Re: [linux-usb-devel] khubd and ent:sda1 sucking CPU with reiser4+ USB HD

[Alan Stern]

On Wed, 7 Mar 2007, Pete Zaitcev wrote:

> On Wed, 7 Mar 2007 17:18:29 -0500 (EST), Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> 
> > I've never heard of a process failing to show up in a SysRq-t listing.  It 
> > suggests something is wrong with the process management in the kernel you 
> > were using.  That leads me to think a non -mm kernel might give more 
> > informative results.
> 
> I think, if a process is looping, it's not shown in SysRq-t. So maybe
> khubd is on a CPU.

You mean, if it is currently running?  I don't believe that.  A simple 
test comparison shows every process listed in "ps -A" also listed in 
SysRq-t.

> In RHEL we have a patch for SysRq-w, which showed all CPU states by
> the way of a special IPI (unless looping with closed interrups, of course).
> But this capability seems a bit degraded in stock SysRq-w. It might not
> catch this (does not seem for me in 2.6.20).
> 
> Another possibility is, something killed khubd. It's only a process
> after all. Remember how we had grief with it being killed by "telinit 1".

If it was killed then it wouldn't show up in "ps" or as a directory under 
/proc.

Alan Stern

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