Two reasons
1. Some (potentially quite a bit) of the memory is needed for kernel
side resources - page tables, disk cache, kernel image, network
buffers etc
2. Keeping pages both in memory and on swap is good. The swap cache
massively reduces disk reads to memory.
Alan
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/