Re: [PATCH] [13/16] HWPOISON: The high level memory error handler in the VM v3

Andi Kleen
2009-05-28T10:44:30Z

On Thu, May 28, 2009 at 06:33:00PM +0800, Wu Fengguang wrote:
> > > > You haven't waited on writeback here AFAIKS, and have you
> > > > *really* verified it is safe to call delete_from_swap_cache?
> > >
> > > Good catch. I'll soon submit patches for handling the under
> > > read/write IO pages. In this patchset they are simply ignored.
> >
> > Yes, we assume the IO device does something sensible with the poisoned
> > cache lines and aborts. Later we can likely abort IO requests in a early
> > stage on the Linux, but that's more advanced.
> >
> > The question is if we need to wait on writeback for correctness?
>
> Not necessary. Because I'm going to add a me_writeback() handler.

Ok but without it. Let's assume me_writeback() is in the future.

I'm mainly interested in correctness (as in not crashing) of this
version now.

Also writeback seems to be only used by nfs/afs/nilfs2, not in
the normal case, unless I'm misreading the code.

The nilfs2 case seems weird, I haven't completely read that.

> Then the writeback pages simply won't reach here. And it won't
> magically go into writeback state, since the page has been locked.

But since we take the page lock they should not be in writeback anyways,
no?

-Andi

--
ak@linux.intel.com -- Speaking for myself only.