Re: [PATCH 2/2] mm/thp: Rename pmd_mknotpresent() as pmd_mknotvalid()

[Will Deacon]

On Fri, Mar 20, 2020 at 10:24:17AM +0530, Anshuman Khandual wrote:
> pmd_present() is expected to test positive after pmdp_mknotpresent() as the
> PMD entry still points to a valid huge page in memory. pmdp_mknotpresent()
> implies that given PMD entry is just invalidated from MMU perspective while
> still holding on to pmd_page() referred valid huge page thus also clearing
> pmd_present() test. This creates the following situation which is counter
> intuitive.
> 
> [pmd_present(pmd_mknotpresent(pmd)) = true]
> 
> This renames pmd_mknotpresent() as pmd_mknotvalid() reflecting the helper's
> functionality more accurately while changing the above mentioned situation
> as follows. This does not create any functional change.
> 
> [pmd_present(pmd_mknotvalid(pmd)) = true]
> 
> This is not applicable for platforms that define own pmdp_invalidate() via
> __HAVE_ARCH_PMDP_INVALIDATE. Suggestion for renaming came during a previous
> discussion here.

Bikeshed alert: maybe pmd_mkinvalid() would be better, given that this is
a one-trick pony for pmdp_invalidate()?

Will