Re: [PATCH 02/12] pci-p2p: Add sysfs group to display p2pmem stats

Bjorn Helgaas
2018-01-04T21:50:40Z

On Thu, Jan 04, 2018 at 12:01:27PM -0700, Logan Gunthorpe wrote:
> Attributes display the total amount of P2P memory, the ammount available
> and whether it is published or not.

s/ammount/amount/ (also below)

> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> ---
> Documentation/ABI/testing/sysfs-bus-pci | 25 ++++++++++++++++
> drivers/pci/p2p.c | 51 +++++++++++++++++++++++++++++++++
> 2 files changed, 76 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
> index 44d4b2be92fd..7b80ea77faca 100644
> --- a/Documentation/ABI/testing/sysfs-bus-pci
> +++ b/Documentation/ABI/testing/sysfs-bus-pci
> @@ -323,3 +323,28 @@ Description:
>
> This is similar to /sys/bus/pci/drivers_autoprobe, but
> affects only the VFs associated with a specific PF.
> +
> +What: /sys/bus/pci/devices/.../p2pmem/available

I wonder if "p2pdma" would be a more suggestive term? It's not really
the *memory* that is peer-to-peer; the peer-to-peer part is referring
to *access* to the memory.

> @@ -82,6 +130,9 @@ static int pci_p2pmem_setup(struct pci_dev *pdev)
> if (error)
> goto out_pool_destroy;
>
> + if (sysfs_create_group(&pdev->dev.kobj, &p2pmem_group))
> + dev_warn(&pdev->dev, "failed to create p2p sysfs group\n");

Not sure the warning (by itself) is worthwhile. If we were going to
disable the feature if sysfs_create_group() failed, that's one thing,
but we aren't doing anything except generating a warning, which the
user can't really do anything with. If the user is looking for the
sysfs file, its absence will be obvious even without the message.

> pdev->p2p = p2p;
>
> return 0;
> --
> 2.11.0
>