Re: [PATCH 2/2] mm: adds NOSIGBUS extension for out-of-band shmem read

[Simon Ser]

On Thursday, June 3rd, 2021 at 9:24 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:

> I don’t understand the use case well enough to comment on whether MAP_PRIVATE
> is sufficient, but I’m with Hugh: if this feature is implemented for
> MAP_SHARED, it should be fully coherent.

I've tried to explain what we'd need from user-space PoV in [1].
tl;dr the MAP_PRIVATE restriction would get us pretty far, even if it
won't allow us to have all of the bells and whistles.

[1]: https://lore.kernel.org/linux-mm/vs1Us2sm4qmfvLOqNat0-r16GyfmWzqUzQ4KHbXJwEcjhzeoQ4sBTxx7QXDG9B6zk5AeT7FsNb3CSr94LaKy6Novh1fbbw8D_BBxYsbPLms=@emersion.fr/T/#mb321a8d39e824740877ba95f1df780ffd52c3862