Messages in this thread | | | Date | Wed, 6 May 2009 00:55:34 -0700 (PDT) | From | Martin Knoblauch <> | Subject | Re: Analyzed/Solved: Booting 2.6.30-rc2-git7 very slow |
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----- Original Message ----
> From: Mike Galbraith <efault@gmx.de> > To: Andrew Morton <akpm@linux-foundation.org> > Cc: viro@ZenIV.linux.org.uk; knobi@knobisoft.de; rjw@sisk.pl; linux-kernel@vger.kernel.org; tigran@aivazian.fsnet.co.uk > Sent: Wednesday, May 6, 2009 6:45:40 AM > Subject: Re: Analyzed/Solved: Booting 2.6.30-rc2-git7 very slow > > On Tue, 2009-05-05 at 15:49 -0700, Andrew Morton wrote: > > On Wed, 29 Apr 2009 16:18:45 +0200 > > Mike Galbraith wrote: > > > > > On Wed, 2009-04-29 at 13:08 +0100, Al Viro wrote: > > > > On Wed, Apr 29, 2009 at 01:17:55AM -0700, Andrew Morton wrote: > > > > > > > > > > > > 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. > > > > > > > > > > > > > > > > > > > [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). > > > > > > > > Er... Somebody mounting sysfs twice? From some init script and from > > > > /etc/fstab, perhaps? That definitely looks like two mount(2) had to > > > > have been done to cause that... > > > > > > Yeah, but how does one go about doing that? > > > > > > Using mount -f, I can convince mount to succeed, but I still have only > > > one entry in /proc/mounts, despite what my mount binary imagines. > > > > > > marge:..sys/vm # grep sysfs /proc/mounts > > > sysfs /sys sysfs rw,relatime 0 0 > > > > > > marge:..sys/vm # mount|grep sysfs > > > sysfs on /sys type sysfs (rw) > > > sys on /sys type sysfs (rw) > > > /sys on /sys type sysfs (rw) > > > > > > > So /proc/mounts is OK and /etc/mtab is wrong? > > > > Obvious next step is to strace `mount -f', see what's happening around > > sys_mount(), please. > > Well, there is no syscall with -f. > > I was trying various mount options to see if I could find a way to > create bogons that could confuse scripts. I could create bogons > in /etc/mtab with -f, or bogons in /proc/mounts by using --move. I > could re-create the exact reported data with a combination of mount -n > and mount --move. I could not get a double /proc/mounts entry without > --move, and that seems unlikely to appear in boot scripts. So I still > wonder how the heck it was accomplished. > > I also now wonder why you can --move mounts on top of one another, but > beck with it, ignorance conserves braincells I may some day need :) >
just to bring this back to my problem :-) Last week I reported that the "new" sysfs entry in /proc/mounts already comes out of initrd. Does this ring a bell?
http://lkml.indiana.edu/hypermail/linux/kernel/0904.3/03048.html
Cheers Martin
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