From: Rusty Russell

Ingo Molnar wrote:
> * Rusty Russell wrote:
>
>> On Friday 24 October 2008 01:20:25 Ingo Molnar wrote:
>>> Thomas has started a -tip cross-build test, and there's massive
>>> cross-build failures as well due to the cpumask changes:

>> Yes. linux-next reported the same thing. I've backed out various
>> arch changes for this reason.
>>
>>> it seems to me that this commit is massively borked:
>>>
>>> 4a792c2: cpumask: make CONFIG_NR_CPUS always valid

>> Yep. This is the big one I dropped. There are a few others; Mike is
>> just porting the changes across to your tree now.

>
> guys. I already spent hours integrating the "latest" of this stuff today
> and established baseline quality for it on x86. I've dropped 4a792c2 and
> pushed out a new tip/cpus4096-v2, please send append-only patches for
> the rest of the changes.
>
> Ingo


Here are the only changes I could find from Rusty's last patches that
apply to tip/cpus4096-v2.

* Fix NR_CPUS reference in arch/powerpc/platforms/cell/spu_base.c

* modify arch/x86/Kconfig so CONFIG_NR_CPUS is always defined. Also it
does not prompt if MAXSMP is set.

* change include/linux/threads.h so CONFIG_NR_CPUS is defined for those
arch's that do not define it.

Signed-of-by: Rusty Russell
Signed-of-by: Mike Travis
---
Note I haven't been able test anything on this branch, patches or not.
(Everything that has SMP set hangs during startup. I've tried a number
of approaches to creating a source tree but all fail.)
---
arch/powerpc/platforms/cell/spu_base.c | 9 ++++++---
arch/x86/Kconfig | 2 +-
include/linux/threads.h | 16 ++++++++--------
3 files changed, 15 insertions(+), 12 deletions(-)

--- linux-2.6-cpus4096-v2.orig/arch/powerpc/platforms/cell/spu_base.c
+++ linux-2.6-cpus4096-v2/arch/powerpc/platforms/cell/spu_base.c
@@ -111,10 +111,13 @@ void spu_flush_all_slbs(struct mm_struct
*/
static inline void mm_needs_global_tlbie(struct mm_struct *mm)
{
- int nr = (NR_CPUS > 1) ? NR_CPUS : NR_CPUS + 1;
-
/* Global TLBIE broadcast required with SPEs. */
- __cpus_setall(&mm->cpu_vm_mask, nr);
+ if (NR_CPUS > 1)
+ cpumask_setall(&mm->cpu_vm_mask);
+ else {
+ cpumask_set_cpu(0, &mm->cpu_vm_mask);
+ cpumask_set_cpu(1, &mm->cpu_vm_mask);
+ }
}

void spu_associate_mm(struct spu *spu, struct mm_struct *mm)
--- linux-2.6-cpus4096-v2.orig/arch/x86/Kconfig
+++ linux-2.6-cpus4096-v2/arch/x86/Kconfig
@@ -585,9 +585,9 @@ config MAXSMP
If unsure, say N.

config NR_CPUS
- depends on SMP
int "Maximum number of CPUs" if SMP && !MAXSMP
range 2 512 if SMP && !MAXSMP
+ default "1" if !SMP
default "4096" if MAXSMP
default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
default "8"
--- linux-2.6-cpus4096-v2.orig/include/linux/threads.h
+++ linux-2.6-cpus4096-v2/include/linux/threads.h
@@ -8,17 +8,17 @@
*/

/*
- * Maximum supported processors that can run under SMP. This value is
- * set via configure setting. The maximum is equal to the size of the
- * bitmasks used on that platform, i.e. 32 or 64. Setting this smaller
- * saves quite a bit of memory.
+ * Maximum supported processors. Setting this smaller saves quite a
+ * bit of memory. Use nr_cpu_ids instead of this except for static bitmaps.
*/
-#ifdef CONFIG_SMP
-#define NR_CPUS CONFIG_NR_CPUS
-#else
-#define NR_CPUS 1
+#ifndef CONFIG_NR_CPUS
+/* FIXME: This should be fixed in the arch's Kconfig */
+#define CONFIG_NR_CPUS 1
#endif

+/* Places which use this should consider cpumask_var_t. */
+#define NR_CPUS CONFIG_NR_CPUS
+
#define MIN_THREADS_LEFT_FOR_ROOT 4

/*
--
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