Re: mmap-related questions

Kenny Simpson
2003-04-02T03:07:18Z

--- Benjamin LaHaise <bcrl@redhat.com> wrote:
> the act of unmapping them transfers the
> dirty bit from the page
> tables into the page cache where fsync() acts on
> them.
>
Should this info be included with Mel Gorman's
excellent doc:
http://www.csn.ul.ie/~mel/projects/vm/guide/html/understand/node31.html#SECTION009411000000000000000
Or is it there, but I missed it?

> The
> one case this breaks down
> on is when the mmap()'d file is on NFS -- the
> reordering there can result in
> writebacks from mmap()s occuring in unexpected ways.
I sometimes wish mmap was not supported on NFS, or at
least require a special MAP_NFS flag be used. It has
caused lots of pain over the years.

Thanks again for this info, it has helped greatly!

-Kenny

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