[PATCH] mm: rename CONFIG_PAGE_BLOCK_ORDER to CONFIG_PAGE_BLOCK_ORDER_CEIL.

[PATCH] mm: rename CONFIG_PAGE_BLOCK_ORDER to CONFIG_PAGE_BLOCK_ORDER_CEIL.

[Zi Yan]

The config is in fact an additional upper limit of pageblock_order, so
rename it to avoid confusion.

Fixes: e13e7922d034 ("mm: add CONFIG_PAGE_BLOCK_ORDER to select page block order")
Signed-off-by: Zi Yan <ziy@nvidia.com>
---
 include/linux/mmzone.h          | 14 +++++++-------
 include/linux/pageblock-flags.h |  8 ++++----
 mm/Kconfig                      | 15 ++++++++-------
 3 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 283913d42d7b..523b407e63e8 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -38,19 +38,19 @@
 #define NR_PAGE_ORDERS (MAX_PAGE_ORDER + 1)
 
 /* Defines the order for the number of pages that have a migrate type. */
-#ifndef CONFIG_PAGE_BLOCK_ORDER
-#define PAGE_BLOCK_ORDER MAX_PAGE_ORDER
+#ifndef CONFIG_PAGE_BLOCK_ORDER_CEIL
+#define PAGE_BLOCK_ORDER_CEIL MAX_PAGE_ORDER
 #else
-#define PAGE_BLOCK_ORDER CONFIG_PAGE_BLOCK_ORDER
-#endif /* CONFIG_PAGE_BLOCK_ORDER */
+#define PAGE_BLOCK_ORDER_CEIL CONFIG_PAGE_BLOCK_ORDER_CEIL
+#endif /* CONFIG_PAGE_BLOCK_ORDER_CEIL */
 
 /*
  * The MAX_PAGE_ORDER, which defines the max order of pages to be allocated
- * by the buddy allocator, has to be larger or equal to the PAGE_BLOCK_ORDER,
+ * by the buddy allocator, has to be larger or equal to the PAGE_BLOCK_ORDER_CEIL,
  * which defines the order for the number of pages that can have a migrate type
  */
-#if (PAGE_BLOCK_ORDER > MAX_PAGE_ORDER)
-#error MAX_PAGE_ORDER must be >= PAGE_BLOCK_ORDER
+#if (PAGE_BLOCK_ORDER_CEIL > MAX_PAGE_ORDER)
+#error MAX_PAGE_ORDER must be >= PAGE_BLOCK_ORDER_CEIL
 #endif
 
 /*
diff --git a/include/linux/pageblock-flags.h b/include/linux/pageblock-flags.h
index e73a4292ef02..e7a86cd238c2 100644
--- a/include/linux/pageblock-flags.h
+++ b/include/linux/pageblock-flags.h
@@ -41,18 +41,18 @@ extern unsigned int pageblock_order;
  * Huge pages are a constant size, but don't exceed the maximum allocation
  * granularity.
  */
-#define pageblock_order		MIN_T(unsigned int, HUGETLB_PAGE_ORDER, PAGE_BLOCK_ORDER)
+#define pageblock_order		MIN_T(unsigned int, HUGETLB_PAGE_ORDER, PAGE_BLOCK_ORDER_CEIL)
 
 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
 
 #elif defined(CONFIG_TRANSPARENT_HUGEPAGE)
 
-#define pageblock_order		MIN_T(unsigned int, HPAGE_PMD_ORDER, PAGE_BLOCK_ORDER)
+#define pageblock_order		MIN_T(unsigned int, HPAGE_PMD_ORDER, PAGE_BLOCK_ORDER_CEIL)
 
 #else /* CONFIG_TRANSPARENT_HUGEPAGE */
 
-/* If huge pages are not used, group by PAGE_BLOCK_ORDER */
-#define pageblock_order		PAGE_BLOCK_ORDER
+/* If huge pages are not used, group by PAGE_BLOCK_ORDER_CEIL */
+#define pageblock_order		PAGE_BLOCK_ORDER_CEIL
 
 #endif /* CONFIG_HUGETLB_PAGE */
 
diff --git a/mm/Kconfig b/mm/Kconfig
index eccb2e46ffcb..3b27e644bd1f 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -1017,8 +1017,8 @@ config ARCH_FORCE_MAX_ORDER
 # the default page block order is MAX_PAGE_ORDER (10) as per
 # include/linux/mmzone.h.
 #
-config PAGE_BLOCK_ORDER
-	int "Page Block Order"
+config PAGE_BLOCK_ORDER_CEIL
+	int "Page Block Order Upper Limit"
 	range 1 10 if ARCH_FORCE_MAX_ORDER = 0
 	default 10 if ARCH_FORCE_MAX_ORDER = 0
 	range 1 ARCH_FORCE_MAX_ORDER if ARCH_FORCE_MAX_ORDER != 0
@@ -1026,12 +1026,13 @@ config PAGE_BLOCK_ORDER
 	help
 	  The page block order refers to the power of two number of pages that
 	  are physically contiguous and can have a migrate type associated to
-	  them. The maximum size of the page block order is limited by
-	  ARCH_FORCE_MAX_ORDER.
+	  them. The maximum size of the page block order is at least limited by
+	  ARCH_FORCE_MAX_ORDER/MAX_PAGE_ORDER.
 
-	  This config allows overriding the default page block order when the
-	  page block order is required to be smaller than ARCH_FORCE_MAX_ORDER
-	  or MAX_PAGE_ORDER.
+	  This config adds a new upper limit of default page block
+	  order when the page block order is required to be smaller than
+	  ARCH_FORCE_MAX_ORDER/MAX_PAGE_ORDER or other limits
+	  (see include/linux/pageblock-flags.h for details).
 
 	  Reducing pageblock order can negatively impact THP generation
 	  success rate. If your workloads uses THP heavily, please use this
-- 
2.47.2

Re: [PATCH] mm: rename CONFIG_PAGE_BLOCK_ORDER to CONFIG_PAGE_BLOCK_ORDER_CEIL.

[David Hildenbrand]

On 03.06.25 17:48, Zi Yan wrote:
> The config is in fact an additional upper limit of pageblock_order, so
> rename it to avoid confusion.
> 
> Fixes: e13e7922d034 ("mm: add CONFIG_PAGE_BLOCK_ORDER to select page block order")
> Signed-off-by: Zi Yan <ziy@nvidia.com>
> ---

Acked-by: David Hildenbrand <david@redhat.com>

-- 
Cheers,

David / dhildenb

Re: [PATCH] mm: rename CONFIG_PAGE_BLOCK_ORDER to CONFIG_PAGE_BLOCK_ORDER_CEIL.

[Juan Yescas]

On Tue, Jun 3, 2025 at 8:49 AM Zi Yan <ziy@nvidia.com> wrote:
>
> The config is in fact an additional upper limit of pageblock_order, so
> rename it to avoid confusion.
>
> Fixes: e13e7922d034 ("mm: add CONFIG_PAGE_BLOCK_ORDER to select page block order")
> Signed-off-by: Zi Yan <ziy@nvidia.com>
> ---
>  include/linux/mmzone.h          | 14 +++++++-------
>  include/linux/pageblock-flags.h |  8 ++++----
>  mm/Kconfig                      | 15 ++++++++-------
>  3 files changed, 19 insertions(+), 18 deletions(-)
>
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 283913d42d7b..523b407e63e8 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -38,19 +38,19 @@
>  #define NR_PAGE_ORDERS (MAX_PAGE_ORDER + 1)
>
>  /* Defines the order for the number of pages that have a migrate type. */
> -#ifndef CONFIG_PAGE_BLOCK_ORDER
> -#define PAGE_BLOCK_ORDER MAX_PAGE_ORDER
> +#ifndef CONFIG_PAGE_BLOCK_ORDER_CEIL
> +#define PAGE_BLOCK_ORDER_CEIL MAX_PAGE_ORDER
>  #else
> -#define PAGE_BLOCK_ORDER CONFIG_PAGE_BLOCK_ORDER
> -#endif /* CONFIG_PAGE_BLOCK_ORDER */
> +#define PAGE_BLOCK_ORDER_CEIL CONFIG_PAGE_BLOCK_ORDER_CEIL
> +#endif /* CONFIG_PAGE_BLOCK_ORDER_CEIL */
>
>  /*
>   * The MAX_PAGE_ORDER, which defines the max order of pages to be allocated
> - * by the buddy allocator, has to be larger or equal to the PAGE_BLOCK_ORDER,
> + * by the buddy allocator, has to be larger or equal to the PAGE_BLOCK_ORDER_CEIL,
>   * which defines the order for the number of pages that can have a migrate type
>   */
> -#if (PAGE_BLOCK_ORDER > MAX_PAGE_ORDER)
> -#error MAX_PAGE_ORDER must be >= PAGE_BLOCK_ORDER
> +#if (PAGE_BLOCK_ORDER_CEIL > MAX_PAGE_ORDER)
> +#error MAX_PAGE_ORDER must be >= PAGE_BLOCK_ORDER_CEIL
>  #endif
>
>  /*
> diff --git a/include/linux/pageblock-flags.h b/include/linux/pageblock-flags.h
> index e73a4292ef02..e7a86cd238c2 100644
> --- a/include/linux/pageblock-flags.h
> +++ b/include/linux/pageblock-flags.h
> @@ -41,18 +41,18 @@ extern unsigned int pageblock_order;
>   * Huge pages are a constant size, but don't exceed the maximum allocation
>   * granularity.
>   */
> -#define pageblock_order                MIN_T(unsigned int, HUGETLB_PAGE_ORDER, PAGE_BLOCK_ORDER)
> +#define pageblock_order                MIN_T(unsigned int, HUGETLB_PAGE_ORDER, PAGE_BLOCK_ORDER_CEIL)
>
>  #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
>
>  #elif defined(CONFIG_TRANSPARENT_HUGEPAGE)
>
> -#define pageblock_order                MIN_T(unsigned int, HPAGE_PMD_ORDER, PAGE_BLOCK_ORDER)
> +#define pageblock_order                MIN_T(unsigned int, HPAGE_PMD_ORDER, PAGE_BLOCK_ORDER_CEIL)
>
>  #else /* CONFIG_TRANSPARENT_HUGEPAGE */
>
> -/* If huge pages are not used, group by PAGE_BLOCK_ORDER */
> -#define pageblock_order                PAGE_BLOCK_ORDER
> +/* If huge pages are not used, group by PAGE_BLOCK_ORDER_CEIL */
> +#define pageblock_order                PAGE_BLOCK_ORDER_CEIL
>
>  #endif /* CONFIG_HUGETLB_PAGE */
>
> diff --git a/mm/Kconfig b/mm/Kconfig
> index eccb2e46ffcb..3b27e644bd1f 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -1017,8 +1017,8 @@ config ARCH_FORCE_MAX_ORDER
>  # the default page block order is MAX_PAGE_ORDER (10) as per
>  # include/linux/mmzone.h.
>  #
> -config PAGE_BLOCK_ORDER
> -       int "Page Block Order"
> +config PAGE_BLOCK_ORDER_CEIL
> +       int "Page Block Order Upper Limit"
>         range 1 10 if ARCH_FORCE_MAX_ORDER = 0
>         default 10 if ARCH_FORCE_MAX_ORDER = 0
>         range 1 ARCH_FORCE_MAX_ORDER if ARCH_FORCE_MAX_ORDER != 0
> @@ -1026,12 +1026,13 @@ config PAGE_BLOCK_ORDER
>         help
>           The page block order refers to the power of two number of pages that
>           are physically contiguous and can have a migrate type associated to
> -         them. The maximum size of the page block order is limited by
> -         ARCH_FORCE_MAX_ORDER.
> +         them. The maximum size of the page block order is at least limited by
> +         ARCH_FORCE_MAX_ORDER/MAX_PAGE_ORDER.
>
> -         This config allows overriding the default page block order when the
> -         page block order is required to be smaller than ARCH_FORCE_MAX_ORDER
> -         or MAX_PAGE_ORDER.
> +         This config adds a new upper limit of default page block
> +         order when the page block order is required to be smaller than
> +         ARCH_FORCE_MAX_ORDER/MAX_PAGE_ORDER or other limits
> +         (see include/linux/pageblock-flags.h for details).
>
>           Reducing pageblock order can negatively impact THP generation
>           success rate. If your workloads uses THP heavily, please use this
> --
> 2.47.2

Acked-by: Juan Yescas <jyescas@google.com>

Thanks
Juan
>

Re: [PATCH] mm: rename CONFIG_PAGE_BLOCK_ORDER to CONFIG_PAGE_BLOCK_ORDER_CEIL.

[Anshuman Khandual]

On 6/3/25 21:18, Zi Yan wrote:
> The config is in fact an additional upper limit of pageblock_order, so
> rename it to avoid confusion.

Agreed. This new config has been similar to existing 'pageblock_order'
that might cause confusion. Hence renaming makes sense. But instead of
PAGE_BLOCK_ORDER_CEIL should it be rather PAGE_BLOCK_ORDER_MAX ?

> 
> Fixes: e13e7922d034 ("mm: add CONFIG_PAGE_BLOCK_ORDER to select page block order")

Does it really need a "Fixes: " tag given there is no problem to fix ?

> Signed-off-by: Zi Yan <ziy@nvidia.com>
> ---
>  include/linux/mmzone.h          | 14 +++++++-------
>  include/linux/pageblock-flags.h |  8 ++++----
>  mm/Kconfig                      | 15 ++++++++-------
>  3 files changed, 19 insertions(+), 18 deletions(-)
> 
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 283913d42d7b..523b407e63e8 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -38,19 +38,19 @@
>  #define NR_PAGE_ORDERS (MAX_PAGE_ORDER + 1)
>  
>  /* Defines the order for the number of pages that have a migrate type. */
> -#ifndef CONFIG_PAGE_BLOCK_ORDER
> -#define PAGE_BLOCK_ORDER MAX_PAGE_ORDER
> +#ifndef CONFIG_PAGE_BLOCK_ORDER_CEIL
> +#define PAGE_BLOCK_ORDER_CEIL MAX_PAGE_ORDER
>  #else
> -#define PAGE_BLOCK_ORDER CONFIG_PAGE_BLOCK_ORDER
> -#endif /* CONFIG_PAGE_BLOCK_ORDER */
> +#define PAGE_BLOCK_ORDER_CEIL CONFIG_PAGE_BLOCK_ORDER_CEIL
> +#endif /* CONFIG_PAGE_BLOCK_ORDER_CEIL */
>  
>  /*
>   * The MAX_PAGE_ORDER, which defines the max order of pages to be allocated
> - * by the buddy allocator, has to be larger or equal to the PAGE_BLOCK_ORDER,
> + * by the buddy allocator, has to be larger or equal to the PAGE_BLOCK_ORDER_CEIL,
>   * which defines the order for the number of pages that can have a migrate type
>   */
> -#if (PAGE_BLOCK_ORDER > MAX_PAGE_ORDER)
> -#error MAX_PAGE_ORDER must be >= PAGE_BLOCK_ORDER
> +#if (PAGE_BLOCK_ORDER_CEIL > MAX_PAGE_ORDER)
> +#error MAX_PAGE_ORDER must be >= PAGE_BLOCK_ORDER_CEIL
>  #endif
>  
>  /*
> diff --git a/include/linux/pageblock-flags.h b/include/linux/pageblock-flags.h
> index e73a4292ef02..e7a86cd238c2 100644
> --- a/include/linux/pageblock-flags.h
> +++ b/include/linux/pageblock-flags.h
> @@ -41,18 +41,18 @@ extern unsigned int pageblock_order;
>   * Huge pages are a constant size, but don't exceed the maximum allocation
>   * granularity.
>   */
> -#define pageblock_order		MIN_T(unsigned int, HUGETLB_PAGE_ORDER, PAGE_BLOCK_ORDER)
> +#define pageblock_order		MIN_T(unsigned int, HUGETLB_PAGE_ORDER, PAGE_BLOCK_ORDER_CEIL)
>  
>  #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
>  
>  #elif defined(CONFIG_TRANSPARENT_HUGEPAGE)
>  
> -#define pageblock_order		MIN_T(unsigned int, HPAGE_PMD_ORDER, PAGE_BLOCK_ORDER)
> +#define pageblock_order		MIN_T(unsigned int, HPAGE_PMD_ORDER, PAGE_BLOCK_ORDER_CEIL)
>  
>  #else /* CONFIG_TRANSPARENT_HUGEPAGE */
>  
> -/* If huge pages are not used, group by PAGE_BLOCK_ORDER */
> -#define pageblock_order		PAGE_BLOCK_ORDER
> +/* If huge pages are not used, group by PAGE_BLOCK_ORDER_CEIL */
> +#define pageblock_order		PAGE_BLOCK_ORDER_CEIL
>  
>  #endif /* CONFIG_HUGETLB_PAGE */
>  
> diff --git a/mm/Kconfig b/mm/Kconfig
> index eccb2e46ffcb..3b27e644bd1f 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -1017,8 +1017,8 @@ config ARCH_FORCE_MAX_ORDER
>  # the default page block order is MAX_PAGE_ORDER (10) as per
>  # include/linux/mmzone.h.
>  #
> -config PAGE_BLOCK_ORDER
> -	int "Page Block Order"
> +config PAGE_BLOCK_ORDER_CEIL
> +	int "Page Block Order Upper Limit"
>  	range 1 10 if ARCH_FORCE_MAX_ORDER = 0
>  	default 10 if ARCH_FORCE_MAX_ORDER = 0
>  	range 1 ARCH_FORCE_MAX_ORDER if ARCH_FORCE_MAX_ORDER != 0
> @@ -1026,12 +1026,13 @@ config PAGE_BLOCK_ORDER
>  	help
>  	  The page block order refers to the power of two number of pages that
>  	  are physically contiguous and can have a migrate type associated to
> -	  them. The maximum size of the page block order is limited by
> -	  ARCH_FORCE_MAX_ORDER.
> +	  them. The maximum size of the page block order is at least limited by
> +	  ARCH_FORCE_MAX_ORDER/MAX_PAGE_ORDER.
>  
> -	  This config allows overriding the default page block order when the
> -	  page block order is required to be smaller than ARCH_FORCE_MAX_ORDER
> -	  or MAX_PAGE_ORDER.
> +	  This config adds a new upper limit of default page block
> +	  order when the page block order is required to be smaller than
> +	  ARCH_FORCE_MAX_ORDER/MAX_PAGE_ORDER or other limits
> +	  (see include/linux/pageblock-flags.h for details).
>  
>  	  Reducing pageblock order can negatively impact THP generation
>  	  success rate. If your workloads uses THP heavily, please use this

Re: [PATCH] mm: rename CONFIG_PAGE_BLOCK_ORDER to CONFIG_PAGE_BLOCK_ORDER_CEIL.

[Oscar Salvador]

On Tue, Jun 03, 2025 at 11:48:43AM -0400, Zi Yan wrote:
> The config is in fact an additional upper limit of pageblock_order, so
> rename it to avoid confusion.
> 
> Fixes: e13e7922d034 ("mm: add CONFIG_PAGE_BLOCK_ORDER to select page block order")
> Signed-off-by: Zi Yan <ziy@nvidia.com>

Reviewed-by: Oscar Salvador <osalvador@suse.de>


-- 
Oscar Salvador
SUSE Labs

Re: [PATCH] mm: rename CONFIG_PAGE_BLOCK_ORDER to CONFIG_PAGE_BLOCK_ORDER_CEIL.

[Zi Yan]

On 4 Jun 2025, at 0:36, Anshuman Khandual wrote:

> On 6/3/25 21:18, Zi Yan wrote:
>> The config is in fact an additional upper limit of pageblock_order, so
>> rename it to avoid confusion.
>
> Agreed. This new config has been similar to existing 'pageblock_order'
> that might cause confusion. Hence renaming makes sense. But instead of
> PAGE_BLOCK_ORDER_CEIL should it be rather PAGE_BLOCK_ORDER_MAX ?

Or PAGE_BLOCK_MAX_ORDER?

>
>>
>> Fixes: e13e7922d034 ("mm: add CONFIG_PAGE_BLOCK_ORDER to select page block order")
>
> Does it really need a "Fixes: " tag given there is no problem to fix ?

I have no strong opinion on this one.

If you like a different name, I can send v2 and drop Fixes.

--
Best Regards,
Yan, Zi

Re: [PATCH] mm: rename CONFIG_PAGE_BLOCK_ORDER to CONFIG_PAGE_BLOCK_ORDER_CEIL.

[David Hildenbrand]

On 04.06.25 15:26, Zi Yan wrote:
> On 4 Jun 2025, at 0:36, Anshuman Khandual wrote:
> 
>> On 6/3/25 21:18, Zi Yan wrote:
>>> The config is in fact an additional upper limit of pageblock_order, so
>>> rename it to avoid confusion.
>>
>> Agreed. This new config has been similar to existing 'pageblock_order'
>> that might cause confusion. Hence renaming makes sense. But instead of
>> PAGE_BLOCK_ORDER_CEIL should it be rather PAGE_BLOCK_ORDER_MAX ?
> 
> Or PAGE_BLOCK_MAX_ORDER?

Would also work for me.

> 
>>
>>>
>>> Fixes: e13e7922d034 ("mm: add CONFIG_PAGE_BLOCK_ORDER to select page block order")
>>
>> Does it really need a "Fixes: " tag given there is no problem to fix ?
> 
> I have no strong opinion on this one.

Probably we want this to go into this release. No need for a Fixes: I 
assume.

-- 
Cheers,

David / dhildenb

Re: [PATCH] mm: rename CONFIG_PAGE_BLOCK_ORDER to CONFIG_PAGE_BLOCK_ORDER_CEIL.

[Zi Yan]

On 4 Jun 2025, at 9:31, David Hildenbrand wrote:

> On 04.06.25 15:26, Zi Yan wrote:
>> On 4 Jun 2025, at 0:36, Anshuman Khandual wrote:
>>
>>> On 6/3/25 21:18, Zi Yan wrote:
>>>> The config is in fact an additional upper limit of pageblock_order, so
>>>> rename it to avoid confusion.
>>>
>>> Agreed. This new config has been similar to existing 'pageblock_order'
>>> that might cause confusion. Hence renaming makes sense. But instead of
>>> PAGE_BLOCK_ORDER_CEIL should it be rather PAGE_BLOCK_ORDER_MAX ?
>>
>> Or PAGE_BLOCK_MAX_ORDER?
>
> Would also work for me.
>
>>
>>>
>>>>
>>>> Fixes: e13e7922d034 ("mm: add CONFIG_PAGE_BLOCK_ORDER to select page block order")
>>>
>>> Does it really need a "Fixes: " tag given there is no problem to fix ?
>>
>> I have no strong opinion on this one.
>
> Probably we want this to go into this release. No need for a Fixes: I assume.

OK. I will send v2 later today, so that Anshuman has a chance to reply to my
new name.

V2 will has following changes:
1. the new name: PAGE_BLOCK_MAX_ORDER,
2. add the missing PAGE_BLOCK_ORDER rename in mm/mm_init.c[1]
3. drop the Fixes.

[1] https://lore.kernel.org/linux-mm/202506042058.XgvABCE0-lkp@intel.com/

--
Best Regards,
Yan, Zi