Re: [RFC][PATCH 2/9] deadlock prevention core

Philip R. Auld
2006-08-21T13:27:17Z

Hi Andrew,

Rumor has it that on Fri, Aug 18, 2006 at 07:44:35PM -0700 Andrew Morton said:
> On Fri, 18 Aug 2006 16:44:01 -0700
> Daniel Phillips <phillips@google.com> wrote:
>
> - We expect that the lots-of-dirty-anon-memory-over-swap-over-network
> scenario might still cause deadlocks.
>
> I assert that this can be solved by putting swap on local disks. Peter
> asserts that this isn't acceptable due to disk unreliability. I point
> out that local disk reliability can be increased via MD, all goes quiet.

Putting swap on local disks really messes up the concept of stateless
servers. I suppose you can do some sort of swap encryption, but
otherwise you need to scrub the swap partition on boot if you
re-purpose the hardware. You also then need to do hardware
configuration to make sure the local disks are all setup the
same way across all server platforms so the common images can
boot.

Please don't require a hardware solution to a software problem.

>
> A good exposition which helps us to understand whether and why a
> significant proportion of the target user base still wishes to do
> swap-over-network would be useful.
>

I can't claim to represent a significant proportion of the target
user base. However, stateless hardware is a powerful and useful
model.

Cheers,

Phil

--
Philip R. Auld, Ph.D. Egenera, Inc.
Software Architect 165 Forest St.
(508) 858-2628 Marlboro, MA 01752