The whole point of my comment is that PHK's analysis leaves out many downsides of leaving it all to the kernel. His main argument against doing it is user-spac

The whole point of my comment is that PHK's analysis leaves out many downsides of leaving it all to the kernel. His main argument against doing it is user-space is that you will "fight with the kernel's elaborate memory management." But if you just turn off swap completely and read files with read/write instead of mmap(), there is no fight. Everything happens in user-space. Leaving it all to the kernel has many disadvantages as I spent many paragraphs explaining.