Hi Peter, On Wed, Apr 7, 2010 at 1:14 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote: > On 04/06/2010 12:20 PM, Frank Hu wrote: >>> >>> The ELF ABI specifies that user space has 3 GB available to it. That >>> leaves 1 GB for the kernel. The kernel, by default, uses 128 MB for I/O >>> mapping, vmalloc, and kmap support, which leaves 896 MB for LOWMEM. >>> >>> All of these boundaries are configurable; with PAE enabled the user >>> space boundary has to be on a 1 GB boundary. >>> >> >> the VM split is also configurable when building the kernel (for 32-bit >> processors). > > I did say "all these boundaries are configurable". Rather explicitly. > I thought the 896 MB was a hardware limitation on 32 bit architectures and something that cannot be configured? Or am I missing something here? Also the vm-splits refer to "virtual memory" . While ZONE_* and the 896MB we were discussing refers to "physical memory". How then is discussing about vm splits pertinent here? Thanks, -Joel -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
