#include <math.h>
robj *createObject(int type, void *ptr) {
- robj *o;
-
- if (server.vm_enabled) pthread_mutex_lock(&server.obj_freelist_mutex);
- if (listLength(server.objfreelist)) {
- listNode *head = listFirst(server.objfreelist);
- o = listNodeValue(head);
- listDelNode(server.objfreelist,head);
- if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
- } else {
- if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
- o = zmalloc(sizeof(*o));
- }
+ robj *o = zmalloc(sizeof(*o));
o->type = type;
o->encoding = REDIS_ENCODING_RAW;
o->ptr = ptr;
o->refcount = 1;
- if (server.vm_enabled) {
- /* Note that this code may run in the context of an I/O thread
- * 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. */
- o->lru = server.lruclock;
- o->storage = REDIS_VM_MEMORY;
- }
+
+ /* Set the LRU to the current lruclock (minutes resolution).
+ * We do this regardless of the fact VM is active as LRU is also
+ * used for the maxmemory directive when Redis is used as cache.
+ *
+ * Note that this code may run in the context of an I/O thread
+ * 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. */
+ o->lru = server.lruclock;
+ /* The following is only needed if VM is active, but since the conditional
+ * is probably more costly than initializing the field it's better to
+ * have every field properly initialized anyway. */
+ o->storage = REDIS_VM_MEMORY;
return o;
}
default: redisPanic("Unknown object type"); break;
}
o->ptr = NULL; /* defensive programming. We'll see NULL in traces. */
- if (server.vm_enabled) pthread_mutex_lock(&server.obj_freelist_mutex);
- if (listLength(server.objfreelist) > REDIS_OBJFREELIST_MAX ||
- !listAddNodeHead(server.objfreelist,o))
- zfree(o);
- if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
+ zfree(o);
}
}
* range and if this is the main thread, since when VM is enabled we
* have the constraint that I/O thread should only handle non-shared
* objects, in order to avoid race conditions (we don't have per-object
- * locking). */
- if (value >= 0 && value < REDIS_SHARED_INTEGERS &&
+ * locking).
+ *
+ * Note that we also avoid using shared integers when maxmemory is used
+ * because very object needs to have a private LRU field for the LRU
+ * algorithm to work well. */
+ if (server.maxmemory == 0 && value >= 0 && value < REDIS_SHARED_INTEGERS &&
pthread_equal(pthread_self(),server.mainthread)) {
decrRefCount(o);
incrRefCount(shared.integers[value]);
default: return "unknown";
}
}
+
+/* Given an object returns the min number of seconds the object was never
+ * requested, using an approximated LRU algorithm. */
+unsigned long estimateObjectIdleTime(robj *o) {
+ if (server.lruclock >= o->lru) {
+ return (server.lruclock - o->lru) * REDIS_LRU_CLOCK_RESOLUTION;
+ } else {
+ return ((REDIS_LRU_CLOCK_MAX - o->lru) + server.lruclock) *
+ REDIS_LRU_CLOCK_RESOLUTION;
+ }
+}