Re: Can't make use of swap memory in 2.6.7-bk19

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

William Lee Irwin III wrote:
>> Oh, then I'm stuck in the GFP_WIRED quagmire after all. I guess since
>> fixing it involves adding lines I'm in deep trouble.

On Fri, Jul 09, 2004 at 10:57:01AM +1000, Nick Piggin wrote:
> Or just see if you can tighten up the conditions for OOM to
> start with?

You must not have seen the patches. the thread starts with Message-id:
<0406231407.HbLbJbXaHbKbWa5aJb1a4aKb0a3aKb1a0a2aMbMbYa3aLbMb3aJbWaJbXaMbLb1a342@holomorphy.com>

They added a flag indicating wiredness or no to the gfp_mask, which was
then propagated down the call chain and eventually passed as an argument
to out_of_memory(). In turn, out_of_memory() used the flag to determine
whether the nr_swap_pages > 0 check was relevant. i.e. they refined the
OOM conditions based on the wiredness of the failing allocation. What
probably got the stuff permavetoed was the stats reporting I did along
with it that would have been trivial to drop while retaining the needed
functional change. The patch was motivated by the nr_swap_pages > 0
check deadlocking. The __GFP_WIRED business was done to discriminate
the obvious deadlocking scenario from the false OOM mentioned here.

-- wli