The commit 32cc0b7c9d50 ("powerpc: add pte_free_defer() for pgtables
sharing page") introduced the use of PageActive flag to page table
fragments tracking, so the ptdesc->__page_flags is not unused, so
correct the wrong comment.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
 include/linux/mm_types.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index a7223ba3ea1e..5ea77969daae 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -419,7 +419,7 @@ FOLIO_MATCH(compound_head, _head_2a);
 
 /**
  * struct ptdesc -    Memory descriptor for page tables.
- * @__page_flags:     Same as page flags. Unused for page tables.
+ * @__page_flags:     Same as page flags. Powerpc only.
  * @pt_rcu_head:      For freeing page table pages.
  * @pt_list:          List of used page tables. Used for s390 and x86.
  * @_pt_pad_1:        Padding that aliases with page's compound head.
-- 
2.30.2

On Mon, Mar 04, 2024 at 07:07:18PM +0800, Qi Zheng wrote:
> The commit 32cc0b7c9d50 ("powerpc: add pte_free_defer() for pgtables
> sharing page") introduced the use of PageActive flag to page table
> fragments tracking, so the ptdesc->__page_flags is not unused, so
> correct the wrong comment.

Thanks for catching this!

In regards to naming, we're trying to prefix unused variables with
__underscores so I'd prefer to see the __ eliminated from the
ptdesc->page_flags field here as well. This doesn't warrant a fix
as it is already in 6.9-rc1, but is something to keep in
mind for the future. Aside from that, LGTM.

Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
> ---
>  include/linux/mm_types.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index a7223ba3ea1e..5ea77969daae 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -419,7 +419,7 @@ FOLIO_MATCH(compound_head, _head_2a);
>  
>  /**
>   * struct ptdesc -    Memory descriptor for page tables.
> - * @__page_flags:     Same as page flags. Unused for page tables.
> + * @__page_flags:     Same as page flags. Powerpc only.
>   * @pt_rcu_head:      For freeing page table pages.
>   * @pt_list:          List of used page tables. Used for s390 and x86.
>   * @_pt_pad_1:        Padding that aliases with page's compound head.
> -- 
> 2.30.2
>

On 2024/3/27 03:12, Vishal Moola wrote:
> On Mon, Mar 04, 2024 at 07:07:18PM +0800, Qi Zheng wrote:
>> The commit 32cc0b7c9d50 ("powerpc: add pte_free_defer() for pgtables
>> sharing page") introduced the use of PageActive flag to page table
>> fragments tracking, so the ptdesc->__page_flags is not unused, so
>> correct the wrong comment.
> 
> Thanks for catching this!
> 
> In regards to naming, we're trying to prefix unused variables with
> __underscores so I'd prefer to see the __ eliminated from the
> ptdesc->page_flags field here as well. This doesn't warrant a fix
> as it is already in 6.9-rc1, but is something to keep in
> mind for the future. 

Got it.

> Aside from that, LGTM.
> 
> Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>

Thanks!

>> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
>> ---
>>   include/linux/mm_types.h | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
>> index a7223ba3ea1e..5ea77969daae 100644
>> --- a/include/linux/mm_types.h
>> +++ b/include/linux/mm_types.h
>> @@ -419,7 +419,7 @@ FOLIO_MATCH(compound_head, _head_2a);
>>   
>>   /**
>>    * struct ptdesc -    Memory descriptor for page tables.
>> - * @__page_flags:     Same as page flags. Unused for page tables.
>> + * @__page_flags:     Same as page flags. Powerpc only.
>>    * @pt_rcu_head:      For freeing page table pages.
>>    * @pt_list:          List of used page tables. Used for s390 and x86.
>>    * @_pt_pad_1:        Padding that aliases with page's compound head.
>> -- 
>> 2.30.2
>>