From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pat LaVarre <p.lavarre@ieee.org>
Subject: favourite vfs globals
Date: 28 Nov 2003 14:05:31 -0700
Sender: linux-fsdevel-owner@vger.kernel.org
Message-ID: <1070053531.2340.40.camel@patrh9>
Mime-Version: 1.0
Content-Type: text/plain
Content-Transfer-Encoding: 7bit
Return-path: <linux-fsdevel-owner@vger.kernel.org>
Received: from email-out2.iomega.com ([147.178.1.83]:17608 "EHLO
	email.iomega.com") by vger.kernel.org with ESMTP id S263472AbTK1VGA
	(ORCPT <rfc822;linux-fsdevel@vger.kernel.org>);
	Fri, 28 Nov 2003 16:06:00 -0500
Received: from royntex01.iomegacorp.com (unknown [147.178.90.120])
	by email.iomega.com (Postfix) with ESMTP id 1C29720A8
	for <linux-fsdevel@vger.kernel.org>; Fri, 28 Nov 2003 14:06:00 -0700 (MST)
To: linux-fsdevel@vger.kernel.org
List-Id: linux-fsdevel.vger.kernel.org

Which vfs globals are the most fun, in lk like 2.6.0-test11?

Pat LaVarre

P.S. I ask because:

> From: http://marc.theaimsgroup.com/?l=linux-fsdevel&m=107004461717172
> Subject:  Re: zeroes read back more often than appended
> Date:     2003-11-28 18:29:39
>
> CONFIG_DEBUG_KERNEL=y
> CONFIG_DEBUG_INFO=y
> CONFIG_DEBUG_SLAB=y
> CONFIG_MAGIC_SYSRQ=y

gdb vmlinux /proc/kcore

indeed does let me print globals that make some kind of sense. 
Specifically on my own in stunning ignorance, I notice Six things:

1) `?` suggests `help`.

2) `help` suggests `info variables`.

3) `info variables` takes minutes to complete, but writes its list out
thru tee if first you thought to tee your sudo'ed gdb.

4) `info variables vfs` completes much more quickly.

5) `print xtime` returns the same result til you `quit` and re-enter
gdb, also that result appears in between what `date +'%s %N'` prints
before and after, suggesting that this approach to gdb takes a blurry
snapshot of kernel memory and then walks us thru a stale copy of all the
bits.

6) Substituting /dev/kmem for /proc/kcore prints zero for xtime,
suggesting sym table addresses somehow not sync'ed with physical memory
in that abuse.