Re: [PATCH v13 00/12] support "task_isolation" mode

On Thu, Jul 14, 2016 at 2:22 PM, Chris Metcalf [off-list ref] wrote:

On 7/14/2016 5:03 PM, Andy Lutomirski wrote:

quoted

On Thu, Jul 14, 2016 at 1:48 PM, Chris Metcalf [off-list ref]
wrote:

quoted

Here is a respin of the task-isolation patch set.  This primarily
reflects feedback from Frederic and Peter Z.

I still think this is the wrong approach, at least at this point.  The
first step should be to instrument things if necessary and fix the
obvious cases where the kernel gets entered asynchronously.

Note, however, that the task_isolation_debug mode is a very convenient
way of discovering what is going on when things do go wrong for task
isolation.

quoted

Only once
there's a credible reason to believe it can work well should any form
of strictness be applied.

I'm not sure what criteria you need for this, though.  Certainly we've been
shipping our version of task isolation to customers since 2008, and there
are quite a few customer applications in production that are working well.
I'd argue that's a credible reason.

quoted

As an example, enough vmalloc/vfree activity will eventually cause
flush_tlb_kernel_range to be called and *boom*, there goes your shiny
production dataplane application.

Well, that's actually a refinement that I did not inflict on this patch
series.

Submit it separately, perhaps?

The "kill the process if it goofs" think while there are known goofs
in the kernel, apparently with patches written but unsent, seems
questionable.