Date: Wed, 22 Oct 2003 09:40:44 -0500 From: Dan Nelson <dnelson@allantgroup.com> To: Q <q_dolan@yahoo.com.au> Cc: Kris Kennaway <kris@obsecurity.org> Subject: Re: Some mmap observations compared to Linux 2.6/OpenBSD Message-ID: <20031022144043.GI55642@dan.emsphone.com> In-Reply-To: <1066820436.25609.93.camel@boxster.onthenet.com.au> References: <1066789354.21430.39.camel@boxster.onthenet.com.au> <20031022082953.GA69506@rot13.obsecurity.org> <1066816287.25609.34.camel@boxster.onthenet.com.au> <20031022095754.GA70026@rot13.obsecurity.org> <1066820436.25609.93.camel@boxster.onthenet.com.au>
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In the last episode (Oct 22), Q said: > Yes, it would appear this is a legacy thing that existed in the > original 1994 import of the BSD 4.4 Lite source. Both FreeBSD and > NetBSD still use this technique, but OpenBSD changed to using > Red-Black trees back in Feb 2002. > > The actual commit quote reads: > > "use a red-black tree to find entries in the vm_map. augment the > red-black tree to find free space between entries. speeds up memory > allocation, etc..." > > I am wondering if there is a compelling reason why the technique used > by OpenBSD could not be adapted to FreeBSD's VM system. Probably just a case of "too much to do and not enough people to do it". FreeBSD already has sys/tree.h, which provides the red-black tree macros. -- Dan Nelson dnelson@allantgroup.com
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