Subject: Re: momentary freezes in -current
To: NetBSD Users Discussion List <>
From: Greg A. Woods <>
List: current-users
Date: 07/26/2006 14:41:55
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At Wed, 26 Jul 2006 07:33:27 +1000,
Daniel Carosone wrote:
> This is the same issue Thor described just a few days ago in response
> to another question on, I think, tech-kern.
> Softdep is generating a huge flood of metadata writes, many more than
> the disk subsystem can process, and ~everything gets jammed waiting
> for those to clear.  Processes blocking directly on the disk get
> starved, and other processes can get stuck on the vnode lock for the
> root of the filesystem.
> It's not hung, though it can seem that way especially if you're
> running X and the Xserver is one of the processes that gets stuck.

That reminds me....  assuming the Xserver process doesn't have any pages
out on disk, maybe there should be an option on disk-full workstations
to handle mouse interrupts at the same priority level as disk interrupts
(if they're not already) so that the user won't perceive such apparent
hangs quite so easily.  I.e. at least they'll be able to move the mouse
cursor around, even if doing so continuously and quickly could slow down
the disk throughput, and even if clicking on things doesn't always have
any immediate effect, though perhaps if the window manager is ready to
run then at least it'll be able to show a menu, etc. too.

(of course this is where "having enough memory" comes into play so that
one's Xserver process and window manager, xclock, etc. don't have to
fight with the disk cache just to give a perception of decent
interactive response)

						Greg A. Woods

H:+1 416 218-0098 W:+1 416 489-5852 x122 VE3TCP RoboHack <>
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