It is not clear from the code and the documentation which synchronization discipline prevents concurrent accesses to PTE.

For example, OsUnmapL2PTE clears a page table. However, it seems the page table is not protected from parallel accesses. Let us consider the following cases:

Concurrent Access 1
LOS_MemAlloc->OsMemAllocWithCheck->OsMemPoolExpand->OsTryShrinkMemory->OsShrinkInactiveList->OsDeletePageCacheLru->OsPageCacheDel->OsUnmapAllLocked->OsUnmapPageLocked->LOS_ArchMmuUnmap->OsUnmapL2PTE to info->archMmu.

Concurrent Access 2
ShmatVmmAlloc->LOS_MMap->OsUserHeapFree->LOS_ArchMmuUnmap->OsUnmapL2PTE to vmSpace->archMmu.

May these accesses to page table happen concurrently?
May these PTE be the same?