Is there kernel patch to prevent load files into RAM for LiveCD?
I mean, if I'm use LiveCD with "boot to Ram" option, there is no needs for kernel to load executable binaries to RAM from RAM.
It would greatly decrease RAM usage for LiveCD.
E.g. modern Linux distributive with even openoffice may be less than 2Gb. Modern Personal Computer with 4Gb may load whole of such distributive into RAM to increase speed in 1000x, but logs and temporary files with some snapshots puts to hard drive.
On some embedded architectures, the kernel supports execute in-place (XIP). It's not appropriate for LiveCDs, because these use squashfs and union mounts, and you need a decompressed copy of the data. CDs are also particularly slow; use a swap partition (possibly with zswap) if you don't have a lot of memory and want the kernel to be able to page out infrequently used pages.
I think you don't understand how Live CDs work. When you boot, the CD gets mounted readonly. Then there's a squashfs union-mounted on top, mounted read-write. This means that the entire CD does not, in fact, get loaded into RAM. Therefore, executables aren't automatically in RAM and you still need to load them.
