Re: [GIT PULL] device-dax for 5.1: PMEM as RAM

From: Linus Torvalds
Date: Sun Mar 10 2019 - 16:02:05 EST

On Sun, Mar 10, 2019 at 12:54 PM Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
> Hi Linus, please pull from:
> git://
> tags/devdax-for-5.1
> receive new device-dax infrastructure to allow persistent memory
> and other "reserved" / performance differentiated memories, to be
> assigned to the core-mm as "System RAM".

I'm not pulling this until I get official Intel clarification on the
whole "pmem vs rep movs vs machine check" behavior.

Last I saw it was deadly and didn't work, and we have a whole "mc-safe
memory copy" thing for it in the kernel because repeat string
instructions didn't work correctly on nvmem.

No way am I exposing any users to something like that.

We need a way to know when it works and when it doesn't, and only do
it when it's safe.