Re: netbsd-5 deadlocks when memory is low

[Emmanuel Dreyfus <manu%netbsd.org@localhost>]

On Fri, Sep 02, 2011 at 12:55:24AM -0400, Mouse wrote:
> That won't fix it; it'll just make it less likely to deadlock.  If
> there is nothing to flush _except_ to the user filesystem that wants
> memory, the system is still wedged.

Sure, but at least it will remove a whole set of deadlocks, where there
are vnode to flush on your root fs, but ioflush remain stuck on flushing
a vnode from a user fs.

> As a scenario less likely to occur, but more likely to deadlock if it
> does occur, consider a system configured with swap to a file that's on
> a userland filesystem, and then let all other swap (if any) fill up.

There are plenty of ways to make a system less able to cope with memory
sortage. I would like to improve the situation for setups where the
administrator made some effort to have a reliable system. For now I 
have to way to avoid deadlocks on netbsd-5.

-- 
Emmanuel Dreyfus
manu%netbsd.org@localhost