From: Andrew Morton <akpm@linux-foundation.org>
To: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux-foundation.org>,
Mel Gorman <mel@csn.ul.ie>,
linux-mm@kvack.org
Subject: Re: [patch] mm: suppress pfn range output for zones without pages
Date: Thu, 11 Feb 2010 14:33:01 -0800 [thread overview]
Message-ID: <20100211143301.6099fed3.akpm@linux-foundation.org> (raw)
In-Reply-To: <alpine.DEB.2.00.1002111405120.16763@chino.kir.corp.google.com>
On Thu, 11 Feb 2010 14:13:19 -0800 (PST)
David Rientjes <rientjes@google.com> wrote:
> On Thu, 11 Feb 2010, Christoph Lameter wrote:
>
> > > The output is now suppressed for zones that do not have a valid pfn
> > > range.
> >
> > There is a difference between zone support not compiled into the kernel
> > and the zone being empty. The output so far allows me to see that support
> > for a zone was compiled into the kernel but it is empty.
> >
>
> So you want to parse this table of zone pfn ranges to determine, for
> example, whether CONFIG_HIGHMEM was enabled for i386 kernels? That
> doesn't tell you whether its CONFIG_HIGHMEM4G or CONFIG_HIGHMEM64G, so
> it's a pretty bad way to interpret the kernel config and decide whether
> the pfn ranges are valid or not. The only other use case would be to find
> if the values are sane when we don't have CONFIG_ZONE_DMA or
> CONFIG_ZONE_DMA32, but those typically aren't even disabled: I just sent a
> patch to the x86 maintainers to get that configuration to compile on -rc7.
>
> In other words, I don't think we need to be emitting kernel diagnostic
> messages for zones that are empty and unused just because they are enabled
> in the kernel config; no developer is going to care about parsing the
> usecase I showed in the changelog since ZONE_NORMAL is always defined.
It also tells us that the zone was represented in BIOS tables, but is
empty.
Perhaps the zone is always represented in BIOS tables (or the equiv for
other architectures), dunno. If so, that's not information.
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prev parent reply other threads:[~2010-02-11 22:33 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-11 9:29 [patch] mm: suppress pfn range output for zones without pages David Rientjes
2010-02-11 12:25 ` Mel Gorman
2010-02-11 21:26 ` David Rientjes
2010-02-11 22:27 ` Andrew Morton
2010-02-11 20:07 ` Christoph Lameter
2010-02-11 22:13 ` David Rientjes
2010-02-11 22:32 ` Christoph Lameter
2010-02-11 23:02 ` [patch v2] " David Rientjes
2010-02-12 15:44 ` Christoph Lameter
2010-02-11 22:33 ` Andrew Morton [this message]
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