on 04/03/2011 16:36 Dmitry Krivenok said the following: > Hello Hackers, > I've limited the amount of physical memory visible for my FreeBSD-8.2 by > adding > the following in loader.conf: > > $ cat /boot/loader.conf | grep hw.physmem > hw.physmem="500M" > $ > > However, according to sysctl, the system sees > > $ sysctl hw.physmem > hw.physmem: 507445248 > $ > > The difference is (500 * 2**20 - 507445248) / 2**20 == 16.0625 Mb. > How does the system use this "hidden" memory?
Some memory is taken by structures that describe usable pages. There is one vm_page_t structure per each 4KB page. I believe that that memory is excluded from physmem. -- Andriy Gapon _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
