Subject: Re: [ckrm-tech] RFC: Memory Controller
From: Dave Hansen <haveblue@us.ibm.com>
To: Pavel Emelianov <xemul@openvz.org>
Cc: balbir@in.ibm.com, vatsa@in.ibm.com, dev@openvz.org, sekharan@us.ibm.com,
       ckrm-tech@lists.sourceforge.net, linux-kernel@vger.kernel.org,
       pj@sgi.com, matthltc@us.ibm.com, dipankar@in.ibm.com,
       rohitseth@google.com, menage@google.com
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Date: Tue, 31 Oct 2006 09:04:08 -0800
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On Tue, 2006-10-31 at 11:48 +0300, Pavel Emelianov wrote:
> If memory is considered to be unreclaimable then actions should be
> taken at mmap() time, not later! Rejecting mmap() is the only way to
> limit user in unreclaimable memory consumption.

I don't think this is necessarily true.  Today, if a kernel exceeds its
allocation limits (runs out of memory) it gets killed.  Doing the
limiting at mmap() time instead of fault time will keep a sparse memory
applications from even being able to run.

Now, failing an mmap() is a wee bit more graceful than a SIGBUS, but it
certainly introduces its own set of problems.

-- Dave

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