Re: Race between vmtruncate and mapped areas?

[Andrea Arcangeli <andrea@suse.de>]

On Thu, May 15, 2003 at 02:20:00AM -0700, Andrew Morton wrote:
> Andrea Arcangeli <andrea@suse.de> wrote:
> >
> > and it's still racy
> 
> damn, and it just booted ;)
> 
> I'm just a little bit concerned over the ever-expanding inode.  Do you
> think the dual sequence numbers can be replaced by a single generation
> counter?

yes, I wrote it as a single counter first, but was unreadable and it had
more branches, so I added the other sequence number to make it cleaner.
I don't mind another 4 bytes, that cacheline should be hot anyways.

> I do think that we should push the revalidate operation over into the vm_ops. 
> That'll require an extra arg to ->nopage, but it has a spare one anyway (!).

not sure why you need a callback, the lowlevel if needed can serialize
using the same locking in the address space that vmtruncate uses. I
would wait a real case need before adding a callback.

Andrea