Re: [PATCH 03/15] devlink: add operation to take an immediate snapshot
From: Jiri Pirko <jiri@resnulli.us>
Date: 2020-02-03 11:50:06
Thu, Jan 30, 2020 at 11:58:58PM CET, jacob.e.keller@intel.com wrote:
quoted hunk ↗ jump to hunk
Add a new devlink command, DEVLINK_CMD_REGION_TAKE_SNAPSHOT. This command is intended to enable userspace to request an immediate snapshot of a region. Regions can enable support for requestable snapshots by implementing the snapshot callback function in the region's devlink_region_ops structure. Implementations of this function callback should capture an immediate copy of the data and return it and its destructor in the function parameters. The core devlink code will generate a snapshot ID and create the new snapshot while holding the devlink instance lock. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> --- .../networking/devlink/devlink-region.rst | 9 +++- include/net/devlink.h | 7 +++ include/uapi/linux/devlink.h | 2 + net/core/devlink.c | 46 +++++++++++++++++++ 4 files changed, 62 insertions(+), 2 deletions(-)diff --git a/Documentation/networking/devlink/devlink-region.rst b/Documentation/networking/devlink/devlink-region.rst index 1a7683e7acb2..262249e6c3fc 100644 --- a/Documentation/networking/devlink/devlink-region.rst +++ b/Documentation/networking/devlink/devlink-region.rst@@ -20,6 +20,11 @@ address regions that are otherwise inaccessible to the user.Regions may also be used to provide an additional way to debug complex error states, but see also :doc:`devlink-health` +Regions may optionally support capturing a snapshot on demand via the +``DEVLINK_CMD_REGION_TAKE_SNAPSHOT`` netlink message. A driver wishing to +allow requested snapshots must implement the ``.snapshot`` callback for the +region in its ``devlink_region_ops`` structure. + example usage -------------@@ -40,8 +45,8 @@ example usage # Delete a snapshot using: $ devlink region del pci/0000:00:05.0/cr-space snapshot 1 - # Trigger (request) a snapshot be taken: - $ devlink region trigger pci/0000:00:05.0/cr-space + # Request an immediate snapshot, if supported by the region + $ devlink region snapshot pci/0000:00:05.0/cr-space
Hmm, the shapshot is now removed by user calling: $ devlink region del DEV/REGION snapshot SNAPSHOT_ID That is using DEVLINK_CMD_REGION_DEL netlink command calling devlink_nl_cmd_region_del() I think the creation should be symmetric. Something like: $ devlink region add DEV/REGION snapshot SNAPSHOT_ID SNAPSHOT_ID is either exact number or "any" if user does not care. The benefit of using user-passed ID value is that you can use this easily in scripts. The existing unused netlink command DEVLINK_CMD_REGION_NEW would be used for this.
# Dump a snapshot:
$ devlink region dump pci/0000:00:05.0/fw-health snapshot 1[...]