Re: [PATCH] Improve Atheros ethernet driver not to do order 4 GFP_ATOMIC allocation

From: Eric Dumazet
Date: Mon Nov 30 2015 - 12:58:38 EST


On Sat, 2015-11-28 at 15:51 +0100, Pavel Machek wrote:
> atl1c driver is doing order-4 allocation with GFP_ATOMIC
> priority. That often breaks networking after resume. Switch to
> GFP_KERNEL. Still not ideal, but should be significantly better.
>
> Signed-off-by: Pavel Machek <pavel@xxxxxx>
>
> diff --git a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
> index 2795d6d..afb71e0 100644
> --- a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
> +++ b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
> @@ -1016,10 +1016,10 @@ static int atl1c_setup_ring_resources(struct atl1c_adapter *adapter)
> sizeof(struct atl1c_recv_ret_status) * rx_desc_count +
> 8 * 4;
>
> - ring_header->desc = pci_alloc_consistent(pdev, ring_header->size,
> - &ring_header->dma);
> + ring_header->desc = dma_alloc_coherent(&pdev->dev, ring_header->size,
> + &ring_header->dma, GFP_KERNEL);
> if (unlikely(!ring_header->desc)) {
> - dev_err(&pdev->dev, "pci_alloc_consistend failed\n");
> + dev_err(&pdev->dev, "could not get memmory for DMA buffer\n");
> goto err_nomem;
> }
> memset(ring_header->desc, 0, ring_header->size);
>

It seems there is a missed opportunity to get rid of the memset() here,
by adding __GFP_ZERO to the dma_alloc_coherent() GFP_KERNEL mask,
or simply using dma_zalloc_coherent()





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