Re: 2.6.26-rc5-mm2

Nick Piggin
2008-06-11T23:58:57Z

On Thursday 12 June 2008 04:09, Rik van Riel wrote:
> On Tue, 10 Jun 2008 18:48:21 +1000
>
> Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> > > > The tmpfs PageSwapBacked stuff seems rather broken. For
> > > > them write_begin/write_end path, it is filemap.c, not shmem.c,
> > > > which allocates the page, so its no wonder it goes bug. Will
> > > > try to do more testing without shmem.
>
> Fun, so what does shmem_alloc_page do?
>
> > > rikstuff. Could be that the merge caused a problem?
> >
> > Doesn't look like it, but I hadn't followed the changes too closely:
> > rather they just need to test loopback over tmpfs.
>
> Does loopback over tmpfs use a different allocation path?

I'm sorry, hmm I didn't look closely enough and forgot that
write_begin/write_end requires the callee to allocate the page
as well, and that Hugh had nicely unified most of that.

So maybe it's not that. It's pretty easy to hit I found with
ext2 mounted over loopback on a tmpfs file.

> > Is the plan to merge all reclaim changes in a big hit, rather than
> > slowly trickle in the different independent changes?
>
> My original plan was to merge them incrementally, but Andrew is
> right that we should give the whole set as much testing as
> possible.
>
> I have done all the cleanups Andrew asked and fixed the bugs
> that I found after that merge/cleanup. Your bug is the one
> I still need to fix before giving Andrew a whole new set of
> split LRU patches to merge.
>
> (afterwards, I will go incremental fixes only - the cleanups
> he asked for were just too big to do as incrementals)

OK.