Re: [PATCH 4/8] proc: export more page flags in /proc/kpageflags

From: Ingo Molnar
Date: Fri May 08 2009 - 07:48:31 EST



* Wu Fengguang <fengguang.wu@xxxxxxxxx> wrote:

> Export all page flags faithfully in /proc/kpageflags.

Ongoing objection and NAK against extended haphazard exporting of
kernel internals via an ad-hoc ABI via ad-hoc, privatized
instrumentation that only helps the MM code and nothing else. It was
a mistake to introduce the /proc/kpageflags hack a year ago, and it
even more wrong today to expand on it.

/proc/kpageflags should be done via the proper methods outlined in
the previous mails i wrote on this topic: for example by using the
'object collections' abstraction i suggested. Clean enumeration of
all pages (files, tasks, etc.) and the definition of histograms over
it via free-form filter expressions is the right way to do this. It
would not only help other subsystems, it would also be far more
capable.

So this should be done in cooperation with instrumentation folks,
while improving _all_ of Linux instrumentation in general. Or, if
you dont have the time/interest to work with us on that, it should
not be done at all. Not having the resources/interest to do
something properly is not a license to introduce further
instrumentation crap into Linux.

Ingo
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