Commit c367a441 authored Mar 01, 2016 by Aneesh Kumar K.V Committed by Michael Ellerman Mar 03, 2016

powerpc/mm: add _PAGE_HASHPTE similar to 4K hash



We don't need to update linux page table entry with _PAGE_HASHPTE early
in hash pte fault. A parallel pte update will loop via _PAGE_BUSY
and look at _PAGE_HASHPTE for a required hpte flush only if
_PAGE_BUSY is cleared. That ensures a pte update will wait for a
parallel hpte insert to finish before looking at _PAGE_HASHPTE bit.

To avoid further confusion drop setting _PAGE_HASHPTE in cmpxchg in __hash_page_4K.

commit 41743a4e ("powerpc: Free a PTE bit on ppc64 with 64K pages")
did similar change for 64K config

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

parent e9a68147

arch/powerpc/mm/hash64_4k.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -44,7 +44,7 @@ int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
		* a write access. Since this is 4K insert of 64K page size
		* also add _PAGE_COMBO
		*/
		new_pte = old_pte \| _PAGE_BUSY \| _PAGE_ACCESSED \| _PAGE_HASHPTE;
		new_pte = old_pte \| _PAGE_BUSY \| _PAGE_ACCESSED;
		if (access & _PAGE_RW)
		new_pte \|= _PAGE_DIRTY;
		} while (old_pte != __cmpxchg_u64((unsigned long *)ptep,