Re: PAE and PSE ??

Rafael J. Wysocki
2006-10-22T10:16:15Z

Hi,

On Sunday, 22 October 2006 08:29, Sandeep Kumar wrote:
> Hi all,
> I have read in UTLK by bovet that the linux kernel does not uses the
> PSE bit on an x86
> machine. Then how come we have the hugetlbfs, which provides support
> for 4MB pages ?

AFAIK, PSE is only used when PAE is not set and then it enables the 4 MB
pages. If PAE is set, the 4 MB pages are impossible because there are only
512 entries per page table, but 2 MB pages can be used instead (and you don't
need to set PSE to use them).

Greetings,