diff --git a/src/object.c b/src/object.c index 24e99d191..234e11f8a 100644 --- a/src/object.c +++ b/src/object.c @@ -1199,7 +1199,7 @@ sds getMemoryDoctorReport(void) { /* Set the object LRU/LFU depending on server.maxmemory_policy. * The lfu_freq arg is only relevant if policy is MAXMEMORY_FLAG_LFU. - * The lru_idle and lru_clock args are only relevant if policy + * The lru_idle and lru_clock args are only relevant if policy * is MAXMEMORY_FLAG_LRU. * Either or both of them may be <0, in that case, nothing is set. */ void objectSetLRUOrLFU(robj *val, long long lfu_freq, long long lru_idle, @@ -1210,16 +1210,20 @@ void objectSetLRUOrLFU(robj *val, long long lfu_freq, long long lru_idle, val->lru = (LFUGetTimeInMinutes()<<8) | lfu_freq; } } else if (lru_idle >= 0) { - /* Serialized LRU idle time is in seconds. Scale + /* Provided LRU idle time is in seconds. Scale * according to the LRU clock resolution this Redis * instance was compiled with (normally 1000 ms, so the * below statement will expand to lru_idle*1000/1000. */ lru_idle = lru_idle*1000/LRU_CLOCK_RESOLUTION; - val->lru = lru_clock - lru_idle; - /* If the lru field overflows (since LRU it is a wrapping - * clock), the best we can do is to provide the maximum - * representable idle time. */ - if (val->lru < 0) val->lru = lru_clock+1; + long lru_abs = lru_clock - lru_idle; /* Absolute access time. */ + /* If the LRU field underflows (since LRU it is a wrapping + * clock), the best we can do is to provide a large enough LRU + * that is half-way in the circlular LRU clock we use: this way + * the computed idle time for this object will stay high for quite + * some time. */ + if (lru_abs < 0) + lru_abs = (lru_clock+(LRU_CLOCK_MAX/2)) % LRU_CLOCK_MAX; + val->lru = lru_abs; } }