Hi David,
On 2024/8/5 22:43, David Hildenbrand wrote:
On 05.08.24 14:55, Qi Zheng wrote:
Make pte_offset_map_nolock() return pmdval so that we can recheck the
*pmd once the lock is taken. This is a preparation for freeing empty
PTE pages, no functional changes are expected.
Skimming the patches, only patch #4 updates one of the callsites
(collapse_pte_mapped_thp).
In addition, retract_page_tables() and reclaim_pgtables_pmd_entry()
also used the pmdval returned by pte_offset_map_nolock().
Wouldn't we have to recheck if the PMD val changed in more cases after
taking the PTL?
If not, would it make sense to have a separate function that returns the
pmdval and we won't have to update each and every callsite?
pte_offset_map_nolock() had already obtained the pmdval previously, just
hadn't returned it. And updating those callsite is simple, so I think
there may not be a need to add a separate function.
Thanks,
Qi
