Re: copy on write memory

[urmk@reason.marist.edu]

> It's true, you did mention it before, but I was looking for something 
> else at the time. What I have in mind doesn't require so much 
> configuration. On the other hand it doesn't exist, and this does.

Ah.  I couldn't remember if I'd sent it or not (or if I'd even tried to send
it from an address that was on the list, a few go to the same mailbox at 
the moment)

> But the patch is against quite an old source, and it doesn't compile 
> straight out of the box. Do you know if there are updated patches 
> against 2.6.9?

I can check.

> I get this error (which I haven't yet examined in detail):
> 
>  CC [M]  fs/xip2fs/file.o
> fs/xip2fs/file.c: In function `xip2_do_file_read':
> fs/xip2fs/file.c:69: error: structure has no member named `buf'
> fs/xip2fs/file.c: In function `__xip2_file_aio_read':
> fs/xip2fs/file.c:119: error: structure has no member named `buf'
> fs/xip2fs/file.c: In function `xip2_file_sendfile':
> fs/xip2fs/file.c:302: error: structure has no member named `buf'
> 
> This was against xen-2.0.1 as of today 18 Nov 2004

I highly doubt that it will be directly applicable to xen - the entire backend
mechanism is linked into the z/VM shared memory system between guests.  I was
more pointing it out as a probable jumping off point (most of the work is done,
it just needs to use the xen memory sharing instead) and as a workable
concept for a less-cpu-intensive copy-on-write mechanism.

I'll take a look for a newer patch and see if I can scrape up some time to
apply the backend to xen, but I don't know when I'll get a chance -- don't let
me hold anyone else up who was considering working on it.

-m



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