Messages in this thread | | | Date | Wed, 10 Oct 2012 08:49:05 -0700 | Subject | Re: [PATCH 03/10] x86, mm: get early page table from BRK | From | Yinghai Lu <> |
| |
On Wed, Oct 10, 2012 at 7:17 AM, Konrad Rzeszutek Wilk <konrad@kernel.org> wrote: > On Tue, Oct 09, 2012 at 06:03:33PM -0700, Yinghai Lu wrote:
>> good point, i add one line comment to the revised patch. >> >> +/* need 3 4k for initial PMD_SIZE, 4k for 0-ISA_END_ADDRESS */ > > Can you explain the math please? It sounds like this is based on > the assumption that this you are using huge pages. But what if you > are not? What if you can only do 4KB pages?
yes that is some extreme case: assume that 2M range is [2T-2M, 2T), one page for PGD-[2T-512g, 2T), one for PUD - [2T-1G, 2T), and one for PMD -: [2T-2M, 2T)
| |