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From: David Rientjes <rientjes@google.com>
To: Christoph Lameter <clameter@sgi.com>
Cc: Andrew Morton <akpm@osdl.org>, Hugh Dickins <hugh@veritas.com>,
	Paul Mundt <lethal@linux-sh.org>,
	Paul Davies <pauld@cse.unsw.edu.au>,
	linux-kernel@vger.kernel.org
Subject: Re: [patch 1/3 take2] smaps: extract pte walker from smaps code
Date: Wed, 7 Feb 2007 01:35:31 -0800 (PST)	[thread overview]
Message-ID: <Pine.LNX.4.64.0702070124210.22710@chino.kir.corp.google.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0702070017360.26926@schroedinger.engr.sgi.com>

On Wed, 7 Feb 2007, Christoph Lameter wrote:

> Clearing reference bits? Ummm... That is a pretty inaccurate measure since 
> reclaim can remove pages and revert the reference bits. It can never work 
> reliably.
> 

It's not intended to work precisely, it's intended to give a good estimate 
of task memory footprint.  There are several different scenarios that can 
interfere with getting a precise measurement via this method; then again 
/proc/pid/smaps is so expensive already because of the iteration through 
VMA's that it's not something you'd do regularly.

Any other suggestions on how to obtain this data is certainly welcome.

> Would it be possible to sync up with the people doing the page table 
> interface?
> 

(+pauld)

Is there an update on Paul Davies' implementation that would allow us to 
iterate through a set of pte's in a vm_area_struct range?

> Could we somehow consolidate smaps and numa_maps?
> 

Sure, but that's beyond the scope of this patchset.  My intention in 
extracting away a new pte_walker was to prevent having two identical 
implementations and it could easily be extracted even further to lib for 
the ioremap case that Paul mentioned.

		David

  reply	other threads:[~2007-02-07  9:35 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-07  6:15 David Rientjes
2007-02-07  6:15 ` [patch 2/3 take2] smaps: add pages referenced count to smaps David Rientjes
2007-02-07  6:15   ` [patch 3/3 take2] smaps: add clear_refs file to clear reference David Rientjes
2007-02-07  6:33     ` Andrew Morton
2007-02-07  6:29 ` [patch 1/3 take2] smaps: extract pte walker from smaps code Paul Mundt
2007-02-07  6:49   ` Andrew Morton
2007-02-07  7:24     ` Paul Mundt
2007-02-09  2:00   ` Matt Mackall
2007-02-09  2:25     ` David Rientjes
2007-02-07  8:30 ` Christoph Lameter
2007-02-07  9:35   ` David Rientjes [this message]
2007-02-09 16:15   ` Matt Mackall

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