Re: [PATCH v9 8/8] ABI: sysfs-bus-pci: add documentation for p2pmem allocate

John Hubbard
2022-09-06T01:04:15Z

On 8/25/22 08:24, Logan Gunthorpe wrote:
> Add documentation for the p2pmem/allocate binary file which allows
> for allocating p2pmem buffers in userspace for passing to drivers
> that support them. (Currently only O_DIRECT to NVMe devices.)
>
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> ---
> Documentation/ABI/testing/sysfs-bus-pci | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
> index 6fc2c2efe8ab..dca5e032b4fa 100644
> --- a/Documentation/ABI/testing/sysfs-bus-pci
> +++ b/Documentation/ABI/testing/sysfs-bus-pci
> @@ -171,7 +171,7 @@ Description:
> binary file containing the Vital Product Data for the
> device. It should follow the VPD format defined in
> PCI Specification 2.1 or 2.2, but users should consider
> - that some devices may have incorrectly formatted data.
> + that some devices may have incorrectly formatted data.
> If the underlying VPD has a writable section then the
> corresponding section of this file will be writable.
>
> @@ -407,6 +407,16 @@ Description:
> file contains a '1' if the memory has been published for
> use outside the driver that owns the device.
>
> +What: /sys/bus/pci/devices/.../p2pmem/allocate
> +Date: August 2022
> +Contact: Logan Gunthorpe <logang@deltatee.com>
> +Description:
> + Thes attribute allows mapping p2pmem into userspace. For

s/Thes/This/

Actually, the sentence goes on to say "file", which refers to the same
thing as "attribute". So maybe just saying "This attribute" would be
slightly clearer? So:

This file allows mapping p2pmem into userspace. For

With the typo fix and optionally the "attribute" change (up to you),
please feel free to add:

Reviewed-by: John Hubbard <jhubbard@nvidia.com>

thanks,

--
John Hubbard
NVIDIA

> + each mmap() call on this file, the kernel will allocate
> + a chunk of Peer-to-Peer memory for use in Peer-to-Peer
> + transactions. This memory can be used in O_DIRECT calls
> + to NVMe backed files for Peer-to-Peer copies.
> +
> What: /sys/bus/pci/devices/.../link/clkpm
> /sys/bus/pci/devices/.../link/l0s_aspm
> /sys/bus/pci/devices/.../link/l1_aspm