smp: Remove CONFIG_SMP_IDLETHREAD_STACKSIZE

Summary:
- The CONFIG_SMP_IDLETHREAD_STACKSIZE was introduced to optimize
  the idle stack size for other than CPU0
- However, there are no big differences between the idle stacks.
- This commit removes the config to simplify the kernel code

Impact:
- All SMP configurations

Testing:
- Tested with ostest with the following configs
- spresense:smp, spresense:rndis_smp
- esp32-devkitc:smp (QEMU), maix-bit:smp (QEMU)
- sabre-6quad:smp (QEMU), sabre-6quad:netnsh_smp (QEMU)
- raspberrypi-pico:smp, sim:smp (x86_64)

Signed-off-by: Masayuki Ishikawa <asayuki.Ishikawa@jp.sony.com>

Documentation/platforms/xtensa/esp32/boards/esp32-devkitc/index.rst

@@ -163,7 +163,6 @@ additional settings:
 SMP is enabled::
 
   CONFIG_SMP=y
-  CONFIG_SMP_IDLETHREAD_STACKSIZE=3072
   CONFIG_SMP_NCPUS=2
   CONFIG_SPINLOCK=y
 
@@ -182,7 +181,6 @@ architecture ports to assure a correct implementation of the OS.  The default
 version is for a single CPU but can be modified for an SMP test by adding::
 
   CONFIG_SMP=y
-  CONFIG_SMP_IDLETHREAD_STACKSIZE=2048
   CONFIG_SMP_NCPUS=2
   CONFIG_SPINLOCK=y
 

Documentation/platforms/xtensa/esp32/index.rst

@@ -258,7 +258,6 @@ in :menuselection:`RTOS Features --> Tasks and Scheduling`, with::
     CONFIG_SPINLOCK=y
     CONFIG_SMP=y
     CONFIG_SMP_NCPUS=2
-    CONFIG_SMP_IDLETHREAD_STACKSIZE=3072
 
 Debug Tip:  During debug session, OpenOCD may mysteriously switch from one
 CPU to another.  This behavior can be eliminated by uncommenting one of the

arch/arm/src/armv7-a/smp.h

@@ -40,7 +40,7 @@
 
 #define SMP_STACK_ALIGNMENT  8
 #define SMP_STACK_MASK       7
-#define SMP_STACK_SIZE       ((CONFIG_SMP_IDLETHREAD_STACKSIZE + 7) & ~7)
+#define SMP_STACK_SIZE       ((CONFIG_IDLETHREAD_STACKSIZE + 7) & ~7)
 #define SMP_STACK_WORDS      (SMP_STACK_SIZE >> 2)
 
 /****************************************************************************

arch/risc-v/src/k210/k210_cpuidlestack.c

@@ -35,7 +35,7 @@
 #ifdef CONFIG_SMP
 
 #define SMP_STACK_MASK       7
-#define SMP_STACK_SIZE       ((CONFIG_SMP_IDLETHREAD_STACKSIZE + 7) & ~7)
+#define SMP_STACK_SIZE       ((CONFIG_IDLETHREAD_STACKSIZE + 7) & ~7)
 #define STACK_ISALIGNED(a)   ((uintptr_t)(a) & ~SMP_STACK_MASK)
 
 #if CONFIG_SMP_NCPUS > 1

arch/sim/src/sim/up_cpuidlestack.c

@@ -72,7 +72,7 @@
  *   - tcb:         The TCB of new CPU IDLE task
  *   - stack_size:  The requested stack size for the IDLE task.  At least
  *                  this much must be allocated.  This should be
- *                  CONFIG_SMP_IDLETHREAD_STACKSIZE.
+ *                  CONFIG_IDLETHREAD_STACKSIZE.
  *
  ****************************************************************************/
 

arch/xtensa/src/esp32/esp32_cpuidlestack.c

@@ -82,7 +82,7 @@ uint32_t g_cpu1_idlestack[CPU1_IDLETHREAD_STACKWORDS]
  *   - tcb:         The TCB of new CPU IDLE task
  *   - stack_size:  The requested stack size for the IDLE task.  At least
  *                  this much must be allocated.  This should be
- *                  CONFIG_SMP_IDLETHREAD_STACKSIZE.
+ *                  CONFIG_IDLETHREAD_STACKSIZE.
  *
  ****************************************************************************/
 

arch/xtensa/src/esp32/esp32_smp.h

@@ -35,13 +35,13 @@
 
 /* An IDLE thread stack size for CPU0 must be defined */
 
-#if !defined(CONFIG_SMP_IDLETHREAD_STACKSIZE)
+#if !defined(CONFIG_IDLETHREAD_STACKSIZE)
-#  error CONFIG_SMP_IDLETHREAD_STACKSIZE is not defined
+#  error CONFIG_IDLETHREAD_STACKSIZE is not defined
-#elif CONFIG_SMP_IDLETHREAD_STACKSIZE < 16
+#elif CONFIG_IDLETHREAD_STACKSIZE < 16
-#  error CONFIG_SMP_IDLETHREAD_STACKSIZE is to small
+#  error CONFIG_IDLETHREAD_STACKSIZE is to small
 #endif
 
-#define CPU1_IDLETHREAD_STACKSIZE ((CONFIG_SMP_IDLETHREAD_STACKSIZE + 15) & ~15)
+#define CPU1_IDLETHREAD_STACKSIZE ((CONFIG_IDLETHREAD_STACKSIZE + 15) & ~15)
 #define CPU1_IDLETHREAD_STACKWORDS (CPU1_IDLETHREAD_STACKSIZE >> 2)
 
 /****************************************************************************

boards/arm/cxd56xx/spresense/configs/rndis_smp/defconfig

@@ -137,7 +137,6 @@ CONFIG_SMARTFS_ALIGNED_ACCESS=y
 CONFIG_SMARTFS_MAXNAMLEN=30
 CONFIG_SMARTFS_MULTI_ROOT_DIRS=y
 CONFIG_SMP=y
-CONFIG_SMP_IDLETHREAD_STACKSIZE=1024
 CONFIG_SMP_NCPUS=2
 CONFIG_SPI=y
 CONFIG_SPRESENSE_EXTENSION=y

boards/arm/imx6/sabre-6quad/README.txt

@@ -711,7 +711,6 @@ be enabled with the following configuration settings:
     CONFIG_SPINLOCK=y
     CONFIG_SMP=y
     CONFIG_SMP_NCPUS=4
-    CONFIG_SMP_IDLETHREAD_STACKSIZE=2048
 
 Open Issues:
 

boards/arm/imx6/sabre-6quad/configs/netnsh_smp/defconfig

@@ -75,7 +75,6 @@ CONFIG_RR_INTERVAL=200
 CONFIG_SCHED_HPWORK=y
 CONFIG_SCHED_LPWORK=y
 CONFIG_SMP=y
-CONFIG_SMP_IDLETHREAD_STACKSIZE=1024
 CONFIG_STACK_COLORATION=y
 CONFIG_START_DAY=8
 CONFIG_START_MONTH=3

boards/sim/sim/sim/README.txt

@@ -315,7 +315,6 @@ SMP
     +CONFIG_SPINLOCK=y
     +CONFIG_SMP=y
     +CONFIG_SMP_NCPUS=2
-    +CONFIG_SMP_IDLETHREAD_STACKSIZE=2048
 
   You also must enable near-realtime-performance otherwise even long timeouts
   will expire before a CPU thread even has a chance to execute.

boards/xtensa/esp32/esp32-devkitc/configs/smp/defconfig

@@ -41,7 +41,6 @@ CONFIG_READLINE_CMD_HISTORY=y
 CONFIG_RR_INTERVAL=200
 CONFIG_SDCLONE_DISABLE=y
 CONFIG_SMP=y
-CONFIG_SMP_IDLETHREAD_STACKSIZE=3072
 CONFIG_SMP_NCPUS=2
 CONFIG_SPI=y
 CONFIG_START_DAY=6

include/nuttx/arch.h

@@ -1871,7 +1871,7 @@ int up_cpu_index(void);
  *   - tcb:         The TCB of new CPU IDLE task
  *   - stack_size:  The requested stack size for the IDLE task.  At least
  *                  this much must be allocated.  This should be
- *                  CONFIG_SMP_IDLETHREAD_STACKSIZE.
+ *                  CONFIG_IDLETHREAD_STACKSIZE.
  *
  ****************************************************************************/
 

sched/Kconfig

@@ -291,15 +291,6 @@ config SMP_NCPUS
 		SMP configuration.  However, running the SMP logic in a single CPU
 		configuration is useful during certain testing.
 
-config SMP_IDLETHREAD_STACKSIZE
-	int "CPU IDLE stack size"
-	default DEFAULT_TASK_STACKSIZE
-	---help---
-		Each CPU will have its own IDLE task.  System initialization occurs
-		on CPU0 and uses CONFIG_IDLETHREAD_STACKSIZE which will probably be
-		larger than is generally needed.  This setting provides the stack
-		size for the IDLE task on CPUS 1 through (CONFIG_SMP_NCPUS-1).
-
 endif # SMP
 
 choice

sched/init/nx_smpstart.c

@@ -120,7 +120,7 @@ int nx_smp_start(void)
       FAR struct tcb_s *tcb = current_task(cpu);
       DEBUGASSERT(tcb != NULL);
 
-      ret = up_cpu_idlestack(cpu, tcb, CONFIG_SMP_IDLETHREAD_STACKSIZE);
+      ret = up_cpu_idlestack(cpu, tcb, CONFIG_IDLETHREAD_STACKSIZE);
       if (ret < 0)
         {
           serr("ERROR: Failed to allocate stack for CPU%d\n", cpu);