Re: Virtually Mapped Stacks: Do not disable interrupts

[Andy Lutomirski]

On Wed, May 17, 2017 at 8:58 AM, Christoph Lameter <cl@xxxxxxxxx> wrote:
> The reason to disable interrupts seems to be to avoid switching
> to a different processor while handling per cpu data using
> individual loads and stores. If we use per cpu RMV primitives
> we will not have to disable interrupts.

I like this, except that those primitives can be quite expensive, I
think, and they're being called in a loop.  What if you first did a
this_cpu_read() to see if the value in the cache slot might be useful
before doing the heavyweight exchange?

--Andy