x86/mm: Always tell core mm to sync kernel mappings
Core mm code obviously makes changes to a copy of the page tables.
Those changes sometimes need to be synchronized with other copies of
the page tables. But when this needs to happen is highly architecture
and configuration specific.
In cases where kernel PMDs are shared across processes
(SHARED_KERNEL_PMD) the core mm does not itself need to do that
synchronization for kernel PMD changes. The x86 code represents
this by clearing the PGTBL_PMD_MODIFIED bit cleared in those
configs to avoid expensive synchronization.
The kernel is moving toward never sharing kernel PMDs. Prepare for
that and make 32-bit PAE always set PGTBL_PMD_MODIFIED, even if there
is no modification to synchronize. This behavior is temporarily slower
but will be required soon.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
1 file changed
