linux-kernel - Re: [patch] tracing/mm: add page frame snapshot trace

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20090509092431.GB13784@elte.hu>
Date:	Sat, 9 May 2009 11:24:31 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Wu Fengguang <fengguang.wu@...el.com>
Cc:	Frédéric Weisbecker <fweisbec@...il.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Li Zefan <lizf@...fujitsu.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Andi Kleen <andi@...stfloor.org>,
	Matt Mackall <mpm@...enic.com>,
	Alexey Dobriyan <adobriyan@...il.com>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>
Subject: Re: [patch] tracing/mm: add page frame snapshot trace


* Wu Fengguang <fengguang.wu@...el.com> wrote:

> Hi Ingo,
> 
> On Sat, May 09, 2009 at 02:27:58PM +0800, Ingo Molnar wrote:
> > 
> > * Wu Fengguang <fengguang.wu@...el.com> wrote:
> > 
> > > > 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.
> > > 
> > > I'd be glad to work with you on the 'object collections' ftrace 
> > > interfaces.  Maybe next month. For now my time have been allocated 
> > > for the hwpoison work, sorry!
> > 
> > No problem - our offer still stands: we are glad to help out with 
> > the instrumentation side bits. We'll even write all the patches for 
> > you, just please help us out with making it maximally useful to 
> > _you_ :-)
> 
> Thank you very much!
> 
> The good fact is, 2/3 of the code and experiences can be reused.
> 
> > Find below a first prototype patch written by Steve yesterday and 
> > tidied up a bit by me today. It can also be tried on latest -tip:
> > 
> >   http://people.redhat.com/mingo/tip.git/README
> > 
> > This patch adds the first version of the 'object collections' 
> > instrumentation facility under /debug/tracing/objects/mm/. It has a 
> > single control so far, a 'number of pages to dump' trigger file:
> > 
> > To dump 1000 pages to the trace buffers, do:
> > 
> >   echo 1000 > /debug/tracing/objects/mm/pages/trigger
> > 
> > To dump all pages to the trace buffers, do:
> > 
> >   echo -1 > /debug/tracing/objects/mm/pages/trigger
> 
> That is not too intuitive, I'm afraid.

This was just a first-level approximation - and it matches the usual 
"0xffffffff means infinite" idiom.

How about changing it from 'trigger' to 'dump_range':

   echo "*" > /debug/tracing/objects/mm/pages/dump_range

being a shortcut for 'dump all'?

And:

   echo "1000 2000" > /debug/tracing/objects/mm/pages/dump_range

?

The '1000' is the offset where the dumping starts, and 2000 is the 
size of the dump.

	Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/