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Date: Mon, 6 Nov 2017 09:38:44 -0600 (CST)
From: Christopher Lameter <cl@linux.com>
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To: Chris Metcalf <cmetcalf@mellanox.com>
cc: Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@kernel.org>,
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Subject: Re: [PATCH v16 00/13] support "task_isolation" mode
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On Fri, 3 Nov 2017, Chris Metcalf wrote:

> However, it doesn't seem possible to do the synchronous cancellation of
> the vmstat deferred work with irqs disabled, though if there's a way,
> it would be a little cleaner to do that; Christoph?  We can certainly
> update the statistics with interrupts disabled via
> refresh_cpu_vm_stats(false), but that's not sufficient.  For now, I

Callig quiet_vmstat() gives you the folding of the statistics without
the numa page allocator page cleanup. Leaving some pages in the queues
should not be that much of an issue.

> What about that d*mn 1 Hz clock?
>
> It's still there, so this code still requires some further work before
> it can actually get a process into long-term task isolation (without
> the obvious one-line kernel hack).  Frederic suggested a while ago
> forcing updates on cpustats was required as the last gating factor; do
> we think that is still true?  Christoph was working on this at one
> point - any progress from your point of view?

Well if you still have the 1 HZ clock then you can simply defer the numa
remote page cleanup of the page allocator to that the time you execute
that tick.