On Mon 03-10-16 02:32:48, Christoph Hellwig wrote:
> On Mon, Oct 03, 2016 at 10:15:49AM +0200, Jan Kara wrote:
> > Yeah, so DAX path is special because it installs its own PTE directly from
> > the fault handler which we don't do in any other case (only driver fault
> > handlers commonly do this but those generally don't care about
> > ->page_mkwrite or file mappings for that matter).
> >
> > I don't say there are no simplifications or unifications possible, but I'd
> > prefer to leave them for a bit later once the current churn with ongoing
> > work somewhat settles...
>
> Allright, let's keep it simple for now. Being said this series clearly
> is 4.9 material, but any chance to get a respin of the invalidate_pages
Agreed (actually 4.10).
> series as that might still be 4.8 material?
The problem with invalidate_pages series is that it depends on the ability
to clear the dirty bits in the radix tree of DAX mappings (i.e. the first
series). Otherwise radix tree entries that get once dirty can never be safely
evicted, invalidate_inode_pages2_range() will keep returning EBUSY and
callers get confused (I've tried that few weeks ago).
If I dropped patch 5/6 for 4.9 merge (i.e., we would still happily discard
dirty radix tree entries from invalidate_inode_pages2_range()), things
would run fine, just fsync() may miss to flush caches for some pages. I'm
not sure that's much better than current status quo though. Thoughts?
Honza
--
Jan Kara <[email protected]>
SUSE Labs, CR
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