Messages in this thread | | | Date | Thu, 21 Oct 2004 17:15:58 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] zap_pte_range should not mark non-uptodate pages dirty |
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Andrew Morton <akpm@osdl.org> wrote: > > I don't get it. invalidate has the pageframe. All it need to do is to > lock the page, examine mapcount and if it's non-zero, do the shootdown.
unmap_mapping_range() will do that - can call it one page at a time, or batch up runs of pages. It's not fast, but presumably not frequent either.
The bigger problem is shooting down the buffer_heads. It's certainly the case that mpage_readpage() will call block_read_full_page() which will then bring the page uptodate without performing any I/O.
And invalidating the buffer_heads in invalidate_inode_pages2() is tricky - we need to enter the filesystem and I'm not sure that either ->invalidatepage() or ->releasepage() are quite suitable. For a start, they're best-effort and may fail. If we just go and mark the buffers not uptodate we'll probably give ext3 a heart attack, so careful work would be needed there.
Let's go back to why we needed all of this. Was it just for the NFS something-changed-on-the-server code? If so, would it be sufficient to add a new invalidate_inode_pages3() just for NFS, which clears the uptodate bit? Or something along those lines?
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