*/
void spawnIOThread(void);
+int cacheScheduleIOPushJobs(int flags);
+int processActiveIOJobs(int max);
/* =================== Virtual Memory - Blocking Side ====================== */
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."
* 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;
}
}
if (best == NULL) {
- /* FIXME: If there are objects that are in the write queue
- * so we can't delete them we should block here, at the cost of
- * slowness as the object cache memory limit is considered
- * n hard limit. */
+ /* Was not able to fix 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);
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;
lockThreadedIO();
if (listLength(server.io_newjobs) == 0 &&
listLength(server.io_processing) == 0)
{
+ /* There is nothing more to process */
unlockThreadedIO();
- return;
+ break;
}
+
+#if 0
/* If there are new jobs we need to signal the thread to
- * process the next one. */
+ * process the next one. FIXME: drop this if useless. */
redisLog(REDIS_DEBUG,"waitEmptyIOJobsQueue: new %d, processing %d",
listLength(server.io_newjobs),
listLength(server.io_processing));
- /* FIXME: signal or not?
if (listLength(server.io_newjobs)) {
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);
unlockThreadedIO();
if (io_processed_len) {
vmThreadedIOCompletedJob(NULL,server.io_ready_pipe_read,
(void*)0xdeadbeef,0);
- /* FIXME: probably wiser to drop this sleeps. Anyway
- * the contention on the IO thread will avoid we to loop
- * too fast here. */
- usleep(1000); /* 1 millisecond */
- } else {
- /* FIXME: same as fixme above. */
- 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 */
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) {
iojob *j;
j = zmalloc(sizeof(*j));
#define REDIS_IO_LOADINPROG 4
#define REDIS_IO_SAVEINPROG 8
-void cacheScheduleIOPushJobs(int onlyloads);
-
void cacheScheduleIOAddFlag(redisDb *db, robj *key, long flag) {
struct dictEntry *de = dictFind(db->io_queued,key);
* in queue for the same key. */
if (type == REDIS_IO_LOAD && !(flags & REDIS_IO_SAVE)) {
listAddNodeHead(server.cache_io_queue, op);
- cacheScheduleIOPushJobs(1);
+ 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
}
/* Push scheduled IO operations into IO Jobs that the IO thread can process.
- * If 'onlyloads' is true only IO_LOAD jobs are processed: this is useful
- * since it's save to push LOAD IO jobs from any place of the code, while
+ *
+ * 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. */
+ * 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 100
-void cacheScheduleIOPushJobs(int onlyloads) {
+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 MAX_IO_JOBS_QUEUE IO jobs. */
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 ||
- (!onlyloads && (now - op->ctime) >= server.cache_flush_delay))
+ if (op->type != REDIS_IO_LOAD && flags & REDIS_IO_ONLYLOADS) break;
+
+ /* 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;
+
+ /* 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)
{
- struct dictEntry *de;
- robj *val;
-
- /* Don't add a SAVE job in 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 of there
- * are other operations. 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 {
- break;
- }
+ /* 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 {
+ break;
}
+ }
- redisLog(REDIS_DEBUG,"Creating IO %s Job for key %s",
- op->type == REDIS_IO_LOAD ? "load" : "save", op->key->ptr);
+ 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) {
- dsCreateIOJob(REDIS_IOJOB_LOAD,op->db,op->key,NULL);
+ if (op->type == REDIS_IO_LOAD) {
+ cacheCreateIOJob(REDIS_IOJOB_LOAD,op->db,op->key,NULL);
+ } 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 {
- /* 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);
+ /* Setting the value to NULL tells the IO thread to delete
+ * the key on disk. */
+ val = NULL;
}
- /* 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);
- } else {
- break; /* too early */
+ cacheCreateIOJob(REDIS_IOJOB_SAVE,op->db,op->key,val);
}
+ /* 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) {
projects / redis.git / blobdiff