sh: Add support for 4K stacks.

This enables support for 4K stacks on SH.

Currently this depends on DEBUG_KERNEL, but likely all boards
will switch to this as the default in the future.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug
index f0188e626be0..48479e014dac 100644
--- a/arch/sh/Kconfig.debug
+++ b/arch/sh/Kconfig.debug
@@ -46,6 +46,16 @@ config DEBUG_STACK_USAGE
 
           This option will slow down process creation somewhat.
 
+config 4KSTACKS
+        bool "Use 4Kb for kernel stacks instead of 8Kb"
+        depends on DEBUG_KERNEL
+        help
+          If you say Y here the kernel will use a 4Kb stacksize for the
+          kernel stack attached to each process/thread. This facilitates
+          running more threads on a system and also reduces the pressure
+          on the VM subsystem for higher order allocations. This option
+          will also use IRQ stacks to compensate for the reduced stackspace.
+
 config KGDB
         bool "Include KGDB kernel debugger"
         select FRAME_POINTER