Messages in this thread | | | Date | Sun, 24 Mar 1996 19:59:38 +0200 (EET) | From | Linus Torvalds <> | Subject | Re: mremap() proposal (was Re: malloc and joe) |
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On Sun, 24 Mar 1996, Snow Cat wrote: > > If the mapping grows, what is the content of new pages? Is it always > MAP_ANON or new sections of the same file that was used for mapping?
Conceptually, mremap() really only extends/shrinks the memory mapping, so the new pages will be an extension of whatever the old mmap was. In most cases (at least for the malloc case) this will be a anonymous mapping, but it's by no means an error to extend any mapping you have created.
Extending a file mapping could potentially be useful if you want to track a file when it grows, for example. You'd just do something like
addr = mmap(... st.st_size ...)
for the initial mapping, and then when the process notices that the file has grown (or shrunk), it does a
mremap(addr, old_size, st.st_size)
to be able to read the new pages. A very logical interface, in fact.
Linus
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