On Mon, Jun 22, 2009 at 03:59:35PM +0100, Gaby Vanhegan wrote: > On 22 Jun 2009, at 14:58, Thomas Pfaff wrote: > >> On Mon, 22 Jun 2009 12:37:08 +0100 >> Gaby Vanhegan <g...@vanhegan.net> wrote: >>> >>> I have a machine with 4GB RAM and a quad core Xeon processor. Will >>> it >>> be able to see the full 4GB of RAM or will I have to tweak bigmem, >>> either by building a custom kernel (really don't want to do that) or >>> by using config()? >>> >> You can't use config to toggle bigmem. You need to set the bigmem >> variable to 1 in /usr/src/sys/arch/amd64/amd64/machdep.c, then you >> compile and install a new kernel. >> >> http://www.openbsd.org/faq/faq5.html#BldKernel explains how. > > > I'd gathered that from reading one of those threads to the end. I > really wanted to avoid having to build a custom kernel, especially if > the results might not even work. I suppose I was just inquiring about > the status of bigmem in 4.5 and if it is considered "safe" to use yet? >
Consider it unsave. Without iommu (e.g. on Intel Boxes) many devices will be unable to talk to memory > 4GB bad if that is where your data is. With the amd64 gart acting as iommu it is possible to use the memory but as nobody is using it for real now expect some bugs to be hit. -- :wq Claudio
