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Re: Ext2 superblock fault
From: |
Samuel Thibault |
Subject: |
Re: Ext2 superblock fault |
Date: |
Mon, 10 Mar 2008 10:49:21 +0000 |
User-agent: |
Mutt/1.5.12-2006-07-14 |
Thomas Bushnell BSG, le Sun 09 Mar 2008 22:17:05 -0400, a écrit :
> On Mon, 2008-03-10 at 01:19 +0000, Samuel Thibault wrote:
> > This thread is syncing everything, i.e. asking a lot of writes, which
> > triggers the creation of a lot of threads. Unfortunately the superblock
> > was paged out, so they all block on reading it. Unfortunately, since in
> > Debian there is a patch which limits the number of created threads,
> > the read of the superblock doesn't actually create a new thread, that is
> > delayed. But since none of the existing threads can progress (since
> > they are all waiting for the super block), things are just dead
> > locked...
>
> As a general rule, the Hurd always assumes that an RPC can be handled;
> this is quite emebedded in the way diskfs works.
>
> A patch which limits the number of threads is inherently buggy in the
> Hurd, and that patch MUST be disabled for anything to work properly.
Well, there is still a limit in the number of threads in the kernel
itself: THREAD_MAX...
Yes, that should too be dynamically expandable...
> > I'm currently using a quite ugly patch (on top of the >2GB patch) to
> > avoid this by just always keeping a copy of the superblock, attached.
> > I'll commit it in the Debian package.
>
> This is not a fix. This just postpones the problem.
It makes it much less frequent, which is good for the Debian buildd for
instance.
Samuel
- Ext2 superblock fault, Samuel Thibault, 2008/03/01
- Re: Ext2 superblock fault, Samuel Thibault, 2008/03/02
- Re: Ext2 superblock fault, Samuel Thibault, 2008/03/09
- Re: Ext2 superblock fault, Thomas Bushnell BSG, 2008/03/09
- Re: Ext2 superblock fault,
Samuel Thibault <=
- Thread model (was: Ext2 superblock fault), olafBuddenhagen, 2008/03/11
- Re: Thread model, Neal H. Walfield, 2008/03/11
- Re: Thread model, Marcus Brinkmann, 2008/03/12
- Re: Thread model, olafBuddenhagen, 2008/03/17
- Re: Thread model, Neal H. Walfield, 2008/03/17
- Re: Thread model, olafBuddenhagen, 2008/03/18
- Re: Thread model, Thomas Bushnell BSG, 2008/03/12
- Re: Thread model, Neal H. Walfield, 2008/03/12
- Re: Thread model, Thomas Bushnell BSG, 2008/03/12
- Re: Thread model, olafBuddenhagen, 2008/03/17