Re: [PATCH 2/2] vmevent: Implement greater-than attribute andone-shot mode

From: Anton Vorontsov
Date: Wed Apr 18 2012 - 18:47:58 EST

On Wed, Apr 18, 2012 at 11:01:02PM +0300, Pekka Enberg wrote:
> On Wed, 18 Apr 2012, Anton Vorontsov wrote:
> > This patch implements a new event type, it will trigger whenever a
> > value becomes greater than user-specified threshold, it complements
> > the 'less-then' trigger type.
> >
> > Also, let's implement the one-shot mode for the events, when set,
> > userspace will only receive one notification per crossing the
> > boundaries.
> >
> > Now when both LT and GT are set on the same level, the event type
> > works as a cross event type: it triggers whenever a value crosses
> > the threshold from a lesser values side to a greater values side,
> > and vice versa.
> >
> > We use the event types in an userspace low-memory killer: we get a
> > notification when memory becomes low, so we start freeing memory by
> > killing unneeded processes, and we get notification when memory hits
> > the threshold from another side, so we know that we freed enough of
> > memory.
> >
> > Signed-off-by: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx>
> Did you try vmevent-test with this patch? I'm seeing this:

Yep, with CONFIG_SWAP=n, and I had to a modify the test
since I saw the same thing, I believe. I'll try w/ the swap enabled,
and see how it goes. I think the vmevent-test.c needs some improvemnts
in general, but meanwhile...

> Physical pages: 109858
> read failed: Invalid argument

Can you send me the .config file that you used? Might be that
you have CONFIG_SWAP=n too?


Anton Vorontsov
Email: cbouatmailru@xxxxxxxxx
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