linux-kernel - Re: bad page state in 3.13-rc4

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Message-ID: <20131219204206.GC10905@kvack.org>
Date:	Thu, 19 Dec 2013 15:42:06 -0500
From:	Benjamin LaHaise <bcrl@...ck.org>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Kent Overstreet <kmo@...erainc.com>, Dave Jones <davej@...hat.com>,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	linux-mm <linux-mm@...ck.org>, Christoph Lameter <cl@...two.org>,
	Al Viro <viro@...iv.linux.org.uk>
Subject: Re: bad page state in 3.13-rc4

On Fri, Dec 20, 2013 at 05:31:29AM +0900, Linus Torvalds wrote:
> On Fri, Dec 20, 2013 at 5:11 AM, Linus Torvalds
> <torvalds@...ux-foundation.org> wrote:
> >
> > So here's the same patch, but with stuff moved around a bit, and the
> > "oops, couldn't create page" part fixed.
> >
> > Bit it's still totally and entirely untested.
> 
> Btw, I think this actually fixes a bug, in that it doesn't leak the
> page reference count if the do_mmap_pgoff() call fails.
> 
> That said, that looks like just a memory leak, not explaining the
> problem Dave sees. And maybe I'm missing something.
> 
> And no, I still haven't actually tested this at all. Is there an aio
> tester that is worth trying?

There are a few tests in the libaio source, some in xfstests and fio, and 
a few I've got sitting around.  To specifically exercise the page migration 
code path, there's a test at http://www.kvack.org/~bcrl/aio-numa-test.c .

		-ben

>                    Linus

-- 
"Thought is the essence of where you are now."
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