[bug] __meminit breaks cpu hotplug

[bug] __meminit breaks cpu hotplug

[Ravikiran G Thirumalai]

Recent __meminit additions broke cpu hotplug when the kernel is configured 
with  HOTPLUG_CPU but not HOTPLUG_MEMORY.   
Although __meminit replaced __devinit functions many places, all those functions
looked like they should have been marked with __cpuinit to begin with.  That
is the reason I have changed the below to __cpuinit.  I leave it to Matt if he
wants to use __devinit here instead. (Depending on where he sees __meminit
would be used.)

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>

Index: linux-2.6.16-rc1/include/linux/init.h
===================================================================
--- linux-2.6.16-rc1.orig/include/linux/init.h	2006-01-17 14:12:16.000000000 -0800
+++ linux-2.6.16-rc1/include/linux/init.h	2006-01-20 12:24:44.000000000 -0800
@@ -247,10 +247,10 @@ void __init parse_early_param(void);
 #define __memexit
 #define __memexitdata
 #else
-#define __meminit	__init
-#define __meminitdata __initdata
-#define __memexit __exit
-#define __memexitdata	__exitdata
+#define __meminit	__cpuinit
+#define __meminitdata __cpuinitdata
+#define __memexit __cpuexit
+#define __memexitdata	__cpuexitdata
 #endif
 
 /* Functions marked as __devexit may be discarded at kernel link time, depending

Re: [bug] __meminit breaks cpu hotplug

[Andrew Morton]

Ravikiran G Thirumalai <kiran@scalex86.org> wrote:
>
> Recent __meminit additions broke cpu hotplug when the kernel is configured 
> with  HOTPLUG_CPU but not HOTPLUG_MEMORY.   
> Although __meminit replaced __devinit functions many places, all those functions
> looked like they should have been marked with __cpuinit to begin with.  That
> is the reason I have changed the below to __cpuinit.  I leave it to Matt if he
> wants to use __devinit here instead. (Depending on where he sees __meminit
> would be used.)
> 
> Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
> Signed-off-by: Shai Fultheim <shai@scalex86.org>
> 
> Index: linux-2.6.16-rc1/include/linux/init.h
> ===================================================================
> --- linux-2.6.16-rc1.orig/include/linux/init.h	2006-01-17 14:12:16.000000000 -0800
> +++ linux-2.6.16-rc1/include/linux/init.h	2006-01-20 12:24:44.000000000 -0800
> @@ -247,10 +247,10 @@ void __init parse_early_param(void);
>  #define __memexit
>  #define __memexitdata
>  #else
> -#define __meminit	__init
> -#define __meminitdata __initdata
> -#define __memexit __exit
> -#define __memexitdata	__exitdata
> +#define __meminit	__cpuinit
> +#define __meminitdata __cpuinitdata
> +#define __memexit __cpuexit
> +#define __memexitdata	__cpuexitdata

This looks wrong.  The __meminit and __cpuinit definitions we have now are
OK, aren't they?  Surely the problem is that some functions/variables are
incorrectly tagged?

If some function is needed by both HOTPLUG_CPU and HOTPLUG_MEMORY then
we're rather messed up - I guess it'll need to be put inside #if
defined(..) || defined(..) and put into plain old .text.

Re: [bug] __meminit breaks cpu hotplug

[Ravikiran G Thirumalai]

On Fri, Jan 20, 2006 at 04:55:21PM -0800, Andrew Morton wrote:
> Ravikiran G Thirumalai <kiran@scalex86.org> wrote:
> > -#define __meminitdata __initdata
> > -#define __memexit __exit
> > -#define __memexitdata	__exitdata
> > +#define __meminit	__cpuinit
> > +#define __meminitdata __cpuinitdata
> > +#define __memexit __cpuexit
> > +#define __memexitdata	__cpuexitdata
> 
> This looks wrong.  The __meminit and __cpuinit definitions we have now are
> OK, aren't they?  Surely the problem is that some functions/variables are
> incorrectly tagged?

I hit the bug on pageset_cpuup_callback, which is obviously __cpuinit, but
has been marked __meminit.  Yeah .. bad patch duh! 

For some reason I thought all other functions marked with __meminit looked 
like __cpuinit candidates....while just pageset_cpuup_callback should be
changed to __cpuinit 


Index: linux-2.6.16-rc1/mm/page_alloc.c
===================================================================
--- linux-2.6.16-rc1.orig/mm/page_alloc.c	2006-01-17 14:12:17.000000000 -0800
+++ linux-2.6.16-rc1/mm/page_alloc.c	2006-01-20 17:21:03.000000000 -0800
@@ -1923,7 +1923,7 @@ static inline void free_zone_pagesets(in
 	}
 }
 
-static int __meminit pageset_cpuup_callback(struct notifier_block *nfb,
+static int __cpuinit pageset_cpuup_callback(struct notifier_block *nfb,
 		unsigned long action,
 		void *hcpu)
 {

Re: [bug] __meminit breaks cpu hotplug

[Ashok Raj]

On Fri, Jan 20, 2006 at 05:27:09PM -0800, Ravikiran G Thirumalai wrote:
> 
> 
>    I hit the bug on pageset_cpuup_callback, which is obviously __cpuinit,
>    but
>    has been marked __meminit.  Yeah .. bad patch duh!
> 
>    For  some  reason  I thought all other functions marked with __meminit
>    looked
>    like  __cpuinit candidates....while just pageset_cpuup_callback should
>    be
>    changed to __cpuinit
> 

Sorry i missed this while posting the other patch. There are other functions 
called by process_zones() from withing pageset_cpuup_callback() that
are also marked __meminit. I sent a patch just now to cover that.

but as i mentioned i still have trouble getting cpuup to work right.
cpu_down() seems to work ok so far.

-- 
Cheers,
Ashok Raj
- Open Source Technology Center