Re: [discuss] Re: 32-bit dma allocations on 64-bit platforms

[William Lee Irwin III <wli@holomorphy.com>]

On Fri, Jun 25, 2004 at 01:21:57AM +0200, Andrea Arcangeli wrote:
> what you have to do is this:
> 1) swapoff -a (it must not fail!! it cannot fail if you run it first)
> 2) fill 130000K in pagecache, be very careful, not more than that, every
>    mbyte matters
> 3) run your program and allocate 904000K!!! (not 512M!!!)
> then keep using the machine until it lockups because it cannot reloate
> the anonymous memory from the 900M of lowmem to the 130M of highmem.
> But really I said you need >=2G to have a realistic chance of seeing it.
> So don't be alarmed you cannot reproduce on a 1G box by allocating 512M
> and with swap still enabled, you had none of the conditions that make it
> reproducible.
> I reproduced this dozen of times so I know how to reproduce it very
> well (amittedly not in 2.6 because nobody crashed on this yet).

This resembles the more sophisticated testcase I originally had in mind.
I'll be out for a couple of hours and then I'll fix this up.


-- wli