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    SubjectRe: [PATCH 3/3] mlock: avoid dirtying pages and triggering writeback
    On Wed, 17 Nov 2010 18:52:30 -0500
    "Ted Ts'o" <> wrote:

    > On Thu, Nov 18, 2010 at 10:11:43AM +1100, Dave Chinner wrote:
    > > I don't think ->page_mkwrite can be worked around - we need that to
    > > be called on the first write fault of any mmap()d page to ensure it
    > > is set up correctly for writeback. If we don't get write faults
    > > after the page is mlock()d, then we need the ->page_mkwrite() call
    > > during the mlock() call.
    > OK, so I'm not an mm hacker, so maybe I'm missing something. Could
    > part of this be fixed by simply sending the write faults for
    > mlock()'ed pages, so page_mkwrite() gets called when the page is
    > dirtied. Seems like a real waste to have the file system pre-allocate
    > all of the blocks for a mlock()'ed region. Why does mlock() have to
    > result in the write faults getting suppressed when the page is
    > actually dirtied?

    Yup, I don't think it would be too bad to take a minor fault each time
    an mlocked page transitions from clean->dirty.

    In fact we should already be doing that, after the mlocked page gets
    written back by kupdate? Hope so!

     \ /
      Last update: 2010-11-18 01:55    [W:0.025 / U:11.916 seconds]
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