X-Git-Url: https://git.saurik.com/redis.git/blobdiff_plain/133cf28ee8ac01f6a830fd55d9af281b7f62e3f3..3f7b2b1f300e6d0441f420fcb51c253b10631cfa:/src/dscache.c diff --git a/src/dscache.c b/src/dscache.c index 1f283b5b..46300e63 100644 --- a/src/dscache.c +++ b/src/dscache.c @@ -23,76 +23,29 @@ * longer relevant with the new design. Here as a checklist to see if * some old ideas still apply. * - * - The WATCH helper will be used to signal the cache system - * we need to flush a given key/dbid into disk, adding this key/dbid - * pair into a server.ds_cache_dirty linked list AND hash table (so that we - * don't add the same thing multiple times). - * - * - cron() checks if there are elements on this list. When there are things - * to flush, we create an IO Job for the I/O thread. - * NOTE: We disalbe object sharing when server.ds_enabled == 1 so objects - * that are referenced an IO job for flushing on disk are marked as - * o->storage == REDIS_DS_SAVING. - * - * - This is what we do on key lookup: - * 1) The key already exists in memory. object->storage == REDIS_DS_MEMORY - * or it is object->storage == REDIS_DS_DIRTY: - * We don't do nothing special, lookup, return value object pointer. - * 2) The key is in memory but object->storage == REDIS_DS_SAVING. - * When this happens we block waiting for the I/O thread to process - * this object. Then continue. - * 3) The key is not in memory. We block to load the key from disk. - * Of course the key may not be present at all on the disk store as well, - * in such case we just detect this condition and continue, returning - * NULL from lookup. - * - * - Preloading of needed keys: - * 1) As it was done with VM, also with this new system we try preloading - * keys a client is going to use. We block the client, load keys - * using the I/O thread, unblock the client. Same code as VM more or less. - * - * - Reclaiming memory. - * In cron() we detect our memory limit was reached. What we - * do is deleting keys that are REDIS_DS_MEMORY, using LRU. - * - * If this is not enough to return again under the memory limits we also - * start to flush keys that need to be synched on disk synchronously, - * removing it from the memory. We do this blocking as memory limit is a - * much "harder" barrirer in the new design. - * - * - IO thread operations are no longer stopped for sync loading/saving of - * things. When a key is found to be in the process of being saved - * we simply wait for the IO thread to end its work. - * - * Otherwise if there is to load a key without any IO thread operation - * just started it is blocking-loaded in the lookup function. - * * - What happens when an object is destroyed? * - * If o->storage == REDIS_DS_MEMORY then we simply destory the object. - * If o->storage == REDIS_DS_DIRTY we can still remove the object. It had - * changes not flushed on disk, but is being removed so - * who cares. - * if o->storage == REDIS_DS_SAVING then the object is being saved so - * it is impossible that its refcount == 1, must be at - * least two. When the object is saved the storage will - * be set back to DS_MEMORY. - * - * - What happens when keys are deleted? + * If the object is destroyed since semantically it was deleted or + * replaced with something new, we don't care if there was a SAVE + * job pending for it. Anyway when the IO JOb will be created we'll get + * the pointer of the current value. * - * We simply schedule a key flush operation as usually, but when the - * IO thread will be created the object pointer will be set to NULL - * so the IO thread will know that the work to do is to delete the key - * from the disk store. + * If the object is already a REDIS_IO_SAVEINPROG object, then it is + * impossible that we get a decrRefCount() that will reach refcount of zero + * since the object is both in the dataset and in the io job entry. * * - What happens with MULTI/EXEC? * - * Good question. + * Good question. Without some kind of versioning with a global counter + * it is not possible to have trasactions on disk, but they are still + * useful since from the point of view of memory and client bugs it is + * a protection anyway. Also it's useful for WATCH. * - * - If dsSet() fails on the write thread log the error and reschedule the - * key for flush. + * Btw there is to check what happens when WATCH gets combined to keys + * that gets removed from the object cache. Should be save but better + * to check. * - * - Check why INCR will not update the LRU info for the object. + * - Check if/why INCR will not update the LRU info for the object. * * - Fix/Check the following race condition: a key gets a DEL so there is * a write operation scheduled against this key. Later the same key will @@ -114,7 +67,22 @@ * not marked as cacheKeyDoesNotExist(), otherwise, again, we can load * data from disk that should instead be deleted. * - * - dsSet() use rename(2) in order to avoid corruptions. + * - dsSet() should use rename(2) in order to avoid corruptions. + * + * - Don't add a LOAD if there is already a LOADINPROGRESS, or is this + * impossible since anyway the io_keys stuff will work as lock? + * + * - Serialize special encoded things in a raw form. + * + * - When putting IO read operations on top of the queue, do this only if + * the already-on-top operation is not a save or if it is a save that + * is scheduled for later execution. If there is a save that is ready to + * fire, let's insert the load operation just before the first save that + * is scheduled for later exection for instance. + * + * - Support MULTI/EXEC transactions via a journal file, that is played on + * startup to check if there is cleanup to do. This way we can implement + * transactions with our simple file based KV store. */ /* Virtual Memory is composed mainly of two subsystems: @@ -139,6 +107,8 @@ */ void spawnIOThread(void); +int cacheScheduleIOPushJobs(int flags); +int processActiveIOJobs(int max); /* =================== Virtual Memory - Blocking Side ====================== */ @@ -162,6 +132,7 @@ void dsInit(void) { server.io_ready_clients = listCreate(); pthread_mutex_init(&server.io_mutex,NULL); pthread_cond_init(&server.io_condvar,NULL); + pthread_mutex_init(&server.bgsavethread_mutex,NULL); server.io_active_threads = 0; if (pipe(pipefds) == -1) { redisLog(REDIS_WARNING,"Unable to intialized DS: pipe(2): %s. Exiting." @@ -214,8 +185,7 @@ int cacheFreeOneEntry(void) { * are swappable objects */ int maxtries = 100; - if (dictSize(db->dict) == 0) continue; - for (i = 0; i < 5; i++) { + for (i = 0; i < 5 && dictSize(db->dict); i++) { dictEntry *de; double swappability; robj keyobj; @@ -242,10 +212,17 @@ int cacheFreeOneEntry(void) { } } if (best == NULL) { - /* FIXME: If there are objects marked as DS_DIRTY or DS_SAVING - * let's wait for this objects to be clear and retry... - * - * Object cache vm limit is considered an hard limit. */ + /* Not able to free a single object? we should check if our + * IO queues have stuff in queue, and try to consume the queue + * otherwise we'll use an infinite amount of memory if changes to + * the dataset are faster than I/O */ + if (listLength(server.cache_io_queue) > 0) { + redisLog(REDIS_DEBUG,"--- Busy waiting IO to reclaim memory"); + cacheScheduleIOPushJobs(REDIS_IO_ASAP); + processActiveIOJobs(1); + return REDIS_OK; + } + /* Nothing to free at all... */ return REDIS_ERR; } key = dictGetEntryKey(best); @@ -263,13 +240,6 @@ int cacheFreeOneEntry(void) { return REDIS_OK; } -/* Return true if it's safe to swap out objects in a given moment. - * Basically we don't want to swap objects out while there is a BGSAVE - * or a BGAEOREWRITE running in backgroud. */ -int dsCanTouchDiskStore(void) { - return (server.bgsavechildpid == -1 && server.bgrewritechildpid == -1); -} - /* ==================== Disk store negative caching ======================== * * When disk store is enabled, we need negative caching, that is, to remember @@ -303,6 +273,38 @@ void cacheSetKeyDoesNotExist(redisDb *db, robj *key) { } } +/* Remove one entry from negative cache using approximated LRU. */ +int negativeCacheEvictOneEntry(void) { + struct dictEntry *de; + robj *best = NULL; + redisDb *best_db = NULL; + time_t time, best_time = 0; + int j; + + for (j = 0; j < server.dbnum; j++) { + redisDb *db = server.db+j; + int i; + + if (dictSize(db->io_negcache) == 0) continue; + for (i = 0; i < 3; i++) { + de = dictGetRandomKey(db->io_negcache); + time = (time_t) dictGetEntryVal(de); + + if (best == NULL || time < best_time) { + best = dictGetEntryKey(de); + best_db = db; + best_time = time; + } + } + } + if (best) { + dictDelete(best_db->io_negcache,best); + return REDIS_OK; + } else { + return REDIS_ERR; + } +} + /* ================== Disk store cache - Threaded I/O ====================== */ void freeIOJob(iojob *j) { @@ -314,7 +316,14 @@ void freeIOJob(iojob *j) { /* Every time a thread finished a Job, it writes a byte into the write side * of an unix pipe in order to "awake" the main thread, and this function - * is called. */ + * is called. + * + * If privdata == NULL the function will try to put more jobs in the queue + * of IO jobs to process as more room is made. privdata is equal to NULL + * when the function is called from the event loop, so we want to push + * more IO jobs in the queue. Instead when the function is called by + * other functions that want to create a write-barrier to avoid race + * conditions we don't push new jobs in the queue. */ void vmThreadedIOCompletedJob(aeEventLoop *el, int fd, void *privdata, int mask) { @@ -322,7 +331,6 @@ void vmThreadedIOCompletedJob(aeEventLoop *el, int fd, void *privdata, int retval, processed = 0, toprocess = -1; REDIS_NOTUSED(el); REDIS_NOTUSED(mask); - REDIS_NOTUSED(privdata); /* For every byte we read in the read side of the pipe, there is one * I/O job completed to process. */ @@ -359,23 +367,28 @@ void vmThreadedIOCompletedJob(aeEventLoop *el, int fd, void *privdata, if (j->expire != -1) setExpire(j->db,j->key,j->expire); } } else { - /* The key does not exist. Create a negative cache entry - * for this key. */ - cacheSetKeyDoesNotExist(j->db,j->key); + /* Key not found on disk. If it is also not in memory + * as a cached object, nor there is a job writing it + * in background, we are sure the key does not exist + * currently. + * + * So we set a negative cache entry avoiding that the + * resumed client will block load what does not exist... */ + if (dictFind(j->db->dict,j->key->ptr) == NULL && + (cacheScheduleIOGetFlags(j->db,j->key) & + (REDIS_IO_SAVE|REDIS_IO_SAVEINPROG)) == 0) + { + cacheSetKeyDoesNotExist(j->db,j->key); + } } cacheScheduleIODelFlag(j->db,j->key,REDIS_IO_LOADINPROG); handleClientsBlockedOnSwappedKey(j->db,j->key); - freeIOJob(j); } else if (j->type == REDIS_IOJOB_SAVE) { - if (j->val) { - cacheSetKeyMayExist(j->db,j->key); - } else { - cacheSetKeyDoesNotExist(j->db,j->key); - } cacheScheduleIODelFlag(j->db,j->key,REDIS_IO_SAVEINPROG); - freeIOJob(j); } + freeIOJob(j); processed++; + if (privdata == NULL) cacheScheduleIOPushJobs(0); if (processed == toprocess) return; } if (retval < 0 && errno != EAGAIN) { @@ -397,6 +410,7 @@ void *IOThreadEntryPoint(void *arg) { iojob *j; listNode *ln; REDIS_NOTUSED(arg); + long long start; pthread_detach(pthread_self()); lockThreadedIO(); @@ -404,10 +418,13 @@ void *IOThreadEntryPoint(void *arg) { /* Get a new job to process */ if (listLength(server.io_newjobs) == 0) { /* Wait for more work to do */ + redisLog(REDIS_DEBUG,"[T] wait for signal"); pthread_cond_wait(&server.io_condvar,&server.io_mutex); + redisLog(REDIS_DEBUG,"[T] signal received"); continue; } - redisLog(REDIS_DEBUG,"%ld IO jobs to process", + start = ustime(); + redisLog(REDIS_DEBUG,"[T] %ld IO jobs to process", listLength(server.io_newjobs)); ln = listFirst(server.io_newjobs); j = ln->value; @@ -417,7 +434,7 @@ void *IOThreadEntryPoint(void *arg) { ln = listLast(server.io_processing); /* We use ln later to remove it */ unlockThreadedIO(); - redisLog(REDIS_DEBUG,"Thread %ld: new job type %s: %p about key '%s'", + redisLog(REDIS_DEBUG,"[T] %ld: new job type %s: %p about key '%s'", (long) pthread_self(), (j->type == REDIS_IOJOB_LOAD) ? "load" : "save", (void*)j, (char*)j->key->ptr); @@ -430,22 +447,25 @@ void *IOThreadEntryPoint(void *arg) { if (j->val) j->expire = expire; } else if (j->type == REDIS_IOJOB_SAVE) { if (j->val) { - dsSet(j->db,j->key,j->val); + dsSet(j->db,j->key,j->val,j->expire); } else { dsDel(j->db,j->key); } } /* Done: insert the job into the processed queue */ - redisLog(REDIS_DEBUG,"Thread %ld completed the job: %p (key %s)", + redisLog(REDIS_DEBUG,"[T] %ld completed the job: %p (key %s)", (long) pthread_self(), (void*)j, (char*)j->key->ptr); + redisLog(REDIS_DEBUG,"[T] lock IO"); lockThreadedIO(); + redisLog(REDIS_DEBUG,"[T] IO locked"); listDelNode(server.io_processing,ln); listAddNodeTail(server.io_processed,j); /* Signal the main thread there is new stuff to process */ redisAssert(write(server.io_ready_pipe_write,"x",1) == 1); + redisLog(REDIS_DEBUG,"TIME (%c): %lld\n", j->type == REDIS_IOJOB_LOAD ? 'L' : 'S', ustime()-start); } /* never reached, but that's the full pattern... */ unlockThreadedIO(); @@ -471,57 +491,95 @@ void spawnIOThread(void) { server.io_active_threads++; } -/* Wait that all the pending IO Jobs are processed */ -void waitEmptyIOJobsQueue(void) { - while(1) { +/* Wait that up to 'max' pending IO Jobs are processed by the I/O thread. + * From our point of view an IO job processed means that the count of + * server.io_processed must increase by one. + * + * If max is -1, all the pending IO jobs will be processed. + * + * Returns the number of IO jobs processed. + * + * NOTE: while this may appear like a busy loop, we are actually blocked + * by IO since we continuously acquire/release the IO lock. */ +int processActiveIOJobs(int max) { + int processed = 0; + + while(max == -1 || max > 0) { int io_processed_len; + redisLog(REDIS_DEBUG,"[P] lock IO"); lockThreadedIO(); + redisLog(REDIS_DEBUG,"Waiting IO jobs processing: new:%d proessing:%d processed:%d",listLength(server.io_newjobs),listLength(server.io_processing),listLength(server.io_processed)); + if (listLength(server.io_newjobs) == 0 && listLength(server.io_processing) == 0) { + /* There is nothing more to process */ + redisLog(REDIS_DEBUG,"[P] Nothing to process, unlock IO, return"); unlockThreadedIO(); - return; + break; } + +#if 1 /* If there are new jobs we need to signal the thread to - * process the next one. */ - redisLog(REDIS_DEBUG,"waitEmptyIOJobsQueue: new %d, processing %d", + * process the next one. FIXME: drop this if useless. */ + redisLog(REDIS_DEBUG,"[P] waitEmptyIOJobsQueue: new %d, processing %d, processed %d", listLength(server.io_newjobs), - listLength(server.io_processing)); - /* + listLength(server.io_processing), + listLength(server.io_processed)); + if (listLength(server.io_newjobs)) { + redisLog(REDIS_DEBUG,"[P] There are new jobs, signal"); pthread_cond_signal(&server.io_condvar); } - */ - /* While waiting for empty jobs queue condition we post-process some - * finshed job, as I/O threads may be hanging trying to write against - * the io_ready_pipe_write FD but there are so much pending jobs that - * it's blocking. */ +#endif + + /* Check if we can process some finished job */ io_processed_len = listLength(server.io_processed); + redisLog(REDIS_DEBUG,"[P] Unblock IO"); unlockThreadedIO(); + redisLog(REDIS_DEBUG,"[P] Wait"); + usleep(10000); if (io_processed_len) { vmThreadedIOCompletedJob(NULL,server.io_ready_pipe_read, (void*)0xdeadbeef,0); - usleep(1000); /* 1 millisecond */ - } else { - usleep(10000); /* 10 milliseconds */ + processed++; + if (max != -1) max--; } } + return processed; } -/* Process all the IO Jobs already completed by threads but still waiting - * processing from the main thread. */ -void processAllPendingIOJobs(void) { - while(1) { +void waitEmptyIOJobsQueue(void) { + processActiveIOJobs(-1); +} + +/* Process up to 'max' IO Jobs already completed by threads but still waiting + * processing from the main thread. + * + * If max == -1 all the pending jobs are processed. + * + * The number of processed jobs is returned. */ +int processPendingIOJobs(int max) { + int processed = 0; + + while(max == -1 || max > 0) { int io_processed_len; lockThreadedIO(); io_processed_len = listLength(server.io_processed); unlockThreadedIO(); - if (io_processed_len == 0) return; + if (io_processed_len == 0) break; vmThreadedIOCompletedJob(NULL,server.io_ready_pipe_read, (void*)0xdeadbeef,0); + if (max != -1) max--; + processed++; } + return processed; +} + +void processAllPendingIOJobs(void) { + processPendingIOJobs(-1); } /* This function must be called while with threaded IO locked */ @@ -529,11 +587,23 @@ void queueIOJob(iojob *j) { redisLog(REDIS_DEBUG,"Queued IO Job %p type %d about key '%s'\n", (void*)j, j->type, (char*)j->key->ptr); listAddNodeTail(server.io_newjobs,j); - if (server.io_active_threads < server.vm_max_threads) - spawnIOThread(); } -void dsCreateIOJob(int type, redisDb *db, robj *key, robj *val) { +/* Consume all the IO scheduled operations, and all the thread IO jobs + * so that eventually the state of diskstore is a point-in-time snapshot. + * + * This is useful when we need to BGSAVE with diskstore enabled. */ +void cacheForcePointInTime(void) { + redisLog(REDIS_NOTICE,"Diskstore: synching on disk to reach point-in-time state."); + while (listLength(server.cache_io_queue) != 0) { + cacheScheduleIOPushJobs(REDIS_IO_ASAP); + processActiveIOJobs(1); + } + waitEmptyIOJobsQueue(); + processAllPendingIOJobs(); +} + +void cacheCreateIOJob(int type, redisDb *db, robj *key, robj *val, time_t expire) { iojob *j; j = zmalloc(sizeof(*j)); @@ -543,6 +613,7 @@ void dsCreateIOJob(int type, redisDb *db, robj *key, robj *val) { incrRefCount(key); j->val = val; if (val) incrRefCount(val); + j->expire = expire; lockThreadedIO(); queueIOJob(j); @@ -596,6 +667,11 @@ void cacheScheduleIOAddFlag(redisDb *db, robj *key, long flag) { return; } else { long flags = (long) dictGetEntryVal(de); + + if (flags & flag) { + redisLog(REDIS_WARNING,"Adding the same flag again: was: %ld, addede: %ld",flags,flag); + redisAssert(!(flags & flag)); + } flags |= flag; dictGetEntryVal(de) = (void*) flags; } @@ -642,6 +718,7 @@ void cacheScheduleIO(redisDb *db, robj *key, int type) { * in queue for the same key. */ if (type == REDIS_IO_LOAD && !(flags & REDIS_IO_SAVE)) { listAddNodeHead(server.cache_io_queue, op); + cacheScheduleIOPushJobs(REDIS_IO_ONLYLOADS); } else { /* FIXME: probably when this happens we want to at least move * the write job about this queue on top, and set the creation time @@ -650,71 +727,119 @@ void cacheScheduleIO(redisDb *db, robj *key, int type) { } } -void cacheCron(void) { +/* Push scheduled IO operations into IO Jobs that the IO thread can process. + * + * If flags include REDIS_IO_ONLYLOADS only load jobs are processed:this is + * useful since it's safe to push LOAD IO jobs from any place of the code, while + * SAVE io jobs should never be pushed while we are processing a command + * (not protected by lookupKey() that will block on keys in IO_SAVEINPROG + * state. + * + * The REDIS_IO_ASAP flag tells the function to don't wait for the IO job + * scheduled completion time, but just do the operation ASAP. This is useful + * when we need to reclaim memory from the IO queue. + */ +#define MAX_IO_JOBS_QUEUE 10 +int cacheScheduleIOPushJobs(int flags) { time_t now = time(NULL); listNode *ln; - int jobs, topush = 0; + int jobs, topush = 0, pushed = 0; + + /* Don't push new jobs if there is a threaded BGSAVE in progress. */ + if (server.bgsavethread != (pthread_t) -1) return 0; - /* Sync stuff on disk, but only if we have less than 100 IO jobs */ + /* Sync stuff on disk, but only if we have less + * than MAX_IO_JOBS_QUEUE IO jobs. */ lockThreadedIO(); jobs = listLength(server.io_newjobs); unlockThreadedIO(); - topush = 100-jobs; + topush = MAX_IO_JOBS_QUEUE-jobs; if (topush < 0) topush = 0; + if (topush > (signed)listLength(server.cache_io_queue)) + topush = listLength(server.cache_io_queue); while((ln = listFirst(server.cache_io_queue)) != NULL) { ioop *op = ln->value; + struct dictEntry *de; + robj *val; if (!topush) break; topush--; - if (op->type == REDIS_IO_LOAD || - (now - op->ctime) >= server.cache_flush_delay) - { - struct dictEntry *de; - robj *val; + if (op->type != REDIS_IO_LOAD && flags & REDIS_IO_ONLYLOADS) break; - redisLog(REDIS_DEBUG,"Creating IO %s Job for key %s", - op->type == REDIS_IO_LOAD ? "load" : "save", op->key->ptr); + /* Don't execute SAVE before the scheduled time for completion */ + if (op->type == REDIS_IO_SAVE && !(flags & REDIS_IO_ASAP) && + (now - op->ctime) < server.cache_flush_delay) break; - if (op->type == REDIS_IO_LOAD) { - dsCreateIOJob(REDIS_IOJOB_LOAD,op->db,op->key,NULL); + /* Don't add a SAVE job in the IO thread queue if there is already + * a save in progress for the same key. */ + if (op->type == REDIS_IO_SAVE && + cacheScheduleIOGetFlags(op->db,op->key) & REDIS_IO_SAVEINPROG) + { + /* Move the operation at the end of the list if there + * are other operations, so we can try to process the next one. + * Otherwise break, nothing to do here. */ + if (listLength(server.cache_io_queue) > 1) { + listDelNode(server.cache_io_queue,ln); + listAddNodeTail(server.cache_io_queue,op); + continue; } else { - /* Lookup the key, in order to put the current value in the IO - * Job. Otherwise if the key does not exists we schedule a disk - * store delete operation, setting the value to NULL. */ - de = dictFind(op->db->dict,op->key->ptr); - if (de) { - val = dictGetEntryVal(de); - } else { - /* Setting the value to NULL tells the IO thread to delete - * the key on disk. */ - val = NULL; - } - dsCreateIOJob(REDIS_IOJOB_SAVE,op->db,op->key,val); + break; } - /* Mark the operation as in progress. */ - cacheScheduleIODelFlag(op->db,op->key,op->type); - cacheScheduleIOAddFlag(op->db,op->key, - (op->type == REDIS_IO_LOAD) ? REDIS_IO_LOADINPROG : - REDIS_IO_SAVEINPROG); - /* Finally remove the operation from the queue. - * But we'll have trace of it in the hash table. */ - listDelNode(server.cache_io_queue,ln); - decrRefCount(op->key); - zfree(op); + } + + redisLog(REDIS_DEBUG,"Creating IO %s Job for key %s", + op->type == REDIS_IO_LOAD ? "load" : "save", op->key->ptr); + + if (op->type == REDIS_IO_LOAD) { + cacheCreateIOJob(REDIS_IOJOB_LOAD,op->db,op->key,NULL,0); } else { - break; /* too early */ + time_t expire = -1; + + /* Lookup the key, in order to put the current value in the IO + * Job. Otherwise if the key does not exists we schedule a disk + * store delete operation, setting the value to NULL. */ + de = dictFind(op->db->dict,op->key->ptr); + if (de) { + val = dictGetEntryVal(de); + expire = getExpire(op->db,op->key); + } else { + /* Setting the value to NULL tells the IO thread to delete + * the key on disk. */ + val = NULL; + } + cacheCreateIOJob(REDIS_IOJOB_SAVE,op->db,op->key,val,expire); } + /* Mark the operation as in progress. */ + cacheScheduleIODelFlag(op->db,op->key,op->type); + cacheScheduleIOAddFlag(op->db,op->key, + (op->type == REDIS_IO_LOAD) ? REDIS_IO_LOADINPROG : + REDIS_IO_SAVEINPROG); + /* Finally remove the operation from the queue. + * But we'll have trace of it in the hash table. */ + listDelNode(server.cache_io_queue,ln); + decrRefCount(op->key); + zfree(op); + pushed++; } + return pushed; +} + +void cacheCron(void) { + /* Push jobs */ + cacheScheduleIOPushJobs(0); /* Reclaim memory from the object cache */ while (server.ds_enabled && zmalloc_used_memory() > server.cache_max_memory) { - if (cacheFreeOneEntry() == REDIS_ERR) break; - /* FIXME: also free negative cache entries here. */ + int done = 0; + + if (cacheFreeOneEntry() == REDIS_OK) done++; + if (negativeCacheEvictOneEntry() == REDIS_OK) done++; + if (done == 0) break; /* nothing more to free */ } } @@ -765,62 +890,17 @@ int waitForSwappedKey(redisClient *c, robj *key) { listAddNodeTail(l,c); /* Are we already loading the key from disk? If not create a job */ - if (de == NULL) - cacheScheduleIO(c->db,key,REDIS_IO_LOAD); - return 1; -} - -/* Preload keys for any command with first, last and step values for - * the command keys prototype, as defined in the command table. */ -void waitForMultipleSwappedKeys(redisClient *c, struct redisCommand *cmd, int argc, robj **argv) { - int j, last; - if (cmd->vm_firstkey == 0) return; - last = cmd->vm_lastkey; - if (last < 0) last = argc+last; - for (j = cmd->vm_firstkey; j <= last; j += cmd->vm_keystep) { - redisAssert(j < argc); - waitForSwappedKey(c,argv[j]); - } -} - -/* Preload keys needed for the ZUNIONSTORE and ZINTERSTORE commands. - * Note that the number of keys to preload is user-defined, so we need to - * apply a sanity check against argc. */ -void zunionInterBlockClientOnSwappedKeys(redisClient *c, struct redisCommand *cmd, int argc, robj **argv) { - int i, num; - REDIS_NOTUSED(cmd); - - num = atoi(argv[2]->ptr); - if (num > (argc-3)) return; - for (i = 0; i < num; i++) { - waitForSwappedKey(c,argv[3+i]); - } -} - -/* Preload keys needed to execute the entire MULTI/EXEC block. - * - * This function is called by blockClientOnSwappedKeys when EXEC is issued, - * and will block the client when any command requires a swapped out value. */ -void execBlockClientOnSwappedKeys(redisClient *c, struct redisCommand *cmd, int argc, robj **argv) { - int i, margc; - struct redisCommand *mcmd; - robj **margv; - REDIS_NOTUSED(cmd); - REDIS_NOTUSED(argc); - REDIS_NOTUSED(argv); - - if (!(c->flags & REDIS_MULTI)) return; - for (i = 0; i < c->mstate.count; i++) { - mcmd = c->mstate.commands[i].cmd; - margc = c->mstate.commands[i].argc; - margv = c->mstate.commands[i].argv; - - if (mcmd->vm_preload_proc != NULL) { - mcmd->vm_preload_proc(c,mcmd,margc,margv); - } else { - waitForMultipleSwappedKeys(c,mcmd,margc,margv); - } + if (de == NULL) { + int flags = cacheScheduleIOGetFlags(c->db,key); + + /* It is possible that even if there are no clients waiting for + * a load operation, still we have a load operation in progress. + * For instance think to a client performing a GET and then + * closing the connection */ + if ((flags & (REDIS_IO_LOAD|REDIS_IO_LOADINPROG)) == 0) + cacheScheduleIO(c->db,key,REDIS_IO_LOAD); } + return 1; } /* Is this client attempting to run a command against swapped keys? @@ -834,10 +914,39 @@ void execBlockClientOnSwappedKeys(redisClient *c, struct redisCommand *cmd, int * Return 1 if the client is marked as blocked, 0 if the client can * continue as the keys it is going to access appear to be in memory. */ int blockClientOnSwappedKeys(redisClient *c, struct redisCommand *cmd) { - if (cmd->vm_preload_proc != NULL) { - cmd->vm_preload_proc(c,cmd,c->argc,c->argv); + int *keyindex, numkeys, j, i; + + /* EXEC is a special case, we need to preload all the commands + * queued into the transaction */ + if (cmd->proc == execCommand) { + struct redisCommand *mcmd; + robj **margv; + int margc; + + if (!(c->flags & REDIS_MULTI)) return 0; + for (i = 0; i < c->mstate.count; i++) { + mcmd = c->mstate.commands[i].cmd; + margc = c->mstate.commands[i].argc; + margv = c->mstate.commands[i].argv; + + keyindex = getKeysFromCommand(mcmd,margv,margc,&numkeys, + REDIS_GETKEYS_PRELOAD); + for (j = 0; j < numkeys; j++) { + redisLog(REDIS_DEBUG,"Preloading %s", + (char*)margv[keyindex[j]]->ptr); + waitForSwappedKey(c,margv[keyindex[j]]); + } + getKeysFreeResult(keyindex); + } } else { - waitForMultipleSwappedKeys(c,cmd,c->argc,c->argv); + keyindex = getKeysFromCommand(cmd,c->argv,c->argc,&numkeys, + REDIS_GETKEYS_PRELOAD); + for (j = 0; j < numkeys; j++) { + redisLog(REDIS_DEBUG,"Preloading %s", + (char*)c->argv[keyindex[j]]->ptr); + waitForSwappedKey(c,c->argv[keyindex[j]]); + } + getKeysFreeResult(keyindex); } /* If the client was blocked for at least one key, mark it as blocked. */