linux-kernel - fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle)

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Date:	Sat, 23 Jan 2016 17:21:55 +0100
From:	Mike Galbraith <umgwanakikbuti@...il.com>
To:	Christoph Lameter <cl@...ux.com>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: fast path cycle muncher (vmstat: make vmstat_updater deferrable
 again and shut down on idle)

Hi Christoph,

While you're fixing that commit up, can you perhaps find a better home
for quiet_vmstat()?  It not only munches cycles when switching cross
-core mightily, for -rt it injects a sleeping lock into the idle task.

    12.89%  [kernel]       [k] refresh_cpu_vm_stats.isra.12
     4.75%  [kernel]       [k] __schedule                  
     4.70%  [kernel]       [k] mutex_unlock                
     3.14%  [kernel]       [k] __switch_to                 

	-Mike