#define REDIS_SET 2
#define REDIS_ZSET 3
#define REDIS_HASH 4
+#define REDIS_VMPOINTER 8
/* Objects encoding. Some kind of objects like Strings and Hashes can be
* internally represented in multiple ways. The 'encoding' field of the object
/* A redis object, that is a type able to hold a string / list / set */
-/* The VM object structure */
-struct redisObjectVM {
- off_t page; /* the page at witch the object is stored on disk */
- off_t usedpages; /* number of pages used on disk */
- time_t atime; /* Last access time */
-} vm;
-
/* The actual Redis Object */
typedef struct redisObject {
- void *ptr;
- unsigned char type;
- unsigned char encoding;
- unsigned char storage; /* If this object is a key, where is the value?
- * REDIS_VM_MEMORY, REDIS_VM_SWAPPED, ... */
- unsigned char vtype; /* If this object is a key, and value is swapped out,
- * this is the type of the swapped out object. */
+ unsigned type:4;
+ unsigned storage:2; /* REDIS_VM_MEMORY or REDIS_VM_SWAPPING */
+ unsigned encoding:4;
+ unsigned lru:22; /* lru time (relative to server.lruclock) */
int refcount;
+ void *ptr;
/* VM fields, this are only allocated if VM is active, otherwise the
* object allocation function will just allocate
* sizeof(redisObjct) minus sizeof(redisObjectVM), so using
* Redis without VM active will not have any overhead. */
- struct redisObjectVM vm;
} robj;
+/* The VM pointer structure - identifies an object in the swap file.
+ *
+ * This object is stored in place of the value
+ * object in the main key->value hash table representing a database.
+ * Note that the first fields (type, storage) are the same as the redisObject
+ * structure so that vmPointer strucuters can be accessed even when casted
+ * as redisObject structures.
+ *
+ * This is useful as we don't know if a value object is or not on disk, but we
+ * are always able to read obj->storage to check this. For vmPointer
+ * structures "type" is set to REDIS_VMPOINTER (even if without this field
+ * is still possible to check the kind of object from the value of 'storage').*/
+typedef struct vmPointer {
+ unsigned type:4;
+ unsigned storage:2; /* REDIS_VM_SWAPPED or REDIS_VM_LOADING */
+ unsigned notused:26;
+ unsigned int vtype; /* type of the object stored in the swap file */
+ off_t page; /* the page at witch the object is stored on disk */
+ off_t usedpages; /* number of pages used on disk */
+} vmpointer;
+
/* Macro used to initalize a Redis object allocated on the stack.
* Note that this macro is taken near the structure definition to make sure
* we'll update it when the structure is changed, to avoid bugs like
_var.type = REDIS_STRING; \
_var.encoding = REDIS_ENCODING_RAW; \
_var.ptr = _ptr; \
- if (server.vm_enabled) _var.storage = REDIS_VM_MEMORY; \
+ _var.storage = REDIS_VM_MEMORY; \
} while(0);
typedef struct redisDb {
list *pubsub_patterns; /* A list of pubsub_patterns */
/* Misc */
FILE *devnull;
+ unsigned lruclock:22; /* clock incrementing every minute, for LRU */
+ unsigned lruclock_padding:10;
};
typedef struct pubsubPattern {
int type; /* Request type, REDIS_IOJOB_* */
redisDb *db;/* Redis database */
robj *key; /* This I/O request is about swapping this key */
+ robj *id; /* Unique identifier of this job:
+ this is the object to swap for REDIS_IOREQ_*_SWAP, or the
+ vmpointer objct for REDIS_IOREQ_LOAD. */
robj *val; /* the value to swap for REDIS_IOREQ_*_SWAP, otherwise this
* field is populated by the I/O thread for REDIS_IOREQ_LOAD. */
off_t page; /* Swap page where to read/write the object */
static int handleClientsWaitingListPush(redisClient *c, robj *key, robj *ele);
static void vmInit(void);
static void vmMarkPagesFree(off_t page, off_t count);
-static robj *vmLoadObject(robj *key);
-static robj *vmPreviewObject(robj *key);
+static robj *vmLoadObject(robj *o);
+static robj *vmPreviewObject(robj *o);
static int vmSwapOneObjectBlocking(void);
static int vmSwapOneObjectThreaded(void);
static int vmCanSwapOut(void);
static int equalStringObjects(robj *a, robj *b);
static void usage();
static int rewriteAppendOnlyFileBackground(void);
-static int vmSwapObjectBlocking(robj *key, robj *val);
+static vmpointer *vmSwapObjectBlocking(robj *val);
static int prepareForShutdown();
static void touchWatchedKey(redisDb *db, robj *key);
static void touchWatchedKeysOnFlush(int dbid);
* in objects at every object access, and accuracy is not needed.
* To access a global var is faster than calling time(NULL) */
server.unixtime = time(NULL);
+ /* We have just 21 bits per object for LRU information.
+ * So we use an (eventually wrapping) LRU clock with minutes resolution.
+ *
+ * When we need to select what object to swap, we compute the minimum
+ * time distance between the current lruclock and the object last access
+ * lruclock info. Even if clocks will wrap on overflow, there is
+ * the interesting property that we are sure that at least
+ * ABS(A-B) minutes passed between current time and timestamp B.
+ *
+ * This is not precise but we don't need at all precision, but just
+ * something statistically reasonable.
+ */
+ server.lruclock = (time(NULL)/60)&((1<<21)-1);
/* We received a SIGTERM, shutting down here in a safe way, as it is
* not ok doing so inside the signal handler. */
listDelNode(server.objfreelist,head);
if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
} else {
- if (server.vm_enabled) {
+ if (server.vm_enabled)
pthread_mutex_unlock(&server.obj_freelist_mutex);
- o = zmalloc(sizeof(*o));
- } else {
- o = zmalloc(sizeof(*o)-sizeof(struct redisObjectVM));
- }
+ o = zmalloc(sizeof(*o));
}
o->type = type;
o->encoding = REDIS_ENCODING_RAW;
o->refcount = 1;
if (server.vm_enabled) {
/* Note that this code may run in the context of an I/O thread
- * and accessing to server.unixtime in theory is an error
+ * and accessing server.lruclock in theory is an error
* (no locks). But in practice this is safe, and even if we read
- * garbage Redis will not fail, as it's just a statistical info */
- o->vm.atime = server.unixtime;
+ * garbage Redis will not fail. */
+ o->lru = server.lruclock;
o->storage = REDIS_VM_MEMORY;
}
return o;
static void decrRefCount(void *obj) {
robj *o = obj;
- if (o->refcount <= 0) redisPanic("decrRefCount against refcount <= 0");
- /* Object is a key of a swapped out value, or in the process of being
- * loaded. */
+ /* Object is a swapped out value, or in the process of being loaded. */
if (server.vm_enabled &&
(o->storage == REDIS_VM_SWAPPED || o->storage == REDIS_VM_LOADING))
{
- if (o->storage == REDIS_VM_LOADING) vmCancelThreadedIOJob(obj);
- redisAssert(o->type == REDIS_STRING);
- freeStringObject(o);
- vmMarkPagesFree(o->vm.page,o->vm.usedpages);
- pthread_mutex_lock(&server.obj_freelist_mutex);
- if (listLength(server.objfreelist) > REDIS_OBJFREELIST_MAX ||
- !listAddNodeHead(server.objfreelist,o))
- zfree(o);
- pthread_mutex_unlock(&server.obj_freelist_mutex);
+ vmpointer *vp = obj;
+ if (o->storage == REDIS_VM_LOADING) vmCancelThreadedIOJob(o);
+ vmMarkPagesFree(vp->page,vp->usedpages);
server.vm_stats_swapped_objects--;
+ zfree(vp);
return;
}
- /* Object is in memory, or in the process of being swapped out. */
+
+ if (o->refcount <= 0) redisPanic("decrRefCount against refcount <= 0");
+ /* Object is in memory, or in the process of being swapped out.
+ *
+ * If the object is being swapped out, abort the operation on
+ * decrRefCount even if the refcount does not drop to 0: the object
+ * is referenced at least two times, as value of the key AND as
+ * job->val in the iojob. So if we don't invalidate the iojob, when it is
+ * done but the relevant key was removed in the meantime, the
+ * complete jobs handler will not find the key about the job and the
+ * assert will fail. */
+ if (server.vm_enabled && o->storage == REDIS_VM_SWAPPING)
+ vmCancelThreadedIOJob(o);
if (--(o->refcount) == 0) {
- if (server.vm_enabled && o->storage == REDIS_VM_SWAPPING)
- vmCancelThreadedIOJob(obj);
switch(o->type) {
case REDIS_STRING: freeStringObject(o); break;
case REDIS_LIST: freeListObject(o); break;
}
}
-static robj *lookupKey(redisDb *db, robj *key) {
- dictEntry *de = dictFind(db->dict,key);
- if (de) {
- robj *key = dictGetEntryKey(de);
- robj *val = dictGetEntryVal(de);
-
- if (server.vm_enabled) {
- if (key->storage == REDIS_VM_MEMORY ||
- key->storage == REDIS_VM_SWAPPING)
- {
- /* If we were swapping the object out, stop it, this key
- * was requested. */
- if (key->storage == REDIS_VM_SWAPPING)
- vmCancelThreadedIOJob(key);
- /* Update the access time of the key for the aging algorithm. */
- key->vm.atime = server.unixtime;
- } else {
- int notify = (key->storage == REDIS_VM_LOADING);
-
- /* Our value was swapped on disk. Bring it at home. */
- redisAssert(val == NULL);
- val = vmLoadObject(key);
- dictGetEntryVal(de) = val;
-
- /* Clients blocked by the VM subsystem may be waiting for
- * this key... */
- if (notify) handleClientsBlockedOnSwappedKey(db,key);
- }
- }
- return val;
- } else {
- return NULL;
- }
-}
-
-static robj *lookupKeyRead(redisDb *db, robj *key) {
- expireIfNeeded(db,key);
- return lookupKey(db,key);
-}
-
-static robj *lookupKeyWrite(redisDb *db, robj *key) {
- deleteIfVolatile(db,key);
- touchWatchedKey(db,key);
- return lookupKey(db,key);
-}
-
-static robj *lookupKeyReadOrReply(redisClient *c, robj *key, robj *reply) {
- robj *o = lookupKeyRead(c->db, key);
- if (!o) addReply(c,reply);
- return o;
-}
-
-static robj *lookupKeyWriteOrReply(redisClient *c, robj *key, robj *reply) {
- robj *o = lookupKeyWrite(c->db, key);
- if (!o) addReply(c,reply);
- return o;
-}
-
static int checkType(redisClient *c, robj *o, int type) {
if (o->type != type) {
addReply(c,shared.wrongtypeerr);
return 0;
}
-static int deleteKey(redisDb *db, robj *key) {
- int retval;
-
- /* We need to protect key from destruction: after the first dictDelete()
- * it may happen that 'key' is no longer valid if we don't increment
- * it's count. This may happen when we get the object reference directly
- * from the hash table with dictRandomKey() or dict iterators */
- incrRefCount(key);
- if (dictSize(db->expires)) dictDelete(db->expires,key);
- retval = dictDelete(db->dict,key);
- decrRefCount(key);
-
- return retval == DICT_OK;
-}
-
/* Check if the nul-terminated string 's' can be represented by a long
* (that is, is a number that fits into long without any other space or
* character before or after the digits).
return REDIS_OK;
}
+/* =========================== Keyspace access API ========================== */
+
+static robj *lookupKey(redisDb *db, robj *key) {
+ dictEntry *de = dictFind(db->dict,key);
+ if (de) {
+ robj *key = dictGetEntryKey(de);
+ robj *val = dictGetEntryVal(de);
+
+ if (server.vm_enabled) {
+ if (val->storage == REDIS_VM_MEMORY ||
+ val->storage == REDIS_VM_SWAPPING)
+ {
+ /* If we were swapping the object out, cancel the operation */
+ if (val->storage == REDIS_VM_SWAPPING)
+ vmCancelThreadedIOJob(val);
+ /* Update the access time of the key for the aging algorithm. */
+ val->lru = server.lruclock;
+ } else {
+ int notify = (val->storage == REDIS_VM_LOADING);
+
+ /* Our value was swapped on disk. Bring it at home. */
+ redisAssert(val->type == REDIS_VMPOINTER);
+ val = vmLoadObject(val);
+ dictGetEntryVal(de) = val;
+
+ /* Clients blocked by the VM subsystem may be waiting for
+ * this key... */
+ if (notify) handleClientsBlockedOnSwappedKey(db,key);
+ }
+ }
+ return val;
+ } else {
+ return NULL;
+ }
+}
+
+static robj *lookupKeyRead(redisDb *db, robj *key) {
+ expireIfNeeded(db,key);
+ return lookupKey(db,key);
+}
+
+static robj *lookupKeyWrite(redisDb *db, robj *key) {
+ deleteIfVolatile(db,key);
+ touchWatchedKey(db,key);
+ return lookupKey(db,key);
+}
+
+static robj *lookupKeyReadOrReply(redisClient *c, robj *key, robj *reply) {
+ robj *o = lookupKeyRead(c->db, key);
+ if (!o) addReply(c,reply);
+ return o;
+}
+
+static robj *lookupKeyWriteOrReply(redisClient *c, robj *key, robj *reply) {
+ robj *o = lookupKeyWrite(c->db, key);
+ if (!o) addReply(c,reply);
+ return o;
+}
+
+static int deleteKey(redisDb *db, robj *key) {
+ int retval;
+
+ /* We need to protect key from destruction: after the first dictDelete()
+ * it may happen that 'key' is no longer valid if we don't increment
+ * it's count. This may happen when we get the object reference directly
+ * from the hash table with dictRandomKey() or dict iterators */
+ incrRefCount(key);
+ if (dictSize(db->expires)) dictDelete(db->expires,key);
+ retval = dictDelete(db->dict,key);
+ decrRefCount(key);
+
+ return retval == DICT_OK;
+}
+
/*============================ RDB saving/loading =========================== */
static int rdbSaveType(FILE *fp, unsigned char type) {
}
/* Save the key and associated value. This requires special
* handling if the value is swapped out. */
- if (!server.vm_enabled || key->storage == REDIS_VM_MEMORY ||
- key->storage == REDIS_VM_SWAPPING) {
+ if (!server.vm_enabled || o->storage == REDIS_VM_MEMORY ||
+ o->storage == REDIS_VM_SWAPPING) {
/* Save type, key, value */
if (rdbSaveType(fp,o->type) == -1) goto werr;
if (rdbSaveStringObject(fp,key) == -1) goto werr;
/* REDIS_VM_SWAPPED or REDIS_VM_LOADING */
robj *po;
/* Get a preview of the object in memory */
- po = vmPreviewObject(key);
+ po = vmPreviewObject(o);
/* Save type, key, value */
- if (rdbSaveType(fp,key->vtype) == -1) goto werr;
+ if (rdbSaveType(fp,po->type) == -1) goto werr;
if (rdbSaveStringObject(fp,key) == -1) goto werr;
if (rdbSaveObject(fp,po) == -1) goto werr;
/* Remove the loaded object from memory */
/* de may be NULL since the key already expired */
if (de) {
+ vmpointer *vp;
key = dictGetEntryKey(de);
val = dictGetEntryVal(de);
- if (vmSwapObjectBlocking(key,val) == REDIS_OK) {
- dictGetEntryVal(de) = NULL;
- }
+ if (val->refcount == 1 &&
+ (vp = vmSwapObjectBlocking(val)) != NULL)
+ dictGetEntryVal(de) = vp;
}
continue;
}
/* ============================== Append Only file ========================== */
+/* Called when the user switches from "appendonly yes" to "appendonly no"
+ * at runtime using the CONFIG command. */
+static void stopAppendOnly(void) {
+ flushAppendOnlyFile();
+ aof_fsync(server.appendfd);
+ close(server.appendfd);
+
+ server.appendfd = -1;
+ server.appendseldb = -1;
+ server.appendonly = 0;
+ /* rewrite operation in progress? kill it, wait child exit */
+ if (server.bgsavechildpid != -1) {
+ int statloc;
+
+ if (kill(server.bgsavechildpid,SIGKILL) != -1)
+ wait3(&statloc,0,NULL);
+ /* reset the buffer accumulating changes while the child saves */
+ sdsfree(server.bgrewritebuf);
+ server.bgrewritebuf = sdsempty();
+ server.bgsavechildpid = -1;
+ }
+}
+
+/* Called when the user switches from "appendonly no" to "appendonly yes"
+ * at runtime using the CONFIG command. */
+static int startAppendOnly(void) {
+ server.appendonly = 1;
+ server.lastfsync = time(NULL);
+ server.appendfd = open(server.appendfilename,O_WRONLY|O_APPEND|O_CREAT,0644);
+ if (server.appendfd == -1) {
+ redisLog(REDIS_WARNING,"Used tried to switch on AOF via CONFIG, but I can't open the AOF file: %s",strerror(errno));
+ return REDIS_ERR;
+ }
+ if (rewriteAppendOnlyFileBackground() == REDIS_ERR) {
+ server.appendonly = 0;
+ close(server.appendfd);
+ redisLog(REDIS_WARNING,"Used tried to switch on AOF via CONFIG, I can't trigger a background AOF rewrite operation. Check the above logs for more info about the error.",strerror(errno));
+ return REDIS_ERR;
+ }
+ return REDIS_OK;
+}
+
/* Write the append only file buffer on disk.
*
* Since we are required to write the AOF before replying to the client,
int swapped;
key = dictGetEntryKey(de);
+ o = dictGetEntryVal(de);
/* If the value for this key is swapped, load a preview in memory.
* We use a "swapped" flag to remember if we need to free the
* value object instead to just increment the ref count anyway
* in order to avoid copy-on-write of pages if we are forked() */
- if (!server.vm_enabled || key->storage == REDIS_VM_MEMORY ||
- key->storage == REDIS_VM_SWAPPING) {
- o = dictGetEntryVal(de);
+ if (!server.vm_enabled || o->storage == REDIS_VM_MEMORY ||
+ o->storage == REDIS_VM_SWAPPING) {
swapped = 0;
} else {
- o = vmPreviewObject(key);
+ o = vmPreviewObject(o);
swapped = 1;
}
expiretime = getExpire(db,key);
* as a fully non-blocking VM.
*/
-/* Called when the user switches from "appendonly yes" to "appendonly no"
- * at runtime using the CONFIG command. */
-static void stopAppendOnly(void) {
- flushAppendOnlyFile();
- aof_fsync(server.appendfd);
- close(server.appendfd);
-
- server.appendfd = -1;
- server.appendseldb = -1;
- server.appendonly = 0;
- /* rewrite operation in progress? kill it, wait child exit */
- if (server.bgsavechildpid != -1) {
- int statloc;
+/* =================== Virtual Memory - Blocking Side ====================== */
- if (kill(server.bgsavechildpid,SIGKILL) != -1)
- wait3(&statloc,0,NULL);
- /* reset the buffer accumulating changes while the child saves */
- sdsfree(server.bgrewritebuf);
- server.bgrewritebuf = sdsempty();
- server.bgsavechildpid = -1;
- }
-}
+/* Create a VM pointer object. This kind of objects are used in place of
+ * values in the key -> value hash table, for swapped out objects. */
+static vmpointer *createVmPointer(int vtype) {
+ vmpointer *vp = zmalloc(sizeof(vmpointer));
-/* Called when the user switches from "appendonly no" to "appendonly yes"
- * at runtime using the CONFIG command. */
-static int startAppendOnly(void) {
- server.appendonly = 1;
- server.lastfsync = time(NULL);
- server.appendfd = open(server.appendfilename,O_WRONLY|O_APPEND|O_CREAT,0644);
- if (server.appendfd == -1) {
- redisLog(REDIS_WARNING,"Used tried to switch on AOF via CONFIG, but I can't open the AOF file: %s",strerror(errno));
- return REDIS_ERR;
- }
- if (rewriteAppendOnlyFileBackground() == REDIS_ERR) {
- server.appendonly = 0;
- close(server.appendfd);
- redisLog(REDIS_WARNING,"Used tried to switch on AOF via CONFIG, I can't trigger a background AOF rewrite operation. Check the above logs for more info about the error.",strerror(errno));
- return REDIS_ERR;
- }
- return REDIS_OK;
+ vp->type = REDIS_VMPOINTER;
+ vp->storage = REDIS_VM_SWAPPED;
+ vp->vtype = vtype;
+ return vp;
}
-/* =================== Virtual Memory - Blocking Side ====================== */
-
static void vmInit(void) {
off_t totsize;
int pipefds[2];
return REDIS_OK;
}
-/* Swap the 'val' object relative to 'key' into disk. Store all the information
- * needed to later retrieve the object into the key object.
+/* Transfers the 'val' object to disk. Store all the information
+ * a 'vmpointer' object containing all the information needed to load the
+ * object back later is returned.
+ *
* If we can't find enough contiguous empty pages to swap the object on disk
- * REDIS_ERR is returned. */
-static int vmSwapObjectBlocking(robj *key, robj *val) {
+ * NULL is returned. */
+static vmpointer *vmSwapObjectBlocking(robj *val) {
off_t pages = rdbSavedObjectPages(val,NULL);
off_t page;
+ vmpointer *vp;
- assert(key->storage == REDIS_VM_MEMORY);
- assert(key->refcount == 1);
- if (vmFindContiguousPages(&page,pages) == REDIS_ERR) return REDIS_ERR;
- if (vmWriteObjectOnSwap(val,page) == REDIS_ERR) return REDIS_ERR;
- key->vm.page = page;
- key->vm.usedpages = pages;
- key->storage = REDIS_VM_SWAPPED;
- key->vtype = val->type;
+ assert(val->storage == REDIS_VM_MEMORY);
+ assert(val->refcount == 1);
+ if (vmFindContiguousPages(&page,pages) == REDIS_ERR) return NULL;
+ if (vmWriteObjectOnSwap(val,page) == REDIS_ERR) return NULL;
+
+ vp = createVmPointer(val->type);
+ vp->page = page;
+ vp->usedpages = pages;
decrRefCount(val); /* Deallocate the object from memory. */
vmMarkPagesUsed(page,pages);
- redisLog(REDIS_DEBUG,"VM: object %s swapped out at %lld (%lld pages)",
- (unsigned char*) key->ptr,
+ redisLog(REDIS_DEBUG,"VM: object %p swapped out at %lld (%lld pages)",
+ (void*) val,
(unsigned long long) page, (unsigned long long) pages);
server.vm_stats_swapped_objects++;
server.vm_stats_swapouts++;
- return REDIS_OK;
+ return vp;
}
static robj *vmReadObjectFromSwap(off_t page, int type) {
return o;
}
-/* Load the value object relative to the 'key' object from swap to memory.
+/* Load the specified object from swap to memory.
* The newly allocated object is returned.
*
* If preview is true the unserialized object is returned to the caller but
- * no changes are made to the key object, nor the pages are marked as freed */
-static robj *vmGenericLoadObject(robj *key, int preview) {
+ * the pages are not marked as freed, nor the vp object is freed. */
+static robj *vmGenericLoadObject(vmpointer *vp, int preview) {
robj *val;
- redisAssert(key->storage == REDIS_VM_SWAPPED || key->storage == REDIS_VM_LOADING);
- val = vmReadObjectFromSwap(key->vm.page,key->vtype);
+ redisAssert(vp->type == REDIS_VMPOINTER &&
+ (vp->storage == REDIS_VM_SWAPPED || vp->storage == REDIS_VM_LOADING));
+ val = vmReadObjectFromSwap(vp->page,vp->vtype);
if (!preview) {
- key->storage = REDIS_VM_MEMORY;
- key->vm.atime = server.unixtime;
- vmMarkPagesFree(key->vm.page,key->vm.usedpages);
- redisLog(REDIS_DEBUG, "VM: object %s loaded from disk",
- (unsigned char*) key->ptr);
+ redisLog(REDIS_DEBUG, "VM: object %p loaded from disk", (void*)vp);
+ vmMarkPagesFree(vp->page,vp->usedpages);
+ zfree(vp);
server.vm_stats_swapped_objects--;
} else {
- redisLog(REDIS_DEBUG, "VM: object %s previewed from disk",
- (unsigned char*) key->ptr);
+ redisLog(REDIS_DEBUG, "VM: object %p previewed from disk", (void*)vp);
}
server.vm_stats_swapins++;
return val;
}
-/* Plain object loading, from swap to memory */
-static robj *vmLoadObject(robj *key) {
+/* Plain object loading, from swap to memory.
+ *
+ * 'o' is actually a redisVmPointer structure that will be freed by the call.
+ * The return value is the loaded object. */
+static robj *vmLoadObject(robj *o) {
/* If we are loading the object in background, stop it, we
* need to load this object synchronously ASAP. */
- if (key->storage == REDIS_VM_LOADING)
- vmCancelThreadedIOJob(key);
- return vmGenericLoadObject(key,0);
+ if (o->storage == REDIS_VM_LOADING)
+ vmCancelThreadedIOJob(o);
+ return vmGenericLoadObject((vmpointer*)o,0);
}
/* Just load the value on disk, without to modify the key.
* This is useful when we want to perform some operation on the value
* without to really bring it from swap to memory, like while saving the
* dataset or rewriting the append only log. */
-static robj *vmPreviewObject(robj *key) {
- return vmGenericLoadObject(key,1);
+static robj *vmPreviewObject(robj *o) {
+ return vmGenericLoadObject((vmpointer*)o,1);
}
/* How a good candidate is this object for swapping?
* proportionally, this is why we use the logarithm. This algorithm is
* just a first try and will probably be tuned later. */
static double computeObjectSwappability(robj *o) {
- time_t age = server.unixtime - o->vm.atime;
+ /* actual age can be >= minage, but not < minage. As we use wrapping
+ * 21 bit clocks with minutes resolution for the LRU. */
+ time_t minage = abs(server.lruclock - o->lru);
long asize = 0;
list *l;
dict *d;
struct dictEntry *de;
int z;
- if (age <= 0) return 0;
+ if (minage <= 0) return 0;
switch(o->type) {
case REDIS_STRING:
if (o->encoding != REDIS_ENCODING_RAW) {
long elesize;
elesize = (ele->encoding == REDIS_ENCODING_RAW) ?
- (sizeof(*o)+sdslen(ele->ptr)) :
- sizeof(*o);
+ (sizeof(*o)+sdslen(ele->ptr)) : sizeof(*o);
asize += (sizeof(listNode)+elesize)*listLength(l);
}
break;
de = dictGetRandomKey(d);
ele = dictGetEntryKey(de);
elesize = (ele->encoding == REDIS_ENCODING_RAW) ?
- (sizeof(*o)+sdslen(ele->ptr)) :
- sizeof(*o);
+ (sizeof(*o)+sdslen(ele->ptr)) : sizeof(*o);
asize += (sizeof(struct dictEntry)+elesize)*dictSize(d);
if (z) asize += sizeof(zskiplistNode)*dictSize(d);
}
de = dictGetRandomKey(d);
ele = dictGetEntryKey(de);
elesize = (ele->encoding == REDIS_ENCODING_RAW) ?
- (sizeof(*o)+sdslen(ele->ptr)) :
- sizeof(*o);
+ (sizeof(*o)+sdslen(ele->ptr)) : sizeof(*o);
ele = dictGetEntryVal(de);
elesize = (ele->encoding == REDIS_ENCODING_RAW) ?
- (sizeof(*o)+sdslen(ele->ptr)) :
- sizeof(*o);
+ (sizeof(*o)+sdslen(ele->ptr)) : sizeof(*o);
asize += (sizeof(struct dictEntry)+elesize)*dictSize(d);
}
}
break;
}
- return (double)age*log(1+asize);
+ return (double)minage*log(1+asize);
}
/* Try to swap an object that's a good candidate for swapping.
val = dictGetEntryVal(de);
/* Only swap objects that are currently in memory.
*
- * Also don't swap shared objects if threaded VM is on, as we
- * try to ensure that the main thread does not touch the
+ * Also don't swap shared objects: not a good idea in general and
+ * we need to ensure that the main thread does not touch the
* object while the I/O thread is using it, but we can't
* control other keys without adding additional mutex. */
- if (key->storage != REDIS_VM_MEMORY ||
- (server.vm_max_threads != 0 && val->refcount != 1)) {
+ if (val->storage != REDIS_VM_MEMORY || val->refcount != 1) {
if (maxtries) i--; /* don't count this try */
continue;
}
redisLog(REDIS_DEBUG,"Key with best swappability: %s, %f",
key->ptr, best_swappability);
- /* Unshare the key if needed */
- if (key->refcount > 1) {
- robj *newkey = dupStringObject(key);
- decrRefCount(key);
- key = dictGetEntryKey(best) = newkey;
- }
/* Swap it */
if (usethreads) {
vmSwapObjectThreaded(key,val,best_db);
return REDIS_OK;
} else {
- if (vmSwapObjectBlocking(key,val) == REDIS_OK) {
- dictGetEntryVal(best) = NULL;
+ vmpointer *vp;
+
+ if ((vp = vmSwapObjectBlocking(val)) != NULL) {
+ dictGetEntryVal(best) = vp;
return REDIS_OK;
} else {
return REDIS_ERR;
/* Delete a key if swapped. Returns 1 if the key was found, was swapped
* and was deleted. Otherwise 0 is returned. */
static int deleteIfSwapped(redisDb *db, robj *key) {
- dictEntry *de;
- robj *foundkey;
+ robj *val;
- if ((de = dictFind(db->dict,key)) == NULL) return 0;
- foundkey = dictGetEntryKey(de);
- if (foundkey->storage == REDIS_VM_MEMORY) return 0;
+ if ((val = dictFetchValue(db->dict,key)) == NULL) return 0;
+ if (val->storage == REDIS_VM_MEMORY) return 0;
deleteKey(db,key);
return 1;
}
if ((j->type == REDIS_IOJOB_PREPARE_SWAP ||
j->type == REDIS_IOJOB_DO_SWAP ||
j->type == REDIS_IOJOB_LOAD) && j->val != NULL)
+ {
+ /* we fix the storage type, otherwise decrRefCount() will try to
+ * kill the I/O thread Job (that does no longer exists). */
+ if (j->val->storage == REDIS_VM_SWAPPING)
+ j->val->storage = REDIS_VM_MEMORY;
decrRefCount(j->val);
- /* We don't decrRefCount the j->key field as we did't incremented
- * the count creating IO Jobs. This is because the key field here is
- * just used as an indentifier and if a key is removed the Job should
- * never be touched again. */
+ }
+ decrRefCount(j->key);
zfree(j);
}
while((retval = read(fd,buf,1)) == 1) {
iojob *j;
listNode *ln;
- robj *key;
struct dictEntry *de;
redisLog(REDIS_DEBUG,"Processing I/O completed job");
}
/* Post process it in the main thread, as there are things we
* can do just here to avoid race conditions and/or invasive locks */
- redisLog(REDIS_DEBUG,"Job %p type: %d, key at %p (%s) refcount: %d\n", (void*) j, j->type, (void*)j->key, (char*)j->key->ptr, j->key->refcount);
+ redisLog(REDIS_DEBUG,"COMPLETED Job type: %d, ID %p, key: %s", j->type, (void*)j->id, (unsigned char*)j->key->ptr);
de = dictFind(j->db->dict,j->key);
- assert(de != NULL);
- key = dictGetEntryKey(de);
+ redisAssert(de != NULL);
if (j->type == REDIS_IOJOB_LOAD) {
redisDb *db;
+ vmpointer *vp = dictGetEntryVal(de);
/* Key loaded, bring it at home */
- key->storage = REDIS_VM_MEMORY;
- key->vm.atime = server.unixtime;
- vmMarkPagesFree(key->vm.page,key->vm.usedpages);
+ vmMarkPagesFree(vp->page,vp->usedpages);
redisLog(REDIS_DEBUG, "VM: object %s loaded from disk (threaded)",
- (unsigned char*) key->ptr);
+ (unsigned char*) j->key->ptr);
server.vm_stats_swapped_objects--;
server.vm_stats_swapins++;
dictGetEntryVal(de) = j->val;
incrRefCount(j->val);
db = j->db;
- freeIOJob(j);
/* Handle clients waiting for this key to be loaded. */
- handleClientsBlockedOnSwappedKey(db,key);
+ handleClientsBlockedOnSwappedKey(db,j->key);
+ freeIOJob(j);
+ zfree(vp);
} else if (j->type == REDIS_IOJOB_PREPARE_SWAP) {
/* Now we know the amount of pages required to swap this object.
* Let's find some space for it, and queue this task again
{
/* Ooops... no space or we can't swap as there is
* a fork()ed Redis trying to save stuff on disk. */
+ j->val->storage = REDIS_VM_MEMORY; /* undo operation */
freeIOJob(j);
- key->storage = REDIS_VM_MEMORY; /* undo operation */
} else {
/* Note that we need to mark this pages as used now,
* if the job will be canceled, we'll mark them as freed
unlockThreadedIO();
}
} else if (j->type == REDIS_IOJOB_DO_SWAP) {
- robj *val;
+ vmpointer *vp;
/* Key swapped. We can finally free some memory. */
- if (key->storage != REDIS_VM_SWAPPING) {
- printf("key->storage: %d\n",key->storage);
- printf("key->name: %s\n",(char*)key->ptr);
- printf("key->refcount: %d\n",key->refcount);
+ if (j->val->storage != REDIS_VM_SWAPPING) {
+ vmpointer *vp = (vmpointer*) j->id;
+ printf("storage: %d\n",vp->storage);
+ printf("key->name: %s\n",(char*)j->key->ptr);
printf("val: %p\n",(void*)j->val);
printf("val->type: %d\n",j->val->type);
printf("val->ptr: %s\n",(char*)j->val->ptr);
}
- redisAssert(key->storage == REDIS_VM_SWAPPING);
- val = dictGetEntryVal(de);
- key->vm.page = j->page;
- key->vm.usedpages = j->pages;
- key->storage = REDIS_VM_SWAPPED;
- key->vtype = j->val->type;
- decrRefCount(val); /* Deallocate the object from memory. */
- dictGetEntryVal(de) = NULL;
+ redisAssert(j->val->storage == REDIS_VM_SWAPPING);
+ vp = createVmPointer(j->val->type);
+ vp->page = j->page;
+ vp->usedpages = j->pages;
+ dictGetEntryVal(de) = vp;
+ /* Fix the storage otherwise decrRefCount will attempt to
+ * remove the associated I/O job */
+ j->val->storage = REDIS_VM_MEMORY;
+ decrRefCount(j->val);
redisLog(REDIS_DEBUG,
"VM: object %s swapped out at %lld (%lld pages) (threaded)",
- (unsigned char*) key->ptr,
+ (unsigned char*) j->key->ptr,
(unsigned long long) j->page, (unsigned long long) j->pages);
server.vm_stats_swapped_objects++;
server.vm_stats_swapouts++;
assert(o->storage == REDIS_VM_LOADING || o->storage == REDIS_VM_SWAPPING);
again:
lockThreadedIO();
- /* Search for a matching key in one of the queues */
+ /* Search for a matching object in one of the queues */
for (i = 0; i < 3; i++) {
listNode *ln;
listIter li;
iojob *job = ln->value;
if (job->canceled) continue; /* Skip this, already canceled. */
- if (job->key == o) {
- redisLog(REDIS_DEBUG,"*** CANCELED %p (%s) (type %d) (LIST ID %d)\n",
- (void*)job, (char*)o->ptr, job->type, i);
+ if (job->id == o) {
+ redisLog(REDIS_DEBUG,"*** CANCELED %p (key %s) (type %d) (LIST ID %d)\n",
+ (void*)job, (char*)job->key->ptr, job->type, i);
/* Mark the pages as free since the swap didn't happened
* or happened but is now discarded. */
if (i != 1 && job->type == REDIS_IOJOB_DO_SWAP)
else if (o->storage == REDIS_VM_SWAPPING)
o->storage = REDIS_VM_MEMORY;
unlockThreadedIO();
+ redisLog(REDIS_DEBUG,"*** DONE");
return;
}
}
}
unlockThreadedIO();
- assert(1 != 1); /* We should never reach this */
+ printf("Not found: %p\n", (void*)o);
+ redisAssert(1 != 1); /* We should never reach this */
}
static void *IOThreadEntryPoint(void *arg) {
/* Process the Job */
if (j->type == REDIS_IOJOB_LOAD) {
- j->val = vmReadObjectFromSwap(j->page,j->key->vtype);
+ vmpointer *vp = (vmpointer*)j->id;
+ j->val = vmReadObjectFromSwap(j->page,vp->vtype);
} else if (j->type == REDIS_IOJOB_PREPARE_SWAP) {
FILE *fp = fopen("/dev/null","w+");
j->pages = rdbSavedObjectPages(j->val,fp);
iojob *j;
assert(key->storage == REDIS_VM_MEMORY);
- assert(key->refcount == 1);
j = zmalloc(sizeof(*j));
j->type = REDIS_IOJOB_PREPARE_SWAP;
j->db = db;
j->key = key;
- j->val = val;
+ incrRefCount(key);
+ j->id = j->val = val;
incrRefCount(val);
j->canceled = 0;
j->thread = (pthread_t) -1;
- key->storage = REDIS_VM_SWAPPING;
+ val->storage = REDIS_VM_SWAPPING;
lockThreadedIO();
queueIOJob(j);
* block the client at all. */
de = dictFind(c->db->dict,key);
if (de == NULL) return 0;
- o = dictGetEntryKey(de);
+ o = dictGetEntryVal(de);
if (o->storage == REDIS_VM_MEMORY) {
return 0;
} else if (o->storage == REDIS_VM_SWAPPING) {
/* Are we already loading the key from disk? If not create a job */
if (o->storage == REDIS_VM_SWAPPED) {
iojob *j;
+ vmpointer *vp = (vmpointer*)o;
o->storage = REDIS_VM_LOADING;
j = zmalloc(sizeof(*j));
j->type = REDIS_IOJOB_LOAD;
j->db = c->db;
- j->key = o;
- j->key->vtype = o->vtype;
- j->page = o->vm.page;
+ j->id = (robj*)vp;
+ j->key = key;
+ incrRefCount(key);
+ j->page = vp->page;
j->val = NULL;
j->canceled = 0;
j->thread = (pthread_t) -1;
return listLength(c->io_keys) == 0;
}
+/* Every time we now a key was loaded back in memory, we handle clients
+ * waiting for this key if any. */
static void handleClientsBlockedOnSwappedKey(redisDb *db, robj *key) {
struct dictEntry *de;
list *l;
}
key = dictGetEntryKey(de);
val = dictGetEntryVal(de);
- if (!server.vm_enabled || (key->storage == REDIS_VM_MEMORY ||
- key->storage == REDIS_VM_SWAPPING)) {
+ if (!server.vm_enabled || (val->storage == REDIS_VM_MEMORY ||
+ val->storage == REDIS_VM_SWAPPING)) {
char *strenc;
char buf[128];
(void*)key, key->refcount, (void*)val, val->refcount,
strenc, (long long) rdbSavedObjectLen(val,NULL)));
} else {
+ vmpointer *vp = (vmpointer*) val;
addReplySds(c,sdscatprintf(sdsempty(),
"+Key at:%p refcount:%d, value swapped at: page %llu "
"using %llu pages\r\n",
- (void*)key, key->refcount, (unsigned long long) key->vm.page,
- (unsigned long long) key->vm.usedpages));
+ (void*)key, key->refcount, (unsigned long long) vp->page,
+ (unsigned long long) vp->usedpages));
}
} else if (!strcasecmp(c->argv[1]->ptr,"swapin") && c->argc == 3) {
lookupKeyRead(c->db,c->argv[2]);
} else if (!strcasecmp(c->argv[1]->ptr,"swapout") && c->argc == 3) {
dictEntry *de = dictFind(c->db->dict,c->argv[2]);
robj *key, *val;
+ vmpointer *vp;
if (!server.vm_enabled) {
addReplySds(c,sdsnew("-ERR Virtual Memory is disabled\r\n"));
}
key = dictGetEntryKey(de);
val = dictGetEntryVal(de);
- /* If the key is shared we want to create a copy */
- if (key->refcount > 1) {
- robj *newkey = dupStringObject(key);
- decrRefCount(key);
- key = dictGetEntryKey(de) = newkey;
- }
/* Swap it */
- if (key->storage != REDIS_VM_MEMORY) {
+ if (val->storage != REDIS_VM_MEMORY) {
addReplySds(c,sdsnew("-ERR This key is not in memory\r\n"));
- } else if (vmSwapObjectBlocking(key,val) == REDIS_OK) {
- dictGetEntryVal(de) = NULL;
+ } else if (val->refcount != 1) {
+ addReplySds(c,sdsnew("-ERR Object is shared\r\n"));
+ } else if ((vp = vmSwapObjectBlocking(val)) != NULL) {
+ dictGetEntryVal(de) = vp;
addReply(c,shared.ok);
} else {
addReply(c,shared.err);
projects / redis.git / commitdiff
