Rename 16KSTACKS to DEBUG_STACKS.
arch/arc/Kconfig.debug says that the default stack size is 8KB
and it will become 16KB stack if 16KSTACKS is set.
However, the stack size is based on PAGE_SIZE, and it is
configurable by CONFIG_ARC_PAGE_SIZE_16K or CONFIG_ARC_PAGE_SIZE_4K.
When CONFIG_16KSTACKS=y:
PAGE_SHIFT==12 => THREAD_SIZE == (1 << (12 + 1)) = 8KB
PAGE_SHIFT==13 => THREAD_SIZE == (1 << (13 + 1)) = 16KB
PAGE_SHIFT==14 => THREAD_SIZE == (1 << (14 + 1)) = 32KB
We get correct 16KB stack only when PAGE_SHIFT is 13.
See arch/arc/include/uapi/asm/page.h:
/* PAGE_SHIFT determines the page size */
\#if defined(CONFIG_ARC_PAGE_SIZE_16K)
\#define PAGE_SHIFT 14
\#elif defined(CONFIG_ARC_PAGE_SIZE_4K)
\#define PAGE_SHIFT 12
\#else
\#define PAGE_SHIFT 13
\#endif
See arch/arc/include/asm/thread_info.h:
\#ifdef CONFIG_DEBUG_STACKS
\#define THREAD_SIZE_ORDER 1
\#else
\#define THREAD_SIZE_ORDER 0
\#endif
\#define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER)
\#define THREAD_SHIFT (PAGE_SHIFT + THREAD_SIZE_ORDER)
To make CONFIG_16KSTACKS less confusing, rename it to DEBUG_STACKS
(as it is defined in Kconfig.debug) and modify the Kconfig
description. No functional changes intended.
Signed-off-by: Min-Hua Chen <[email protected]>
---
arch/arc/Kconfig.debug | 7 ++++---
arch/arc/include/asm/thread_info.h | 2 +-
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/arch/arc/Kconfig.debug b/arch/arc/Kconfig.debug
index 45add86decd5..9a1e140605c4 100644
--- a/arch/arc/Kconfig.debug
+++ b/arch/arc/Kconfig.debug
@@ -1,10 +1,11 @@
# SPDX-License-Identifier: GPL-2.0
-config 16KSTACKS
- bool "Use 16Kb for kernel stacks instead of 8Kb"
+config DEBUG_STACKS
+ bool "Use double sized kernel stacks"
help
- If you say Y here the kernel will use a 16Kb stacksize for the
+ If you say Y here the kernel will use a double sized stack for the
kernel stack attached to each process/thread. The default is 8K.
+ (depends on CONFIG_ARC_PAGE_SIZE_16K or CONFIG_ARC_PAGE_SIZE_4K)
This increases the resident kernel footprint and will cause less
threads to run on the system and also increase the pressure
on the VM subsystem for higher order allocations.
diff --git a/arch/arc/include/asm/thread_info.h b/arch/arc/include/asm/thread_info.h
index 9f9dd021501c..a7358d1225a6 100644
--- a/arch/arc/include/asm/thread_info.h
+++ b/arch/arc/include/asm/thread_info.h
@@ -15,7 +15,7 @@
#include <asm/page.h>
-#ifdef CONFIG_16KSTACKS
+#ifdef CONFIG_DEBUG_STACKS
#define THREAD_SIZE_ORDER 1
#else
#define THREAD_SIZE_ORDER 0
--
2.34.1