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    SubjectRe: [PATCH 11/12] vmscan: Write out dirty pages in batch
    On Mon, 14 Jun 2010 21:16:29 -0400 Rik van Riel <> wrote:

    > Would it be hard to add a "please flush this file"
    > way to call the filesystem flushing threads?

    Passing the igrab()bed inode into the flusher threads would fix the
    iput_final() problems, as long as the alloc_pages() caller never blocks
    indefinitely waiting for the work which the flusher threads are doing.

    Otherwise we get (very hard-to-hit) deadlocks where the alloc_pages()
    caller holds VFS locks and is waiting for the flusher threads while all
    the flusher threads are stuck under iput_final() waiting for those VFS

    That's fixable by not using igrab()/iput(). You can use lock_page() to
    pin the address_space. Pass the address of the locked page across to
    the flusher threads so they don't try to lock it a second time, or just
    use trylocking on that writeback path or whatever.

     \ /
      Last update: 2010-06-15 03:49    [W:0.043 / U:145.508 seconds]
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