linux-kernel - Re: [PATCH] proc: remove /proc/*/status "Stack usage:"

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Message-ID: <1257118328.7978.9.camel@wall-e>
Date:	Mon, 02 Nov 2009 00:32:08 +0100
From:	Stefani Seibold <stefani@...bold.net>
To:	Alexey Dobriyan <adobriyan@...il.com>
Cc:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] proc: remove /proc/*/status "Stack usage:"

Am Sonntag, den 01.11.2009, 18:53 +0300 schrieb Alexey Dobriyan:
> 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.
> > > 
> > 
> > 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.

First, as you figured out there is currently no way to get the stack
start of a thread. But i currently check this and hope to find a
solution in the next 24 hours.

Second, this patch aims to the embedded world and there is normally no
tools available when you need it, but /proc is always there. Especially
outside in the field.

Like Dr Frank. N. Furter in the "Rocky Horror Picture Show" says: remove
the cause but NOT the symptoms!

And the cause is the miss implemented KSTK_ESP in a x86_64. I also
checked all other architekture depended KSTK_ESP definitions and this
definitions looks okay for me. 

Stand by....

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