[PATCH] Drivers: hv: Kconfig: select CPUMASK_OFFSTACK for Hyper-V

From: Saurabh Sengar
Date: Fri Feb 16 2024 - 09:10:38 EST


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@xxxxxxxxxxxxxxxxxxx>
---
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