From: Shrikanth Hegde <sshegde@linux.ibm.com>
To: linux-kernel@vger.kernel.org, mingo@kernel.org,
peterz@infradead.org, juri.lelli@redhat.com,
vincent.guittot@linaro.org, yury.norov@gmail.com,
kprateek.nayak@amd.com, iii@linux.ibm.com, corbet@lwn.net
Cc: sshegde@linux.ibm.com, tglx@kernel.org,
gregkh@linuxfoundation.org, pbonzini@redhat.com,
seanjc@google.com, vschneid@redhat.com, huschle@linux.ibm.com,
rostedt@goodmis.org, dietmar.eggemann@arm.com,
maddy@linux.ibm.com, srikar@linux.ibm.com, hdanton@sina.com,
chleroy@kernel.org, vineeth@bitbyteword.org, frederic@kernel.org,
arighi@nvidia.com, pauld@redhat.com, christian.loehle@arm.com,
tj@kernel.org, tommaso.cucinotta@gmail.com, maz@kernel.org,
rafael@kernel.org, rdunlap@infradead.org, kernellwp@gmail.com,
linux-doc@vger.kernel.org, jgross@suse.com,
virtualization@lists.linux.dev
Subject: [PATCH v8 11/11] virt/steal_governor: Enable the driver
Date: Mon, 20 Jul 2026 22:52:50 +0530 [thread overview]
Message-ID: <20260720172250.2257582-12-sshegde@linux.ibm.com> (raw)
In-Reply-To: <20260720172250.2257582-1-sshegde@linux.ibm.com>
Provide a config option for users to enable the driver.
Since the feature works for paravirtualized case and make sense only
with SMP, enforce those dependencies. Driver is going to select
CONFIG_PREFERRED_CPU=y for scheduler mechanisms to work.
It is recommended to build the driver as module instead of yes
due to below reasons.
- Module parameters are read only after init. If one wants to change
them having as module allows that.
- Driver can be disabled if it is built as module.
- If it is module, admin user has to enable it. Since this feature works
best when all VMs work in co-operative manner, admin will likely
enable it in all VMs.
Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
---
drivers/virt/Kconfig | 2 ++
drivers/virt/Makefile | 1 +
drivers/virt/steal_governor/Kconfig | 18 ++++++++++++++++++
drivers/virt/steal_governor/Makefile | 6 ++++++
4 files changed, 27 insertions(+)
create mode 100644 drivers/virt/steal_governor/Kconfig
create mode 100644 drivers/virt/steal_governor/Makefile
diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig
index 52eb7e4ba71f..4fbc928022a4 100644
--- a/drivers/virt/Kconfig
+++ b/drivers/virt/Kconfig
@@ -47,6 +47,8 @@ source "drivers/virt/nitro_enclaves/Kconfig"
source "drivers/virt/acrn/Kconfig"
+source "drivers/virt/steal_governor/Kconfig"
+
endif
source "drivers/virt/coco/Kconfig"
diff --git a/drivers/virt/Makefile b/drivers/virt/Makefile
index f29901bd7820..512dcfd6c73e 100644
--- a/drivers/virt/Makefile
+++ b/drivers/virt/Makefile
@@ -10,3 +10,4 @@ obj-y += vboxguest/
obj-$(CONFIG_NITRO_ENCLAVES) += nitro_enclaves/
obj-$(CONFIG_ACRN_HSM) += acrn/
obj-y += coco/
+obj-$(CONFIG_STEAL_GOVERNOR) += steal_governor/
diff --git a/drivers/virt/steal_governor/Kconfig b/drivers/virt/steal_governor/Kconfig
new file mode 100644
index 000000000000..926bb351db4f
--- /dev/null
+++ b/drivers/virt/steal_governor/Kconfig
@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config STEAL_GOVERNOR
+ tristate "Dynamic vCPU management based on steal time"
+ depends on PARAVIRT && SMP
+ select PREFERRED_CPU
+ default m
+ help
+ This driver helps to reduce the steal time in paravirtualised
+ environment, thereby reducing vCPU preemption. Reducing vCPU
+ preemption provides improved lock holder preemption and reduces
+ cost of vCPU preemption in the host.
+
+ By default preferred CPUs will be same as active CPUs. Depending
+ on the steal time when steal_governor driver is enabled,
+ preferred CPUs could become subset of active CPUs.
+
+ It is recommended to build it as module and load the module
+ to enable it.
diff --git a/drivers/virt/steal_governor/Makefile b/drivers/virt/steal_governor/Makefile
new file mode 100644
index 000000000000..eb90ed6b94d7
--- /dev/null
+++ b/drivers/virt/steal_governor/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Steal time governor to alter preferred CPU state.
+obj-$(CONFIG_STEAL_GOVERNOR) += steal_governor.o
+
+steal_governor-y := core.o
--
2.47.3
prev parent reply other threads:[~2026-07-20 17:25 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-20 17:22 [PATCH v8 00/11] sched, steal_governor: Introduce cpu_preferred_mask and steal-driven vCPU backoff Shrikanth Hegde
2026-07-20 17:22 ` [PATCH v8 01/11] sched/docs: Document cpu_preferred_mask and Preferred CPU concept Shrikanth Hegde
2026-07-20 17:22 ` [PATCH v8 02/11] cpumask: Introduce cpu_preferred_mask Shrikanth Hegde
2026-07-20 17:22 ` [PATCH v8 03/11] sysfs: Add preferred CPU file Shrikanth Hegde
2026-07-20 17:22 ` [PATCH v8 04/11] sched/core: Try to use a preferred CPU in is_cpu_allowed Shrikanth Hegde
2026-07-20 17:22 ` [PATCH v8 05/11] sched/fair: Load balance only among preferred CPUs Shrikanth Hegde
2026-07-20 17:22 ` [PATCH v8 06/11] sched/core: Push current task from non preferred CPU Shrikanth Hegde
2026-07-20 17:22 ` [PATCH v8 07/11] sched/debug: Add migration stats due to non preferred CPUs Shrikanth Hegde
2026-07-20 17:22 ` [PATCH v8 08/11] virt: Introduce steal governor driver Shrikanth Hegde
2026-07-21 17:09 ` Yury Norov
2026-07-20 17:22 ` [PATCH v8 09/11] virt/steal_governor: Add control knobs for handling steal values Shrikanth Hegde
2026-07-20 17:22 ` [PATCH v8 10/11] virt/steal_governor: Implement steal_governor policy loop Shrikanth Hegde
2026-07-21 19:28 ` Yury Norov
2026-07-20 17:22 ` Shrikanth Hegde [this message]
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