[RFC PATCH] uprobes: copy to user-space xol page with proper cache flushing

[Oleg Nesterov]

On 04/11, Victor Kamensky wrote:
>
> On 11 April 2014 11:02, David Miller <davem at davemloft.net> wrote:
> But in uprobes case xol slot where instruction write happened will be
> used only by current CPU. The way I read uprobes code other core
> when it hit the same uprobe address will use different xol slot. Xol slot
> size is cache line so it will not be moved around.

Yes.

> So as long as we
> know for sure that while tasks performs single step on uprobe xol
> area instruction it won't be migrated to another core we don't need to
> do broadcast to any other cores.

It can migrate to another CPU before it does single-step.

Oleg.