Commit 83fe27ea authored by Pranith Kumar's avatar Pranith Kumar Committed by Paul E. McKenney
Browse files

rcu: Make SRCU optional by using CONFIG_SRCU 



SRCU is not necessary to be compiled by default in all cases. For tinification
efforts not compiling SRCU unless necessary is desirable.

The current patch tries to make compiling SRCU optional by introducing a new
Kconfig option CONFIG_SRCU which is selected when any of the components making
use of SRCU are selected.

If we do not select CONFIG_SRCU, srcu.o will not be compiled at all.

   text    data     bss     dec     hex filename
   2007       0       0    2007     7d7 kernel/rcu/srcu.o

Size of arch/powerpc/boot/zImage changes from

   text    data     bss     dec     hex filename
 831552   64180   23944  919676   e087c arch/powerpc/boot/zImage : before
 829504   64180   23952  917636   e0084 arch/powerpc/boot/zImage : after

so the savings are about ~2000 bytes.

Signed-off-by: default avatarPranith Kumar <bobby.prani@gmail.com>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: resolve conflict due to removal of arch/ia64/kvm/Kconfig. ]
parent 9735af5c

arch/arm/kvm/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ config KVM 
	select HAVE_KVM_CPU_RELAX_INTERCEPT

	select KVM_MMIO

	select KVM_ARM_HOST

	select SRCU

	depends on ARM_VIRT_EXT && ARM_LPAE

	---help---

	  Support hosting virtualized guest machines. You will also

arch/arm64/kvm/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ config KVM 
	select KVM_ARM_HOST

	select KVM_ARM_VGIC

	select KVM_ARM_TIMER

	select SRCU

	---help---

	  Support hosting virtualized guest machines.

arch/mips/kvm/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ config KVM 
	select PREEMPT_NOTIFIERS

	select ANON_INODES

	select KVM_MMIO

	select SRCU

	---help---

	  Support for hosting Guest kernels.

	  Currently supported on MIPS32 processors.

arch/powerpc/kvm/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ config KVM 
	select PREEMPT_NOTIFIERS

	select ANON_INODES

	select HAVE_KVM_EVENTFD

	select SRCU



config KVM_BOOK3S_HANDLER

	bool

arch/s390/kvm/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ config KVM 
	select HAVE_KVM_IRQCHIP

	select HAVE_KVM_IRQFD

	select HAVE_KVM_IRQ_ROUTING

	select SRCU

	---help---

	  Support hosting paravirtualized guest machines using the SIE

	  virtualization capability on the mainframe. This should work

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