From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BCB8B4477FA; Mon, 28 Sep 2026 07:01:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790578879; cv=none; b=FektQQIHytRPx7diH5gEciFLynx0w6y4lxy99f5CXQGAAdK7yQHlBtKlw7KxEhPhQz732tqjWVwpyhxA3oUmMpSyTgWTq8Tq/e5P3EXWLPaD0jexbXatKay0XkYMw63i43Tsipq+MtTJQq1ZlXbyPXe/keZ1F4rQv3Re2AbNTUY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790578879; c=relaxed/simple; bh=EF1Bf3xRgXVIHoFpUWDsoa4yst8iMEJYPNjJYnVLq9s=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=cIRcx3hgwf6D2naEm5sT9Tz+HNfGw1UCNPms3Z3xpBjMyr/JjYh/nX5yY1Po6XnIGp7uMM17BKprswHbiOMqC4YF3lrJ+PXGBAl5rYT1dJIyewfq0H2VjA/QxQH7VJta0GeRkKvas8gJCMgON2BlC2bFZAF46pUYIdemXfjLBkU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=GTrYh6Sh; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=qmOblhSw; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="GTrYh6Sh"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="qmOblhSw" Date: Mon, 28 Sep 2026 07:01:13 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1790578875; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WR0BbJxSRhA/IwKshEd+JistSb1mVklr7TKv6Uvn6LU=; b=GTrYh6ShNFYlw7ljGazNeXHJ7rEWgYphGpttl9pHxZgVFQVpkQlqAKjE3kcHKsGmpCkMhK p7vFbVMbRzu6+Aeh3G/psr5ntmluf0quARly19clR5TwW1K24vSknimg8TcPVZztXqi756 QXPpqgWLuyKfDgRUdMwLJT+S1jWMuT6t/3r58mw6lGp1heHkopv8S3g68TIV/gqMa1ARek JOPC60alAnl6w13DO/GDd+plyfpHXiLS0yFClDgbWQMHz+R1z7umVJJTpvod44Nezy7nuF 1ZgC4+1ONlFvm7B2AIQyr2p6EL50lUxZgsV8X2CbZJfvKzZ/JAvkKXeQ6zYqDw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1790578875; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WR0BbJxSRhA/IwKshEd+JistSb1mVklr7TKv6Uvn6LU=; b=qmOblhSwIXbAWrBApGXiRDNNNZPJYPx5ODxudtBeYpAWsKGrN0sfbhmy/pri0fLE09nAFH ERUciPdPTBukYrAQ== From: "tip-bot2 for Shrikanth Hegde" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] virt/steal_governor: Enable the driver Cc: Yury Norov , Shrikanth Hegde , "Peter Zijlstra (Intel)" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20260928053728.797539-14-sshegde@linux.ibm.com> References: <20260928053728.797539-14-sshegde@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <179057887339.3910103.9119829101987077047.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the sched/core branch of tip: Commit-ID: 1fb28c664a19df8d45a6afa04d28d102b04ea680 Gitweb: https://git.kernel.org/tip/1fb28c664a19df8d45a6afa04d28d102b04= ea680 Author: Shrikanth Hegde AuthorDate: Mon, 28 Sep 2026 11:07:28 +05:30 Committer: Peter Zijlstra CommitterDate: Mon, 28 Sep 2026 08:44:44 +02:00 virt/steal_governor: Enable the driver Provide a config option to enable the steal_governor driver. Since the feature targets paravirtualized environments and requires SMP, enforce those dependencies. The driver selects CONFIG_PREFERRED_CPU for the core scheduler mechanisms to work. It is recommended to build the driver as a module (m) instead of built-in (y) due to the following reasons: - Module parameters are read-only after initialization. Building as a module allows updating these parameters by simply reloading the module. Default module parameters cannot work in all configurations. - The driver can be completely disabled by unloading the module. - This feature works best when all VMs operate in a cooperative manner. Requiring an explicit module load ensures intentional deployment across all VMs by the system administrator. Suggested-by: Yury Norov Signed-off-by: Shrikanth Hegde Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20260928053728.797539-14-sshegde@linux.ibm.com --- drivers/virt/Kconfig | 17 +++++++++++++++++ drivers/virt/Makefile | 1 + 2 files changed, 18 insertions(+) diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig index 52eb7e4..eeb84e5 100644 --- a/drivers/virt/Kconfig +++ b/drivers/virt/Kconfig @@ -41,6 +41,23 @@ config FSL_HV_MANAGER 4) A kernel interface for receiving callbacks when a managed partition shuts down. =20 +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 paravirtualized + environments, thereby reducing vCPU preemption costs. + + 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. + More details are at: Documentation/driver-api/steal-governor.rst + + It is recommended to build it as module and load the module + to enable it. + source "drivers/virt/vboxguest/Kconfig" =20 source "drivers/virt/nitro_enclaves/Kconfig" diff --git a/drivers/virt/Makefile b/drivers/virt/Makefile index f29901b..05fb075 100644 --- a/drivers/virt/Makefile +++ b/drivers/virt/Makefile @@ -5,6 +5,7 @@ =20 obj-$(CONFIG_FSL_HV_MANAGER) +=3D fsl_hypervisor.o obj-$(CONFIG_VMGENID) +=3D vmgenid.o +obj-$(CONFIG_STEAL_GOVERNOR) +=3D steal_governor.o obj-y +=3D vboxguest/ =20 obj-$(CONFIG_NITRO_ENCLAVES) +=3D nitro_enclaves/