Weird kernel.shmax value [duplicate]

I've noticed that kernel.shmmax value is set to oddly huge number on my RHEL 7 system.

# sysctl kernel.shmmax kernel.shmmax = 18446744073692774399 

1. Is it OK to have such a huge number set?
2. How can it affect the system?
3. What exactly that parameter means?

Some info about the system:

 # cat /etc/redhat-release Red Hat Enterprise Linux Server release 7.2 (Maipo) # cat /proc/meminfo MemTotal: 9037028 kB MemFree: 175220 kB MemAvailable: 2544492 kB Buffers: 0 kB Cached: 2716836 kB SwapCached: 14908 kB Active: 5749708 kB Inactive: 2371364 kB Active(anon): 4490064 kB Inactive(anon): 1120848 kB Active(file): 1259644 kB Inactive(file): 1250516 kB Unevictable: 10800 kB Mlocked: 10796 kB SwapTotal: 5242876 kB SwapFree: 5143688 kB Dirty: 9704 kB Writeback: 0 kB AnonPages: 5400268 kB Mapped: 318000 kB Shmem: 202700 kB Slab: 379036 kB SReclaimable: 169128 kB SUnreclaim: 209908 kB KernelStack: 34080 kB PageTables: 46252 kB NFS_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB CommitLimit: 9761388 kB Committed_AS: 7599336 kB VmallocTotal: 34359738367 kB VmallocUsed: 181868 kB VmallocChunk: 34359341052 kB HardwareCorrupted: 0 kB AnonHugePages: 1861632 kB HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB DirectMap4k: 92096 kB DirectMap2M: 9345024 kB 

# uname -a Linux hostname 3.10.0-693.21.1.el7.AV1.x86_64 #1 SMP Thursday April 5, 2018 09:26:08 MDT x86_64 x86_64 x86_64 GNU/Linux 

Well, kernel.shmall parameter has the same value.

$ sysctl -a | grep shm kernel.shmall = 18446744073692774399 kernel.shmmax = 18446744073692774399 kernel.shmmni = 4096 

Thanks in advance!