Re: 2.4.0-test10-pre3:Oops in mm/filemap.c:filemap_write_pa

[Trond Myklebust]

>>>>> " " == Linus Torvalds <[EMAIL PROTECTED]> writes:


     > The advantage of clearing the uptodate flag (as opposed to
     > doing what we do now - dropping the page altogether) is that
     > there would be no cache aliasing issues, and there would be no
     > issues with a page and its associated data just "disappearing"
     > from under somebody. It would cause the page to be read in
     > again the next time it is faulted in or somebody does a read()
     > on it, and that's exactly what we want.

I've proposed this in the past, but there you refused on the grounds
that it breaks assumptions in the VFS. I'm otherwise happy with this
sort of thing. It ensures both shared mmap() and cache consistency.

The only problem I can think of would be for dirty pages that haven't
yet been msync()ed, however I'm far from being competent to evaluate
any side-effects on the VM.

     > However, we _do_ need to WB the page data some way - but the
     > decision on whether to invalidate write-backs or finish them
     > would have to be up to the low-level filesystem.

This is already in place.

Cheers,
  Trond
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