Messages in this thread | | | Date | Tue, 06 Jul 2004 17:58:04 +0200 | From | Lutz Vieweg <> | Subject | How to find out which pages were copied-on-write? |
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Hi,
in an application that MAP_PRIVATEly mmap()s a file it would be quite helpful for me to find out which pages have been copied-on-write.
I found that mincore() does a similar thing by reporting which pages are currently residing in physical memory, but what I want to know is which pages differ from the original file image on disk.
Can you recommend a way to do that? (does not need to be portable beyond Linux)
Alternatively, it would be sufficient if I could turn a private mapping into a shared one (and possibly do an msync() afterwards if I need to make sure the changes have been written out). Would such a feature need a lot of effort to implement?
Yet another feature that I could use if it were available: A "copy-on-read"-mapping. There, a page would become a private copy of a process once _another_ process wrote data to the corresponding file location. But I suspect that feature could be very hard to implement...
Regards,
Lutz Vieweg
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