[PATCH v10 8/8] ABI: sysfs-bus-pci: add documentation for p2pmem allocate

Logan Gunthorpe
2022-09-22T16:40:52Z

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>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
---
Documentation/ABI/testing/sysfs-bus-pci | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index 6fc2c2efe8ab..f4602b8d6e11 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -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:
+ This file allows mapping p2pmem into userspace. For 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
--
2.30.2