What is memory reclaim in linux

I am very new to Linux memory management concept while reading some memory management related document I had some basic doubt please clarify me.

considering below is my config

vm.swappiness=10vm.vfs_cache_pressure=140vm.min_free_kbytes=2013265 

My understanding if free memory is gone less than vm.min_free_kbytes OS will reclaim the memory.

1- Is Memory reclaim is a deletion of unwanted file or copying to Swap memory from RAM?

2- If it's copying to Swap memory from RAM, then if I am not using SWAP memory what will be happened?

3- Is swappiness is always greater than the vm.min_free_kbytes?

4-What the significants of vm.vfs_cache_pressure ?

Thank You..!!