Messages in this thread | | | Date | Tue, 16 Jan 2001 13:47:37 +0100 | From | Felix von Leitner <> | Subject | Re: Is sendfile all that sexy? |
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Thus spake Ingo Molnar (mingo@elte.hu): > > I don't know how Linux does it, but returning the first free file > > descriptor can be implemented as O(1) operation. > to put it more accurately: the requirement is to be able to open(), use > and close() an unlimited number of file descriptors with O(1) overhead, > under any allocation pattern, with only RAM limiting the number of files. > Both of my proposals attempt to provide this. It's possible to open() O(1) > but do a O(log(N)) close(), but that is of no practical value IMO.
I cheated. I was only talking about open(). close() is of course more expensive then.
Other than that: where does the requirement come from? Can't we just use a free list where we prepend closed fds and always use the first one on open()? That would even increase spatial locality and be good for the CPU caches.
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