powerpc/64s/radix: prefetch user address in update_mmu_cache

Prefetch the faulting address in update_mmu_cache to give the page
table walker perhaps 100 cycles head start as locks are dropped and
the interrupt completed.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin 2018-06-01 20:01:18 +10:00 committed by Michael Ellerman
parent f569bd94ef
commit 68662f85f3
2 changed files with 5 additions and 2 deletions

View File

@ -509,8 +509,10 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
*/
unsigned long access, trap;
if (radix_enabled())
if (radix_enabled()) {
prefetch((void *)address);
return;
}
/* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
if (!pte_young(*ptep) || address >= TASK_SIZE)

View File

@ -152,7 +152,8 @@ pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
pmd_t *pmd)
{
return;
if (radix_enabled())
prefetch((void *)addr);
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */