From: Thomas Gleixner <tglx@linutronix.de>
To: Dave Jones <davej@codemonkey.org.uk>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>, x86@kernel.org
Subject: Re: weird DirectMap2M accounting.
Date: Mon, 11 Jan 2016 09:58:01 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.11.1601110957390.3575@nanos> (raw)
In-Reply-To: <20160107001850.GA7443@codemonkey.org.uk>
On Wed, 6 Jan 2016, Dave Jones wrote:
> On Wed, Jan 06, 2016 at 07:11:41PM -0500, Dave Jones wrote:
> > On Wed, Jan 06, 2016 at 06:55:27PM -0500, Dave Jones wrote:
> > > I just spotted this in /proc/meminfo on an old Core2 machine with 4G.
> > >
> > > DirectMap2M: 18446744073709543424 kB
> > >
> > > Looks like we subtracted 8192 from 0 somewhere.
> > >
> > > Should split_page_count() be checking that direct_pages_count > 0 ?
> >
> > Ok, this diff makes that number print out as 0.
> >
> > If this looks ok, I'll submit it properly, though I'd like to better
> > understand what's happening here. Shouldn't I have 2M pages ?
>
> Ah. We disable them when compiling with DEBUG_PAGEALLOC.
> So this is only needed in that case.
> If people think it's worth an ifdef for those two added lines I'll add it,
> but it seems pretty benign to just always check.
Agreed.
tglx
prev parent reply other threads:[~2016-01-11 8:58 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-06 23:55 Dave Jones
2016-01-07 0:11 ` Dave Jones
2016-01-07 0:18 ` Dave Jones
2016-01-11 8:58 ` Thomas Gleixner [this message]
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