Re: [Bugme-new] [Bug 11323] New: /proc/diskstats does not contain all disk devices

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 13 Aug 2008 16:51:12 -0700
Greg KH <greg@kroah.com> wrote:

> On Wed, Aug 13, 2008 at 01:01:58PM -0700, Andrew Morton wrote:
> > > Problem Description: /proc/diskstats does not contain all the block devices it
> > > should. /sys/block has all the devices, but /proc/diskstats does not.
> > > 
> > > Steps to reproduce: boot a system with >9 (10?) disk devices (24 block
> > > devices?)
> > 
> > The below would be a prime suspect.
> > 
> > Unfortunately a simple revert results in an uncompilable kernel.
> > 
> > 
> > (It drives me up the wall and across the ceiling how the patch has a
> > commit "date" of three months prior to the 2.6.26 release, however it
> > wasn't present in 2.6.26.  What a dumb feature.  How do I make it stop
> > doing this?  gitk kind of gets it right, but isn't useful across DSL)
> 
> $ git show --pretty=fuller 27f302519148f311307637d4c9a6d0fd87d07e4c

<writes a script>

> commit 27f302519148f311307637d4c9a6d0fd87d07e4c
> Author:     Greg Kroah-Hartman <gregkh@suse.de>
> AuthorDate: Thu May 22 17:21:08 2008 -0400
> Commit:     Greg Kroah-Hartman <gregkh@suse.de>
> CommitDate: Mon Jul 21 21:54:49 2008 -0700
> 
> There is a commit date, and the date the patch was written.  Both are
> preserved in git.
> 
> And even if it was committed to a branch before 2.6.26 was released, and
> then pulled in, that's fine, it's distributed development :)

It's useless.  I have never ever ever ever wanted to know when random
person X committed a patch to some local tree.  The overwhelmingly most
common question is "when did that go into Linux".  Sigh.

> $ git describe --contains 27f302519148f311307637d4c9a6d0fd87d07e4c
> v2.6.27-rc1~866^2~40
> 
> showing it first showed up on 2.6.27-rc1.

Spose that works.  My usual recourse is searching the commits list,
which has useful-to-humans ordering information.

Is the date at which it went into mainline recorded?

> Anyway, I don't have any systems with such a large number of devices to
> test with.

I suppose that partitioning a junk disk with lots of little partitions
will show it.  parted wants to go stupid on me though.

>  Running git-bisect should narrow the problem down, you can't
> just revert this patch as later-on patches relied on it, as you found
> out...
> 
> Also, what is the output of these files, what exactly is missing?