This patch is part of the architecture backend for thp on System z. It disables thp for kvm hosts, because there is no kvm host hugepage support so far. Existing thp mappings are split using follow_page() with FOLL_SPLIT, and future thp mappings are prevented by setting VM_NOHUGEPAGE in mm->def_flags. Signed-off-by: Gerald Schaefer --- arch/s390/mm/pgtable.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -787,6 +787,30 @@ void tlb_remove_table(struct mmu_gather tlb_table_flush(tlb); } +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +void thp_split_vma(struct vm_area_struct *vma) +{ + unsigned long addr; + struct page *page; + + for (addr = vma->vm_start; addr < vma->vm_end; addr += PAGE_SIZE) { + page = follow_page(vma, addr, FOLL_SPLIT); + } +} + +void thp_split_mm(struct mm_struct *mm) +{ + struct vm_area_struct *vma = mm->mmap; + + while (vma != NULL) { + thp_split_vma(vma); + vma->vm_flags &= ~VM_HUGEPAGE; + vma->vm_flags |= VM_NOHUGEPAGE; + vma = vma->vm_next; + } +} +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ + /* * switch on pgstes for its userspace process (for kvm) */ @@ -824,6 +848,12 @@ int s390_enable_sie(void) if (!mm) return -ENOMEM; +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + /* split thp mappings and disable thp for future mappings */ + thp_split_mm(mm); + mm->def_flags |= VM_NOHUGEPAGE; +#endif + /* Now lets check again if something happened */ task_lock(tsk); if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 || -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/