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Date: Sun, 1 Nov 2009 18:53:45 +0300
From: Alexey Dobriyan <adobriyan@gmail.com>
To: Stefani Seibold <stefani@seibold.net>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] proc: remove /proc/*/status "Stack usage:"
Message-ID: <20091101155345.GA3867@x200>
References: <20091101131518.GA18284@x200>
 <1257086397.31587.5.camel@wall-e>
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On Sun, Nov 01, 2009 at 03:39:57PM +0100, Stefani Seibold wrote:
> Am Sonntag, den 01.11.2009, 16:15 +0300 schrieb Alexey Dobriyan:
> > We have /proc/*/pagemap to determine how much stack was consumed.
> > Leave "threadstack" though.
> > 
> > Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> > ---
> > 
> 
> Stop! /proc/*/pagemap is not a real substitute for the stackm usage
> patch. If you have problems with this patch i will have a look on it.

Why?

You grab thread stack start from /proc/*/stat, then for every page of
stack VMA, you lookup state of page, which is exactly what you're doing
by employing page walker.