diff options
Diffstat (limited to 'src/redis.c')
| -rw-r--r-- | src/redis.c | 68 |
1 files changed, 63 insertions, 5 deletions
diff --git a/src/redis.c b/src/redis.c index fbe8a8822..d07bb7c58 100644 --- a/src/redis.c +++ b/src/redis.c @@ -1433,8 +1433,8 @@ void initServerConfig(void) { server.maxclients = REDIS_MAX_CLIENTS; server.bpop_blocked_clients = 0; server.maxmemory = REDIS_DEFAULT_MAXMEMORY; - server.maxmemory_enforced = REDIS_DEFAULT_MAXMEMORY; - server.maxmemory_adjusted = REDIS_DEFAULT_MAXMEMORY; + server.maxmemory_frag_guess = REDIS_DEFAULT_MAXMEMORY_FRAG_GUESS; + server.maxmemory_enforced = (double) REDIS_DEFAULT_MAXMEMORY / server.maxmemory_frag_guess; server.maxmemory_policy = REDIS_DEFAULT_MAXMEMORY_POLICY; server.maxmemory_samples = REDIS_DEFAULT_MAXMEMORY_SAMPLES; server.rss_aware_maxmemory = REDIS_DEFAULT_RSS_AWARE_MAXMEMORY; @@ -3157,7 +3157,7 @@ void evictionPoolPopulate(dict *sampledict, dict *keydict, struct evictionPoolEn } int freeMemoryIfNeeded(void) { - size_t mem_used, mem_tofree, mem_freed; + size_t mem_used, mem_tofree, mem_freed, mem_target = server.maxmemory; int slaves = listLength(server.slaves); mstime_t latency; @@ -3183,14 +3183,72 @@ int freeMemoryIfNeeded(void) { mem_used -= aofRewriteBufferSize(); } + /* If we use RSS aware maxmemory, update the target memory using + * the current fragmentation figure. */ +#ifdef HAVE_RSS_REPORTING + if (server.rss_aware_maxmemory && + server.maxmemory_policy != REDIS_MAXMEMORY_NO_EVICTION) + { + static unsigned long iterations = 0; + static unsigned long sampling_stage = 1; + static float last_observed_frag = 0; + + /* For some time, we analyze what happens during memory pressure, when + * objects are evicted and reallocated. */ + if (mem_used > server.maxmemory_enforced) { + unsigned long sample_cycles = 1000000; + + /* Every sample_cycle cycles we sample the fragmentation, and + * compare it with the previos one. If it is no longer raising, + * we take it as a guess of the fragmentation with this workload. */ + if (sampling_stage && iterations < sample_cycles) { + iterations++; + if (iterations == sample_cycles) { + float current_frag = zmalloc_get_fragmentation_ratio(server.resident_set_size); + if (last_observed_frag == 0) { + /* First sample we get. */ + last_observed_frag = current_frag; + } else { + if (current_frag <= last_observed_frag) { + size_t enforced_new; + + sampling_stage = 0; + server.maxmemory_frag_guess = current_frag; + /* Update the global fragmentation guess and use + * it (also used it for successive + * "CONFIG SET maxmemory" commands). */ + if (server.maxmemory_frag_guess < 1) + server.maxmemory_frag_guess = 1; + else if (server.maxmemory_frag_guess > 2) + server.maxmemory_frag_guess = 2; + + /* Only set the new limit if it is higher than our + * initial guess, otherwise it is futile: RSS will + * not go backward anyway. */ + enforced_new = (double) server.maxmemory / + server.maxmemory_frag_guess; + if (enforced_new > server.maxmemory_enforced) + server.maxmemory_enforced = enforced_new; + redisLog(REDIS_NOTICE,"RSS aware maxmemory, fragmentation looks stable at: %f", server.maxmemory_frag_guess); + } + last_observed_frag = current_frag; + } + iterations = 0; + } + } + } + mem_target = server.maxmemory_enforced; + } +#endif + /* Check if we are over the memory limit. */ - if (mem_used <= server.maxmemory) return REDIS_OK; + if (mem_used <= mem_target) return REDIS_OK; if (server.maxmemory_policy == REDIS_MAXMEMORY_NO_EVICTION) return REDIS_ERR; /* We need to free memory, but policy forbids. */ /* Compute how much memory we need to free. */ - mem_tofree = mem_used - server.maxmemory; + mem_tofree = mem_used - mem_target; mem_freed = 0; latencyStartMonitor(latency); while (mem_freed < mem_tofree) { |