On Sat, 28 Apr 2007 21:26:42 +0100 "Bradley Chapman" <[EMAIL PROTECTED]> wrote:
> After installing a second 512MB SODIMM into my laptop, I noticed that > my 2.6.18.3 kernel only detected and used 896MB of the resulting 1GB, > and informed me that I needed to enable high memory in order to access > the remaining 127MB. > > While doing so, I noticed that the help text stated that enabling high > memory (in my case, CONFIG_HIGHMEM4G) should only be done if the > system the kernel is running on has more than 1GB, but less than 4GB - > it said that systems with 1GB should leave it off, which resulted in > an eighth of the installed memory going missing. A bit more research > found a three year old thread on this list where it was stated that > enabling CONFIG_HIGHMEM4G sometimes slows the system down due to > sometimes undesirable changes to the way the kernel sets up the memory > map. > > Basically, all I want to know is whether or not enabling > CONFIG_HIGHMEM4G for a laptop that has exactly 1GB of RAM will result > in any performance degradation. > I would expect the advantages of the additional 128MB to considerably outweigh the cost of turning on CONFIG_HIGHMEM4G. That cost will be a little extra CPU consumption inside the kernel, but the great majority of CPU consumption usually happens in userspace anyway. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
