netdev - Re: [PATCH v4 0/3] thermal/netlink/intel_hfi: Enable HFI feature only when required

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAJZ5v0gw52e9zx36YgVLDO9jJw+80BP0e_C92kYyq-ys=f8pBw@mail.gmail.com>
Date: Thu, 29 Feb 2024 16:18:50 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Stanislaw Gruszka <stanislaw.gruszka@...ux.intel.com>
Cc: linux-pm@...r.kernel.org, "Rafael J. Wysocki" <rafael@...nel.org>, 
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>, 
	Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>, 
	Daniel Lezcano <daniel.lezcano@...aro.org>, "David S. Miller" <davem@...emloft.net>, 
	Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
	Jiri Pirko <jiri@...nulli.us>, Johannes Berg <johannes@...solutions.net>, 
	Florian Westphal <fw@...len.de>, netdev@...r.kernel.org
Subject: Re: [PATCH v4 0/3] thermal/netlink/intel_hfi: Enable HFI feature only
 when required

On Mon, Feb 12, 2024 at 5:16 PM Stanislaw Gruszka
<stanislaw.gruszka@...ux.intel.com> wrote:
>
> The patchset introduces a new genetlink family bind/unbind callbacks
> and thermal/netlink notifications, which allow drivers to send netlink
> multicast events based on the presence of actual user-space consumers.
> This functionality optimizes resource usage by allowing disabling
> of features when not needed.
>
> Then implement the notification mechanism in the intel_hif driver,
> it is utilized to disable the Hardware Feedback Interface (HFI)
> dynamically. By implementing a thermal genl notify callback, the driver
> can now enable or disable the HFI based on actual demand, particularly
> when user-space applications like intel-speed-select or Intel Low Power
> daemon utilize events related to performance and energy efficiency
> capabilities.
>
> On machines where Intel HFI is present, but there are no user-space
> components installed, we can save tons of CPU cycles.
>
> Changes v3 -> v4:
>
> - Add 'static inline' in patch2
>
> Changes v2 -> v3:
>
> - Fix unused variable compilation warning
> - Add missed Suggested by tag to patch2
>
> Changes v1 -> v2:
>
> - Rewrite using netlink_bind/netlink_unbind callbacks.
>
> - Minor changelog tweaks.
>
> - Add missing check in intel hfi syscore resume (had it on my testing,
> but somehow missed in post).
>
> - Do not use netlink_has_listeners() any longer, use custom counter instead.
> To keep using netlink_has_listners() would be required to rearrange
> netlink_setsockopt() and possibly netlink_bind() functions, to call
> nlk->netlink_bind() after listeners are updated. So I decided to custom
> counter. This have potential issue as thermal netlink registers before
> intel_hif, so theoretically intel_hif can miss events. But since both
> are required to be kernel build-in (if CONFIG_INTEL_HFI_THERMAL is
> configured), they start before any user-space.
>
> v1: https://lore.kernel.org/linux-pm/20240131120535.933424-1-stanislaw.gruszka@linux.intel.com//
> v2: https://lore.kernel.org/linux-pm/20240206133605.1518373-1-stanislaw.gruszka@linux.intel.com/
> v3: https://lore.kernel.org/linux-pm/20240209120625.1775017-1-stanislaw.gruszka@linux.intel.com/
>
> Stanislaw Gruszka (3):
>   genetlink: Add per family bind/unbind callbacks
>   thermal: netlink: Add genetlink bind/unbind notifications
>   thermal: intel: hfi: Enable interface only when required
>
>  drivers/thermal/intel/intel_hfi.c | 95 +++++++++++++++++++++++++++----
>  drivers/thermal/thermal_netlink.c | 40 +++++++++++--
>  drivers/thermal/thermal_netlink.h | 26 +++++++++
>  include/net/genetlink.h           |  4 ++
>  net/netlink/genetlink.c           | 30 ++++++++++
>  5 files changed, 180 insertions(+), 15 deletions(-)
>
> --

What tree is this based on?