On 18 Jul 2002, Robert Love wrote:

On Thu, 2002-07-18 at 09:36, Szakacsits Szabolcs wrote:

quoted

This is what I would do first [make sure you don't hit any resource,
malloc, kernel memory mapping, etc limits -- this is a simulation that
must eat all available memory continually]:
main(){void *x;while(1)if(x=malloc(4096))memset(x,666,4096);}

When the above used up all the memory try to ssh/login to the box as
root and clean up the mess. Can you do it?

- with strict overcommit and the "allocations must meet backing store"
rule (policy #3) the above can never use all physical memory

So you can't do it: if this user can't get more memory neither root.

- if your point is that a rogue user can use all of the systems memory,
then you need per-user resource accounting.

I explicitely mentioned above, "make sure you don't hit any resource
... limit".

- the point of this patch is to not use MORE memory than the system
has.

I had my [not finished] own non-overcommit patch based on Eduardo
Horvath's from 2000, no need to explain what it means :) Actually the
basics of your patch looks very similar to Eduardo's one.

I say nothing else except that I am trying to avoid OOM and push
the allocation failures into the allocations themselves.  Assuming the
accounting is correct (and it seems to be) then Alan and I have
succeeded.

And my point (you asked for comments) was that, this is only (the
harder) part of the solution making Linux a more reliable (no OOM
killing *and* root always has the control) and cost effective platform
(no need for occasionally very complex and continuous resource limit
setup/adjusting, especially for inexpert home/etc users).

	Szaka

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