Re: [PATCH 0/2][RFC] VFCIPI v3

[Peter Zijlstra <peterz@infradead.org>]

Hi Gregory,

This patch set approaches the problem from the wrong angle (and has a
few problems due to that).

The idea to use a workqueue (or in your case workqueue-like) solution to
the problem is valid, however instead of re-using (and improving) the
current workqueue infrastructure, you re-implement it (with mistakes).

The solution currently in -rt uses regular workqueues to implement
schedule_on_each_cpu() - a drop in replacement for on_each_cpu() in the
context of -rt and useful outside of that if people do require such
functionality.

Your idea of using priority arrays in the workqueue is a good one,
please implement that for the regular workqueues.

Your idea that GFP_ATOMIC is broken in -rt is unfortunate, it isn't. The
whole allocator is preemptable - that is a feature!

Please keep up the good work, looking forward to those prio-workqueue
patches.

Peter