linux-kernel - excessive kworker activity when idle. (was Re: vma corruption in today's -git)

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Date:	Wed, 30 Mar 2011 23:09:18 -0400
From:	Dave Jones <davej@...hat.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: excessive kworker activity when idle. (was Re: vma corruption in
 today's -git)

On Mon, Mar 28, 2011 at 09:22:25PM -0700, Linus Torvalds wrote:
 > On Mon, Mar 28, 2011 at 9:09 PM, Dave Jones <davej@...hat.com> wrote:
 > >
 > > I ran perf top, and got this ..
 > >
 > >  BUG: unable to handle kernel paging request at fffffffffffffff3
 > 
 > Should be fixed by commit 76597cd31470.
 > 
 > Except that was already committed yesterday. When did you pull?

It did fix it, I must have missed that commit.

But rerunning the same tests on current head (6aba74f2791287ec407e0f92487a725a25908067)
I can still reproduce the problem where kworker threads go nutso
when the machine should be completely idle.

top shows two kworker threads constantly at >80% cpu.

I can now profile it with perf though, so I'll dig deeper.
I need to try a build with slab debug etc turned off, just to be sure that
isn't throwing things into a spin.

	Dave

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