Function rdbSaveBackground

app/redis-6.2.6/src/rdb.c:1423–1457

}

int rdbSaveBackground(char *filename, rdbSaveInfo *rsi) {
    pid_t childpid;

    if (hasActiveChildProcess()) return C_ERR;

    server.dirty_before_bgsave = server.dirty;
    server.lastbgsave_try = time(NULL);

    if ((childpid = redisFork(CHILD_TYPE_RDB)) == 0) {
        int retval;

        /* Child */
        redisSetProcTitle("redis-rdb-bgsave");
        // resetCpuAffinity();
        redisSetCpuAffinity(server.bgsave_cpulist);
        retval = rdbSave(filename,rsi);
        if (retval == C_OK) {
            sendChildCowInfo(CHILD_INFO_TYPE_RDB_COW_SIZE, "RDB");
        }
        exitFromChild((retval == C_OK) ? 0 : 1);
    } else {
        /* Parent */
        if (childpid == -1) {
            server.lastbgsave_status = C_ERR;
            serverLog(LL_WARNING,"Can't save in background: fork: %s",
                strerror(errno));
            return C_ERR;
        }
        serverLog(LL_NOTICE,"Background saving started by pid %ld",(long) childpid);
        server.rdb_save_time_start = time(NULL);
        server.rdb_child_type = RDB_CHILD_TYPE_DISK;
        return C_OK;
    }
    return C_OK; /* unreached */
}

/* Note that we may call this function in signal handle 'sigShutdownHandler',
 * so we need guarantee all functions we call are async-signal-safe.