Re: Analyzed/Solved: Booting 2.6.30-rc2-git7 very slow

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

On Wed, 29 Apr 2009 05:51:36 +0200 Mike Galbraith <efault@gmx.de> wrote:

> On Tue, 2009-04-28 at 18:28 -0700, Andrew Morton wrote: 
> > On Fri, 24 Apr 2009 05:45:19 -0700 (PDT) Martin Knoblauch <knobi@knobisoft.de> wrote:
> > 
> > > 
> > > 
> > >  OK, I just found the reason for both intel-ucode and tg3 failures. Apparently between 2.6.28 and 2.6.29 the mount of sysfs has subtely changed from:
> > > 
> > > /sys /sys sysfs rw 0 0
> > > 
> > > to:
> > > 
> > > none /sys sysfs rw,relatime 0 0
> > 
> > I assume that you're referring to the contents of /proc/mounts?
> > 
> > >  The "none" breaks the RHEL-4 provided hotplug script "firmware.agent" when it tries to parse the mount point for "/sys". As a result, the firmware loading is never properly finished and the driver(s) just timeout on the value  in /sys/class/firmware/timeout. Bingo. Simple fix in user-pace possible - cool down Martin :-)
> > > 
> > > Questions remains: was this intentional? It breaks existing userspace and should therefore be considered a regression - right? On the other hand, it will never be a problem for RHEL-4/5 kernels, unless the change in 2.6.29 gets backported. Any ideas?
> > 
> > afaik that was unintentional and was probably a mistake.
> > 
> > I wonder how we did that.
> 
> <paste>
> > [hotplug]# grep sysfs /proc/mounts
> > none /sys sysfs rw,relatime 0 0
> > /sys /sys sysfs rw,relatime 0 0
> 
> ___(I wonder how the heck that is accomplished)
> 

Beats me.  I'm not seeing likely changes in fs/proc/base.c or around
show_mountinfo().  Maybe sysfs broke in an ingenious way.  (hopefully
cc's viro).

Displaying relatime seems a bit pointless too.