Dirty private memory is all memory in non-inode-backed mappings that's
process-private, meaning it's not shared with any other process.
This patch exposes that number via SystemMonitor, giving us an idea of
how much memory each process is responsible for all on its own.
Every process keeps its own ELF executable mapped in memory in case we
need to do symbol lookup (for backtraces, etc.)
Until now, it was mapped in a way that made it accessible to the
program, despite the program not having mapped it itself.
I don't really see a need for userspace to have access to this right
now, so let's lock things down a little bit.
This patch makes it inaccessible to userspace and exposes that fact
through /proc/PID/vm (per-region "user_accessible" flag.)
This patch exposes some fields about purgeable memory regions.
We now also show total purgeable volatile and non-volatile memory in
the big process table.
