Function getMemoryOverheadData

app/redis-6.2.6/src/object.c:981–1082

Return a struct redisMemOverhead filled with memory overhead * information used for the MEMORY OVERHEAD and INFO command. The returned * structure pointer should be freed calling freeMemoryOverheadData(). */

 * information used for the MEMORY OVERHEAD and INFO command. The returned
 * structure pointer should be freed calling freeMemoryOverheadData(). */
struct redisMemOverhead *getMemoryOverheadData(void) {
    int j;
    size_t mem_total = 0;
    size_t mem = 0;
    size_t zmalloc_used = zmalloc_used_memory();
    struct redisMemOverhead *mh = zcalloc(sizeof(*mh));

    mh->total_allocated = zmalloc_used;
    mh->startup_allocated = server.initial_memory_usage;
    mh->peak_allocated = server.stat_peak_memory;
    mh->total_frag =
        (float)server.cron_malloc_stats.process_rss / server.cron_malloc_stats.zmalloc_used;
    mh->total_frag_bytes =
        server.cron_malloc_stats.process_rss - server.cron_malloc_stats.zmalloc_used;
    mh->allocator_frag =
        (float)server.cron_malloc_stats.allocator_active / server.cron_malloc_stats.allocator_allocated;
    mh->allocator_frag_bytes =
        server.cron_malloc_stats.allocator_active - server.cron_malloc_stats.allocator_allocated;
    mh->allocator_rss =
        (float)server.cron_malloc_stats.allocator_resident / server.cron_malloc_stats.allocator_active;
    mh->allocator_rss_bytes =
        server.cron_malloc_stats.allocator_resident - server.cron_malloc_stats.allocator_active;
    mh->rss_extra =
        (float)server.cron_malloc_stats.process_rss / server.cron_malloc_stats.allocator_resident;
    mh->rss_extra_bytes =
        server.cron_malloc_stats.process_rss - server.cron_malloc_stats.allocator_resident;

    mem_total += server.initial_memory_usage;

    mem = 0;
    if (server.repl_backlog)
        mem += zmalloc_size(server.repl_backlog);
    mh->repl_backlog = mem;
    mem_total += mem;

    /* Computing the memory used by the clients would be O(N) if done
     * here online. We use our values computed incrementally by
     * clientsCronTrackClientsMemUsage(). */
    mh->clients_slaves = server.stat_clients_type_memory[CLIENT_TYPE_SLAVE];
    mh->clients_normal = server.stat_clients_type_memory[CLIENT_TYPE_MASTER]+
                         server.stat_clients_type_memory[CLIENT_TYPE_PUBSUB]+
                         server.stat_clients_type_memory[CLIENT_TYPE_NORMAL];
    mem_total += mh->clients_slaves;
    mem_total += mh->clients_normal;

    mem = 0;
    if (server.aof_state != AOF_OFF) {
        mem += sdsZmallocSize(server.aof_buf);
        mem += aofRewriteBufferSize();
    }
    mh->aof_buffer = mem;
    mem_total+=mem;

    mem = server.lua_scripts_mem;
    mem += dictSize(server.lua_scripts) * sizeof(dictEntry) +
        dictSlots(server.lua_scripts) * sizeof(dictEntry*);
    mem += dictSize(server.repl_scriptcache_dict) * sizeof(dictEntry) +
        dictSlots(server.repl_scriptcache_dict) * sizeof(dictEntry*);