Reviewed-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> ---
> v1->v2:
>
> Merged up to vfio/next
>
> Moved the cond_resched() to a more appropriate place within the
> loop, and added a comment about why it's there.
>
> Update to change log describing one of the consequences of not doing
> this.
>
> drivers/vfio/vfio_iommu_type1.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 1136d7ac6b597..ad599b1601711 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -647,6 +647,13 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
>
> while (npage) {
> if (!batch->size) {
> + /*
> + * Large mappings may take a while to repeatedly refill
> + * the batch, so conditionally relinquish the CPU when
> + * needed to avoid stalls.
> + */
> + cond_resched();
> +
> /* Empty batch, so refill it. */
> ret = vaddr_get_pfns(mm, vaddr, npage, dma->prot,
> &pfn, batch);
> --
> 2.47.1
>
