Re: Udpated sys_membarrier() speedup patch, FYI

From: Avi Kivity
Date: Mon Jul 31 2017 - 04:54:09 EST


On 07/31/2017 11:37 AM, Peter Zijlstra wrote:
On Mon, Jul 31, 2017 at 09:03:09AM +0300, Avi Kivity wrote:
I remembered that current->mm does not change when switching to a kernel
task, but my Kernlish is very rusty, or maybe it has changed.
kernel threads do indeed preserve the mm of the old userspace task, but
we track that in ->active_mm. Their ->mm will be NULL.

Gah, I'm so rusty, if I were any rustier I'd be doing bitcoin.