On Friday, March 04, 2011 12:48:55 pm Andriy Gapon wrote: > 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.
Also, the message buffer for dmesg, and the kernel binary itself. -- John Baldwin _______________________________________________ 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"
