s390: remove small stack config option

We've seen repeatedly that 8KB stack size on 64 bit kernels
is not sufficient.
So simply remove the config option.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index eb8fb62..bda6ba6 100644 (file)
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -375,19 +375,6 @@ config PACK_STACK
 
          Say Y if you are unsure.
 
-config SMALL_STACK
-       def_bool n
-       prompt "Use 8kb for kernel stack instead of 16kb"
-       depends on PACK_STACK && 64BIT && !LOCKDEP
-       help
-         If you say Y here and the compiler supports the -mkernel-backchain
-         option the kernel will use a smaller kernel stack size. The reduced
-         size is 8kb instead of 16kb. This allows to run more threads on a
-         system and reduces the pressure on the memory management for higher
-         order page allocations.
-
-         Say N if you are unsure.
-
 config CHECK_STACK
        def_bool y
        prompt "Detect kernel stack overflow"

diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index 7e3ce78..a7d68a4 100644 (file)
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -55,22 +55,12 @@ cflags-$(CONFIG_FRAME_POINTER) += -fno-optimize-sibling-calls
 ifeq ($(call cc-option-yn,-mkernel-backchain),y)
 cflags-$(CONFIG_PACK_STACK)  += -mkernel-backchain -D__PACK_STACK
 aflags-$(CONFIG_PACK_STACK)  += -D__PACK_STACK
-cflags-$(CONFIG_SMALL_STACK) += -D__SMALL_STACK
-aflags-$(CONFIG_SMALL_STACK) += -D__SMALL_STACK
-ifdef CONFIG_SMALL_STACK
-STACK_SIZE := $(shell echo $$(($(STACK_SIZE)/2)) )
-endif
 endif
 
 # new style option for packed stacks
 ifeq ($(call cc-option-yn,-mpacked-stack),y)
 cflags-$(CONFIG_PACK_STACK)  += -mpacked-stack -D__PACK_STACK
 aflags-$(CONFIG_PACK_STACK)  += -D__PACK_STACK
-cflags-$(CONFIG_SMALL_STACK) += -D__SMALL_STACK
-aflags-$(CONFIG_SMALL_STACK) += -D__SMALL_STACK
-ifdef CONFIG_SMALL_STACK
-STACK_SIZE := $(shell echo $$(($(STACK_SIZE)/2)) )
-endif
 endif
 
 ifeq ($(call cc-option-yn,-mstack-size=8192 -mstack-guard=128),y)

diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h
index 51035e5..eb5f64d 100644 (file)
--- a/arch/s390/include/asm/thread_info.h
+++ b/arch/s390/include/asm/thread_info.h
@@ -14,13 +14,8 @@
 #define THREAD_ORDER 1
 #define ASYNC_ORDER  1
 #else /* CONFIG_64BIT */
-#ifndef __SMALL_STACK
 #define THREAD_ORDER 2
 #define ASYNC_ORDER  2
-#else
-#define THREAD_ORDER 1
-#define ASYNC_ORDER  1
-#endif
 #endif /* CONFIG_64BIT */
 
 #define THREAD_SIZE (PAGE_SIZE << THREAD_ORDER)