Date: Fri, 10 Apr 2009 11:20:12 -0700 (PDT) From: gahn <ipfreak@yahoo.com> To: Matthew Seaman <m.seaman@infracaninophile.co.uk> Cc: freebsd general questions <freebsd-questions@freebsd.org> Subject: Re: loader.conf Message-ID: <352228.61716.qm@web52106.mail.re2.yahoo.com> In-Reply-To: <49DF6DEC.7010706@infracaninophile.co.uk>
next in thread | previous in thread | raw e-mail | index | archive | help
Thanks for the detailed information. Best --- On Fri, 4/10/09, Matthew Seaman <m.seaman@infracaninophile.co.uk> wrote: > From: Matthew Seaman <m.seaman@infracaninophile.co.uk> > Subject: Re: loader.conf > To: ipfreak@yahoo.com > Cc: "freebsd general questions" <freebsd-questions@freebsd.org> > Date: Friday, April 10, 2009, 9:03 AM > gahn wrote: > > Hi all: > > > > I have a machine with 2GB memory. in the file > loader.conf, there is a line: > > > > #hw.physmem="1G" # Limit > physical memory. See loader(8) > > > > Could I remove the "#" and change that to > "2G"? > > > > Interestingly, the sysctl indicates the parameter of > "hw.physmem" is not changeable. > > > > Any guru here give me some enlightenment? > > hw.physmem is a loader tunable: ie. you can only set it > from the boot > loader before the kernel is fully operational. Once the > kernel is running > it can't be altered. > > hw.physmem is designed to let you test running a kernel > with less RAM > than is physically installed in a machine. Not having to > pop the case > and physically pull memory sticks out can be pretty useful. > It's not of > general interest -- only for kernel and various other > software developers > in the main -- as the usual thing is to make use of all the > RAM you have > available or (in the case of 32bit machines) that the > system is capable of > addressing. > If hw.physmem is unset in loader.conf the kernel will > automatically use all > the memory available to it: this is the correct and > desirable behaviour for > the vast majority of systems. For a 2GB machine, that > means the system will > use all the RAM that's installed. > > Cheers, > > Matthew > > -- Dr Matthew J Seaman MA, D.Phil. 7 > Priory Courtyard > Flat 3 > PGP: http://www.infracaninophile.co.uk/pgpkey Ramsgate > Kent, CT11 > 9PW
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?352228.61716.qm>