIS_NOTUSED(arg); + unsigned long type = (unsigned long) arg; + sigset_t sigset; pthread_detach(pthread_self()); - pthread_mutex_lock(&bio_mutex); + pthread_mutex_lock(&bio_mutex[type]); + /* Block SIGALRM so we are sure that only the main thread will + * receive the watchdog signal. */ + sigemptyset(&sigset); + sigaddset(&sigset, SIGALRM); + if (pthread_sigmask(SIG_BLOCK, &sigset, NULL)) + redisLog(REDIS_WARNING, + "Warning: can't mask SIGALRM in bio.c thread: %s", strerror(errno)); + while(1) { listNode *ln; /* The loop always starts with the lock hold. */ - if (listLength(server.io_newjobs) == 0) { - pthread_cond_wait(&bio_condvar,&bio_mutex); + if (listLength(bio_jobs[type]) == 0) { + pthread_cond_wait(&bio_condvar[type],&bio_mutex[type]); continue; } /* Pop the job from the queue. */ - ln = listFirst(bio_jobs); + ln = listFirst(bio_jobs[type]); job = ln->value; - listDelNode(bio_jobs,ln); /* It is now possible to unlock the background system as we know have * a stand alone job structure to process.*/ - pthread_mutex_unlock(&bio_mutex); + pthread_mutex_unlock(&bio_mutex[type]); /* Process the job accordingly to its type. */ - if (job->type == REDIS_BIO_CLOSE_FILE) { - close((long)job->data); + if (type == REDIS_BIO_CLOSE_FILE) { + close((long)job->arg1); + } else if (type == REDIS_BIO_AOF_FSYNC) { + aof_fsync((long)job->arg1); } else { redisPanic("Wrong job type in bioProcessBackgroundJobs()."); } @@ -107,6 +147,71 @@ void *bioProcessBackgroundJobs(void *arg) { /* Lock again before reiterating the loop, if there are no longer * jobs to process we'll block again in pthread_cond_wait(). */ - pthread_mutex_lock(&bio_mutex); + pthread_mutex_lock(&bio_mutex[type]); + listDelNode(bio_jobs[type],ln); + bio_pending[type]--; + } +} + +/* Return the number of pending jobs of the specified type. */ +unsigned long long bioPendingJobsOfType(int type) { + unsigned long long val; + pthread_mutex_lock(&bio_mutex[type]); + val = bio_pending[type]; + pthread_mutex_unlock(&bio_mutex[type]); + return val; +} + +#if 0 /* We don't use the following code for now, and bioWaitPendingJobsLE + probably needs a rewrite using conditional variables instead of the + current implementation. */ + + +/* Wait until the number of pending jobs of the specified type are + * less or equal to the specified number. + * + * This function may block for long time, it should only be used to perform + * the following tasks: + * + * 1) To avoid that the main thread is pushing jobs of a given time so fast + * that the background thread can't process them at the same speed. + * So before creating a new job of a given type the main thread should + * call something like: bioWaitPendingJobsLE(job_type,10000); + * 2) In order to perform special operations that make it necessary to be sure + * no one is touching shared resourced in the background. + */ +void bioWaitPendingJobsLE(int type, unsigned long long num) { + unsigned long long iteration = 0; + + /* We poll the jobs queue aggressively to start, and gradually relax + * the polling speed if it is going to take too much time. */ + while(1) { + iteration++; + if (iteration > 1000 && iteration <= 10000) { + usleep(100); + } else if (iteration > 10000) { + usleep(1000); + } + if (bioPendingJobsOfType(type) <= num) break; } } + +/* Return the older job of the specified type. */ +time_t bioOlderJobOfType(int type) { + time_t time; + listNode *ln; + struct bio_job *job; + + pthread_mutex_lock(&bio_mutex[type]); + ln = listFirst(bio_jobs[type]); + if (ln == NULL) { + pthread_mutex_unlock(&bio_mutex[type]); + return 0; + } + job = ln->value; + time = job->time; + pthread_mutex_unlock(&bio_mutex[type]); + return time; +} + +#endif