Re: [PATCH v3 1/8] mm/dax: Dump start address in fault handler

David Hildenbrand
2024-07-31T12:04:44Z

On 15.07.24 21:21, Peter Xu wrote:
> Currently the dax fault handler dumps the vma range when dynamic debugging
> enabled. That's mostly not useful. Dump the (aligned) address instead
> with the order info.
>
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
> drivers/dax/device.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/dax/device.c b/drivers/dax/device.c
> index eb61598247a9..714174844ca5 100644
> --- a/drivers/dax/device.c
> +++ b/drivers/dax/device.c
> @@ -235,9 +235,9 @@ static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf, unsigned int order)
> int id;
> struct dev_dax *dev_dax = filp->private_data;
>
> - dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) order:%d\n", current->comm,
> - (vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
> - vmf->vma->vm_start, vmf->vma->vm_end, order);
> + dev_dbg(&dev_dax->dev, "%s: op=%s addr=%#lx order=%d\n", current->comm,
> + (vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
> + vmf->address & ~((1UL << (order + PAGE_SHIFT)) - 1), order);
>
> id = dax_read_lock();
> if (order == 0)

Agreed, the address of the fault is better. Just wondering, would the
unmasked address be even better? Using the order we can figure out the
to-be-aligned address.

Acked-by: David Hildenbrand <david@redhat.com>

--
Cheers,

David / dhildenb