diff --git a/src/Makefile b/src/Makefile index a45002de..6918e927 100644 --- a/src/Makefile +++ b/src/Makefile @@ -61,7 +61,7 @@ QUIET_CC = @printf ' %b %b\n' $(CCCOLOR)CC$(ENDCOLOR) $(SRCCOLOR)$@$(ENDCOLOR QUIET_LINK = @printf ' %b %b\n' $(LINKCOLOR)LINK$(ENDCOLOR) $(BINCOLOR)$@$(ENDCOLOR); endif -OBJ = adlist.o ae.o anet.o dict.o redis.o sds.o zmalloc.o lzf_c.o lzf_d.o pqsort.o zipmap.o sha1.o ziplist.o release.o networking.o util.o object.o db.o replication.o rdb.o t_string.o t_list.o t_set.o t_zset.o t_hash.o config.o aof.o pubsub.o multi.o debug.o sort.o intset.o syncio.o cluster.o crc16.o endian.o slowlog.o scripting.o +OBJ = adlist.o ae.o anet.o dict.o redis.o sds.o zmalloc.o lzf_c.o lzf_d.o pqsort.o zipmap.o sha1.o ziplist.o release.o networking.o util.o object.o db.o replication.o rdb.o t_string.o t_list.o t_set.o t_zset.o t_hash.o config.o aof.o pubsub.o multi.o debug.o sort.o intset.o syncio.o cluster.o crc16.o endian.o slowlog.o scripting.o bio.o BENCHOBJ = ae.o anet.o redis-benchmark.o sds.o adlist.o zmalloc.o CLIOBJ = anet.o sds.o adlist.o redis-cli.o zmalloc.o release.o CHECKDUMPOBJ = redis-check-dump.o lzf_c.o lzf_d.o diff --git a/src/bio.c b/src/bio.c new file mode 100644 index 00000000..fc85afd8 --- /dev/null +++ b/src/bio.c @@ -0,0 +1,107 @@ +/* Background I/O service for Redis. + * + * This file implements operations that we need to perform in the background. + * Currently there is only a single operation, that is a background close(2) + * system call. This is needed as when the process is the last owner of a + * reference to a file closing it means unlinking it, and the deletion of the + * file is slow, blocking the server. + * + * In the future we'll either continue implementing new things we need or + * we'll switch to libeio. However there are probably long term uses for this + * file as we may want to put here Redis specific background tasks (for instance + * it is not impossible that we'll need a non blocking FLUSHDB/FLUSHALL + * implementation). + * + * DESIGN + * ------ + * + * 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. + * 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. + */ + +#include "redis.h" +#include "bio.h" + +static pthread_mutex_t bio_mutex; +static pthread_cond_t bio_condvar; +list *bio_jobs; + +/* 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. */ +} + +void *bioProcessBackgroundJobs(void *arg); + +/* Initialize the background system, spawning the thread. */ +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(); + + /* Set the stack size as by default it may be small in some system */ + pthread_attr_init(&attr); + pthread_attr_getstacksize(&attr); + if (!stacksize) stacksize = 1; /* The world is full of Solaris Fixes */ + 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); + } +} + +void bioCreateBackgroundJob(int type, void *data) { + 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); +} + +void *bioProcessBackgroundJobs(void *arg) { + struct bio_job *job; + + pthread_detach(pthread_self()); + pthread_mutex_lock(&bio_mutex); + 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); + continue; + } + /* Pop the job from the queue. */ + ln = listFirst(bio_jobs); + 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); + + /* Process the job accordingly to its type. */ + if (job->type == REDIS_BIO_CLOSE_FILE) { + close((long)job->data); + } else { + redisPanic("Wrong job type in bioProcessBackgroundJobs()."); + } + zfree(job); + + /* 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); + } +} diff --git a/src/bio.h b/src/bio.h new file mode 100644 index 00000000..3721fa2b --- /dev/null +++ b/src/bio.h @@ -0,0 +1,6 @@ +/* Exported API */ +void bioInit(void); +void bioCreateBackgroundJob(int type, void *data); + +/* Background job opcodes */ +#define REDIS_BIO_CLOSE_FILE 1