Received-SPF: pass (google.com: domain of linux-kernel+bounces-68712-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
From: Saurabh Sengar <ssengar@linux.microsoft.com>
To: kys@microsoft.com,
	haiyangz@microsoft.com,
	wei.liu@kernel.org,
	decui@microsoft.com,
	linux-hyperv@vger.kernel.org,
	linux-kernel@vger.kernel.org
Cc: ssengar@microsoft.com
Subject: [PATCH] Drivers: hv: Kconfig: select CPUMASK_OFFSTACK for Hyper-V
Date: Fri, 16 Feb 2024 06:10:03 -0800
Message-Id: <1708092603-14504-1-git-send-email-ssengar@linux.microsoft.com>
Precedence: bulk

CPUMASK_OFFSTACK must be set to have NR_CPUS_RANGE_END value greater than
512, which eventually allows NR_CPUS > 512.

CPUMASK_OFFSTACK can also be enabled by setting MAXSMP=y, but that will
set NR_CPUS=8192. This is not accurate for Hyper-V, because maximum number
of vCPU supported by Hyper-V today is 2048. Thus, enabling MAXSMP increase
the vmlinux size unnecessary.

This option allows NR_CPUS=2048 which saves around 1MB of vmlinux size for
Hyper-V.

Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
---
 drivers/hv/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
index 0024210..bc3f496 100644
--- a/drivers/hv/Kconfig
+++ b/drivers/hv/Kconfig
@@ -9,6 +9,7 @@ config HYPERV
 	select PARAVIRT
 	select X86_HV_CALLBACK_VECTOR if X86
 	select OF_EARLY_FLATTREE if OF
+	select CPUMASK_OFFSTACK
 	help
 	  Select this option to run Linux as a Hyper-V client operating
 	  system.
-- 
1.8.3.1