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RE: offline elfutils processing committed
- From: "Stone, Joshua I" <joshua dot i dot stone at intel dot com>
- To: "Martin Hunt" <hunt at redhat dot com>, "Frank Ch. Eigler" <fche at redhat dot com>
- Cc: <systemtap at sources dot redhat dot com>
- Date: Mon, 6 Nov 2006 14:15:41 -0800
- Subject: RE: offline elfutils processing committed
On Monday, November 06, 2006 1:18 PM, Martin Hunt wrote:
> The point is damage control. Systemtap allocates too much memory and
> oom killer gets active, the first thing it will kill is staprun and
> that should unload the module (but this seems broken at the moment).
> So we haven't really hurt the system.
The goal is fine, but I don't think this accomplishes it. My
understanding is that __alloc_pages will keep calling OOM until it is
able to satisfy the request -- thus the module is blocked waiting for
memory. The process might end up something like:
stap module: allocate lots of memory
__alloc_pages: Not enough memory -> OOM kill something (staprun)
__alloc_pages: Still not enough memory -> OOM kill other stuff
__alloc_pages: Yay, now we have enough memory!
stap module: got some memory
stap module: Oops, staprun is gone, better exit...
Ouch...
Josh