Re: [PATCH v6 07/16] x86/mm/64: Disable PMD page mapping of vmemmap

[Oscar Salvador]

On Tue, Nov 24, 2020 at 05:52:50PM +0800, Muchun Song wrote:
> If we enable the CONFIG_HUGETLB_PAGE_FREE_VMEMMAP, we can just
> disbale PMD page mapping of vmemmap to simplify the code. In this
> case, we do not need complex code doing vmemmap page table
> manipulation. This is a way to simply the first version of this
> patch series. In the future, we can add some code doing page table
> manipulation.

IIRC, CONFIG_HUGETLB_PAGE_FREE_VMEMMAP was supposed to be enabled by default,
right?
And we would control whether we __really__ want to this by a boot option,
which was disabled by default?

If you go for populating the memmap with basepages by checking
CONFIG_HUGETLB_PAGE_FREE_VMEMMAP, would not everybody, even the ones that
did not enable this by the boot option be affected?

-- 
Oscar Salvador
SUSE L3