> -----Original Message-----
> From: Xen-devel <[email protected]> On Behalf Of Julien
> Grall
> Sent: 11 September 2020 17:34
> To: [email protected]; [email protected]
> Cc: Roger Pau Monné <[email protected]>; Bertrand Marquis
> <[email protected]>
> Subject: Adopting the Linux Kernel Memory Model in Xen?
>
> Hi all,
>
> At the moment, Xen doesn't have a formal memory model. Instead, we are
> relying on intuitions. This can lead to heated discussion on what can a
> processor/compiler do or not.
>
...which, in turn, may well lead us into decisions that harm performance.
> We also have some helpers that nearly do the same (such as
> {read,write}_atomic() vs ACCESS_ONCE()) with no clear understanding
> where to use which.
>
> In the past few years, Linux community spent a lot of time to write down
> their memory model and make the compiler communities aware of it (see
> [1], [2]).
>
> There are a few reasons I can see for adopting LKMM:
> - Xen borrows a fair amount of code from Linux;
...and essentially the same toolchain(s)
> - There are efforts to standardize it;
> - This will allow us to streamline the discussion.
>
> Any thoughts?
>
It seems like a very good idea to me.
Paul
> Cheers,
>
> [1] https://www.kernel.org/doc/Documentation/memory-barriers.txt
> [2] http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p0124r7.html
>
>
> --
> Julien Grall
