On Mon, Sep 16, 2024 at 11:08 PM Dev Jain <dev.jain@xxxxxxx> wrote:
>
> In preparation for the second patch, make pte_range_none() return
> the number of contiguous empty PTEs.
>
> Signed-off-by: Dev Jain <dev.jain@xxxxxxx>
> ---
> mm/memory.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/mm/memory.c b/mm/memory.c
> index 6469ac99f2f7..8bb1236de93c 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -4617,16 +4617,16 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
> return ret;
> }
>
> -static bool pte_range_none(pte_t *pte, int nr_pages)
> +static int pte_range_none(pte_t *pte, int nr_pages)
> {
> int i;
>
> for (i = 0; i < nr_pages; i++) {
> if (!pte_none(ptep_get_lockless(pte + i)))
> - return false;
> + return i;
> }
>
> - return true;
> + return nr_pages;
> }
>
> static struct folio *alloc_anon_folio(struct vm_fault *vmf)
> @@ -4671,7 +4671,7 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf)
> order = highest_order(orders);
> while (orders) {
> addr = ALIGN_DOWN(vmf->address, PAGE_SIZE << order);
> - if (pte_range_none(pte + pte_index(addr), 1 << order))
> + if (pte_range_none(pte + pte_index(addr), 1 << order) == 1 << order)
Minor suggestion: it's a bit odd that we're doing 1 << order twice.
Perhaps consider
introducing a local variable, nr_pages, for clarity.
Otherwise,
Reviewed-by: Barry Song <baohua@xxxxxxxxxx>
> break;
> order = next_order(&orders, order);
> }
> @@ -4787,7 +4787,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
> if (nr_pages == 1 && vmf_pte_changed(vmf)) {
> update_mmu_tlb(vma, addr, vmf->pte);
> goto release;
> - } else if (nr_pages > 1 && !pte_range_none(vmf->pte, nr_pages)) {
> + } else if (nr_pages > 1 && pte_range_none(vmf->pte, nr_pages) != nr_pages) {
> update_mmu_tlb_range(vma, addr, vmf->pte, nr_pages);
> goto release;
> }
> @@ -5121,7 +5121,7 @@ vm_fault_t finish_fault(struct vm_fault *vmf)
> update_mmu_tlb(vma, addr, vmf->pte);
> ret = VM_FAULT_NOPAGE;
> goto unlock;
> - } else if (nr_pages > 1 && !pte_range_none(vmf->pte, nr_pages)) {
> + } else if (nr_pages > 1 && pte_range_none(vmf->pte, nr_pages) != nr_pages) {
> update_mmu_tlb_range(vma, addr, vmf->pte, nr_pages);
> ret = VM_FAULT_NOPAGE;
> goto unlock;
> --
> 2.30.2
>
Thanks
Barry
