Date: Mon, 17 Jun 1996 20:24:30 -0700 From: Sean Eric Fagan <sef@kithrup.com> To: hackers@freebsd.org, michaelh@cet.co.jp Subject: Re: vfork cow? Message-ID: <199606180324.UAA04977@kithrup.com>
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>I didn't realize that vfork in 4.4bsd was implemented with copy-on-write >semantics until I read the deamon book. Is it really going to be a >deprecated call kept around for compatibility? vfork() is *not* deprecated! Doing so would break tons o' stuff ;). vfork's main difference from fork() is that the parent is waits for the child to exec or exit. SysVrX (X < 4) systems that didn't have vfork had to do all sorts of fun things to synchronize; using vfork() makes the code *much* simpler. Keith or Kirk mentioned, at one point, possibly going back to the old semantics; this is useful for large-memory processes, depending on the implementation. (John and David just did some work to improve pmap_copy, which helps address this issue. However, let's get a few processes with 2GBytes of address space active, and see how well it does ;).) Sean.
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