From: "Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com> change_prot_numa should work even if _PAGE_NUMA != _PAGE_PROTNONE. On archs like ppc64 that don't use _PAGE_PROTNONE and also have a separate page table outside linux pagetable, we just need to make sure that when calling change_prot_numa we flush the hardware page table entry so that next page access result in a numa fault.
We still need to make sure we use the numa faulting logic only when CONFIG_NUMA_BALANCING is set. This implies the migrate-on-fault (Lazy migration) via mbind will only work if CONFIG_NUMA_BALANCING is set. Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com> --- Previous discussion around the patch can be found at http://article.gmane.org/gmane.linux.kernel.mm/109305 changes from V2: * Move the numa faulting definition within CONFIG_NUMA_BALANCING include/linux/mm.h | 2 +- mm/mempolicy.c | 5 ++--- 2 files changed, 3 insertions(+), 4 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 1cedd000cf29..a7b4e310bf42 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1842,7 +1842,7 @@ static inline pgprot_t vm_get_page_prot(unsigned long vm_flags) } #endif -#ifdef CONFIG_ARCH_USES_NUMA_PROT_NONE +#ifdef CONFIG_NUMA_BALANCING unsigned long change_prot_numa(struct vm_area_struct *vma, unsigned long start, unsigned long end); #endif diff --git a/mm/mempolicy.c b/mm/mempolicy.c index eca4a3129129..9f73b29d304d 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -613,7 +613,7 @@ static inline int queue_pages_pgd_range(struct vm_area_struct *vma, return 0; } -#ifdef CONFIG_ARCH_USES_NUMA_PROT_NONE +#ifdef CONFIG_NUMA_BALANCING /* * This is used to mark a range of virtual addresses to be inaccessible. * These are later cleared by a NUMA hinting fault. Depending on these @@ -627,7 +627,6 @@ unsigned long change_prot_numa(struct vm_area_struct *vma, unsigned long addr, unsigned long end) { int nr_updated; - BUILD_BUG_ON(_PAGE_NUMA != _PAGE_PROTNONE); nr_updated = change_protection(vma, addr, end, vma->vm_page_prot, 0, 1); if (nr_updated) @@ -641,7 +640,7 @@ static unsigned long change_prot_numa(struct vm_area_struct *vma, { return 0; } -#endif /* CONFIG_ARCH_USES_NUMA_PROT_NONE */ +#endif /* CONFIG_NUMA_BALANCING */ /* * Walk through page tables and collect pages to be migrated. -- 1.8.3.2 _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
