[PATCH v2 03/23] powerpc/pseries/cmm: remove cmm_balloon_compaction_init()

David Hildenbrand (Red Hat) posted 23 patches 3 weeks, 4 days ago
There is a newer version of this series
[PATCH v2 03/23] powerpc/pseries/cmm: remove cmm_balloon_compaction_init()
Posted by David Hildenbrand (Red Hat) 3 weeks, 4 days ago
Now that there is not a lot of logic left, let's just inline setting up
the migration function.

To avoid #ifdef in the caller we can instead use IS_ENABLED() and make
the compiler happy by only providing the function declaration.

Now that the function is gone, drop the "out_balloon_compaction" label.
Note that before commit 68f2736a8583 ("mm: Convert all PageMovable users
to movable_operations") we actually had to undo something, now not anymore.

Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
---
 arch/powerpc/platforms/pseries/cmm.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c
index 4cbbe2ee58aba..9a6efbc80d2ad 100644
--- a/arch/powerpc/platforms/pseries/cmm.c
+++ b/arch/powerpc/platforms/pseries/cmm.c
@@ -548,15 +548,9 @@ static int cmm_migratepage(struct balloon_dev_info *b_dev_info,
 
 	return 0;
 }
-
-static void cmm_balloon_compaction_init(void)
-{
-	b_dev_info.migratepage = cmm_migratepage;
-}
 #else /* CONFIG_BALLOON_COMPACTION */
-static void cmm_balloon_compaction_init(void)
-{
-}
+int cmm_migratepage(struct balloon_dev_info *b_dev_info, struct page *newpage,
+		    struct page *page, enum migrate_mode mode);
 #endif /* CONFIG_BALLOON_COMPACTION */
 
 /**
@@ -573,11 +567,12 @@ static int cmm_init(void)
 		return -EOPNOTSUPP;
 
 	balloon_devinfo_init(&b_dev_info);
-	cmm_balloon_compaction_init();
+	if (IS_ENABLED(CONFIG_BALLOON_COMPACTION))
+		b_dev_info.migratepage = cmm_migratepage;
 
 	rc = register_oom_notifier(&cmm_oom_nb);
 	if (rc < 0)
-		goto out_balloon_compaction;
+		return rc;
 
 	if ((rc = register_reboot_notifier(&cmm_reboot_nb)))
 		goto out_oom_notifier;
@@ -606,7 +601,6 @@ static int cmm_init(void)
 	unregister_reboot_notifier(&cmm_reboot_nb);
 out_oom_notifier:
 	unregister_oom_notifier(&cmm_oom_nb);
-out_balloon_compaction:
 	return rc;
 }
 
-- 
2.52.0
Re: [PATCH v2 03/23] powerpc/pseries/cmm: remove cmm_balloon_compaction_init()
Posted by Lorenzo Stoakes 3 weeks, 4 days ago
On Thu, Jan 15, 2026 at 10:19:53AM +0100, David Hildenbrand (Red Hat) wrote:
> Now that there is not a lot of logic left, let's just inline setting up
> the migration function.
>
> To avoid #ifdef in the caller we can instead use IS_ENABLED() and make
> the compiler happy by only providing the function declaration.
>
> Now that the function is gone, drop the "out_balloon_compaction" label.
> Note that before commit 68f2736a8583 ("mm: Convert all PageMovable users
> to movable_operations") we actually had to undo something, now not anymore.
>
> Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>

Seems reasonable so:

Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

> ---
>  arch/powerpc/platforms/pseries/cmm.c | 16 +++++-----------
>  1 file changed, 5 insertions(+), 11 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c
> index 4cbbe2ee58aba..9a6efbc80d2ad 100644
> --- a/arch/powerpc/platforms/pseries/cmm.c
> +++ b/arch/powerpc/platforms/pseries/cmm.c
> @@ -548,15 +548,9 @@ static int cmm_migratepage(struct balloon_dev_info *b_dev_info,
>
>  	return 0;
>  }
> -
> -static void cmm_balloon_compaction_init(void)
> -{
> -	b_dev_info.migratepage = cmm_migratepage;
> -}
>  #else /* CONFIG_BALLOON_COMPACTION */
> -static void cmm_balloon_compaction_init(void)
> -{
> -}
> +int cmm_migratepage(struct balloon_dev_info *b_dev_info, struct page *newpage,
> +		    struct page *page, enum migrate_mode mode);
>  #endif /* CONFIG_BALLOON_COMPACTION */
>
>  /**
> @@ -573,11 +567,12 @@ static int cmm_init(void)
>  		return -EOPNOTSUPP;
>
>  	balloon_devinfo_init(&b_dev_info);
> -	cmm_balloon_compaction_init();
> +	if (IS_ENABLED(CONFIG_BALLOON_COMPACTION))
> +		b_dev_info.migratepage = cmm_migratepage;
>
>  	rc = register_oom_notifier(&cmm_oom_nb);
>  	if (rc < 0)
> -		goto out_balloon_compaction;
> +		return rc;
>
>  	if ((rc = register_reboot_notifier(&cmm_reboot_nb)))
>  		goto out_oom_notifier;
> @@ -606,7 +601,6 @@ static int cmm_init(void)
>  	unregister_reboot_notifier(&cmm_reboot_nb);
>  out_oom_notifier:
>  	unregister_oom_notifier(&cmm_oom_nb);
> -out_balloon_compaction:

So silly, I assume before there was more that happened here?

>  	return rc;
>  }
>
> --
> 2.52.0
>
Re: [PATCH v2 03/23] powerpc/pseries/cmm: remove cmm_balloon_compaction_init()
Posted by David Hildenbrand (Red Hat) 2 weeks, 6 days ago
>> @@ -573,11 +567,12 @@ static int cmm_init(void)
>>   		return -EOPNOTSUPP;
>>
>>   	balloon_devinfo_init(&b_dev_info);
>> -	cmm_balloon_compaction_init();
>> +	if (IS_ENABLED(CONFIG_BALLOON_COMPACTION))
>> +		b_dev_info.migratepage = cmm_migratepage;
>>
>>   	rc = register_oom_notifier(&cmm_oom_nb);
>>   	if (rc < 0)
>> -		goto out_balloon_compaction;
>> +		return rc;
>>
>>   	if ((rc = register_reboot_notifier(&cmm_reboot_nb)))
>>   		goto out_oom_notifier;
>> @@ -606,7 +601,6 @@ static int cmm_init(void)
>>   	unregister_reboot_notifier(&cmm_reboot_nb);
>>   out_oom_notifier:
>>   	unregister_oom_notifier(&cmm_oom_nb);
>> -out_balloon_compaction:
> 
> So silly, I assume before there was more that happened here?

Right, I commented that above in the patch description.

Thanks!

-- 
Cheers

David