Date: Tue, 13 Jan 1998 11:56:31 +1030 From: Mike Smith <mike@smith.net.au> To: Amancio Hasty <hasty@rah.star-gate.com> Cc: Stephen Hocking <shocking@mailbox.uq.edu.au>, multimedia@freebsd.org, hackers@freebsd.org Subject: Re: FreeBSD Quake page Message-ID: <199801130126.LAA04334@word.smith.net.au> In-Reply-To: Your message of "Mon, 12 Jan 1998 10:38:23 -0800." <199801121838.KAA00321@rah.star-gate.com>
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> > syscall 163 is the linux system call mremap which we have not implemented. > > If anyone knows how to implement mremap please let me know. Heh. I finally managed to get a copy of the Linux kernel source where I can look at it. mremap() is more or less what its name suggests; it allows you to modify an existing mapping. u_long mremap(caddr_t addr, u_long old_len, u_long new_len, u_long flags) There are basically two cases. - Shrink a mapping. (new_len < old_len) You can implement this as munmap(addr + new_len, old_len - new_len). - Grow a mapping, moving disallowed. This requires changing map details. I *think* I can see, in principle, how to do this, but it would have to be done in the vm_mmap module rather than in the linuxulator. John, can you comment on this? As a quick hack, you could try implementing the shrink case, and return ENOMEM for the other cases. This *might* work, depending on the consumer. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\
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