diff options
| author | Kimberly Brown <kimbrownkd@gmail.com> | 2019-03-19 00:04:01 -0400 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2019-03-20 23:55:56 -0400 |
| commit | 46fc15487d02451448c11b83c4d086d87a6ad588 (patch) | |
| tree | 65420705efeb4871aaa3a936e228bd8f8d8d6253 /Documentation/ABI/stable/sysfs-bus-vmbus | |
| parent | 9e98c678c2d6ae3a17cb2de55d17f69dddaa231b (diff) | |
Drivers: hv: vmbus: Expose monitor data only when monitor pages are used
There are two methods for signaling the host: the monitor page mechanism
and hypercalls. The monitor page mechanism is used by performance
critical channels (storage, networking, etc.) because it provides
improved throughput. However, latency is increased. Monitor pages are
allocated to these channels.
Monitor pages are not allocated to channels that do not use the monitor
page mechanism. Therefore, these channels do not have a valid monitor id
or valid monitor page data. In these cases, some of the "_show"
functions return incorrect data. They return an invalid monitor id and
data that is beyond the bounds of the hv_monitor_page array fields.
The "channel->offermsg.monitor_allocated" value can be used to determine
whether monitor pages have been allocated to a channel.
Add "is_visible()" callback functions for the device-level and
channel-level attribute groups. These functions will hide the monitor
sysfs files when the monitor mechanism is not used.
Remove ".default_attributes" from "vmbus_chan_attrs" and create a
channel-level attribute group. These changes allow the new
"is_visible()" callback function to be applied to the channel-level
attributes.
Call "sysfs_create_group()" in "vmbus_add_channel_kobj()" to create the
channel's sysfs files. Add a new function,
“vmbus_remove_channel_attr_group()”, and call it in "free_channel()" to
remove the channel's sysfs files when the channel is closed.
Signed-off-by: Kimberly Brown <kimbrownkd@gmail.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'Documentation/ABI/stable/sysfs-bus-vmbus')
| -rw-r--r-- | Documentation/ABI/stable/sysfs-bus-vmbus | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/Documentation/ABI/stable/sysfs-bus-vmbus b/Documentation/ABI/stable/sysfs-bus-vmbus index 826689dcc2e6..8e8d167eca31 100644 --- a/Documentation/ABI/stable/sysfs-bus-vmbus +++ b/Documentation/ABI/stable/sysfs-bus-vmbus @@ -81,7 +81,9 @@ What: /sys/bus/vmbus/devices/<UUID>/channels/<N>/latency Date: September. 2017 KernelVersion: 4.14 Contact: Stephen Hemminger <sthemmin@microsoft.com> -Description: Channel signaling latency +Description: Channel signaling latency. This file is available only for + performance critical channels (storage, network, etc.) that use + the monitor page mechanism. Users: Debugging tools What: /sys/bus/vmbus/devices/<UUID>/channels/<N>/out_mask @@ -95,7 +97,9 @@ What: /sys/bus/vmbus/devices/<UUID>/channels/<N>/pending Date: September. 2017 KernelVersion: 4.14 Contact: Stephen Hemminger <sthemmin@microsoft.com> -Description: Channel interrupt pending state +Description: Channel interrupt pending state. This file is available only for + performance critical channels (storage, network, etc.) that use + the monitor page mechanism. Users: Debugging tools What: /sys/bus/vmbus/devices/<UUID>/channels/<N>/read_avail @@ -137,7 +141,9 @@ What: /sys/bus/vmbus/devices/<UUID>/channels/<N>/monitor_id Date: January. 2018 KernelVersion: 4.16 Contact: Stephen Hemminger <sthemmin@microsoft.com> -Description: Monitor bit associated with channel +Description: Monitor bit associated with channel. This file is available only + for performance critical channels (storage, network, etc.) that + use the monitor page mechanism. Users: Debugging tools and userspace drivers What: /sys/bus/vmbus/devices/<UUID>/channels/<N>/ring |