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[PATCH mm-unstable v3 3/5] mm/khugepaged: define KHUGEPAGED_MAX_PTES_LIMIT as HPAGE_PMD_NR - 1

Nico Pache posted 5 patches 3 weeks, 5 days ago
There is a newer version of this series
[PATCH mm-unstable v3 3/5] mm/khugepaged: define KHUGEPAGED_MAX_PTES_LIMIT as HPAGE_PMD_NR - 1
Posted by Nico Pache 3 weeks, 5 days ago 
The value (HPAGE_PMD_NR - 1) is used often in the khugepaged code to
signify the limit of the max_ptes_* values. Add a define for this to
increase code readability and reuse.

Acked-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Nico Pache <npache@redhat.com>
---
 mm/khugepaged.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index d3bdec4ec61b..db77ab5b315e 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -89,6 +89,7 @@ static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait);
  *
  * Note that these are only respected if collapse was initiated by khugepaged.
  */
+#define KHUGEPAGED_MAX_PTES_LIMIT (HPAGE_PMD_NR - 1)
 unsigned int khugepaged_max_ptes_none __read_mostly;
 static unsigned int khugepaged_max_ptes_swap __read_mostly;
 static unsigned int khugepaged_max_ptes_shared __read_mostly;
@@ -259,7 +260,7 @@ static ssize_t max_ptes_none_store(struct kobject *kobj,
 	unsigned long max_ptes_none;
 
 	err = kstrtoul(buf, 10, &max_ptes_none);
-	if (err || max_ptes_none > HPAGE_PMD_NR - 1)
+	if (err || max_ptes_none > KHUGEPAGED_MAX_PTES_LIMIT)
 		return -EINVAL;
 
 	khugepaged_max_ptes_none = max_ptes_none;
@@ -284,7 +285,7 @@ static ssize_t max_ptes_swap_store(struct kobject *kobj,
 	unsigned long max_ptes_swap;
 
 	err  = kstrtoul(buf, 10, &max_ptes_swap);
-	if (err || max_ptes_swap > HPAGE_PMD_NR - 1)
+	if (err || max_ptes_swap > KHUGEPAGED_MAX_PTES_LIMIT)
 		return -EINVAL;
 
 	khugepaged_max_ptes_swap = max_ptes_swap;
@@ -310,7 +311,7 @@ static ssize_t max_ptes_shared_store(struct kobject *kobj,
 	unsigned long max_ptes_shared;
 
 	err  = kstrtoul(buf, 10, &max_ptes_shared);
-	if (err || max_ptes_shared > HPAGE_PMD_NR - 1)
+	if (err || max_ptes_shared > KHUGEPAGED_MAX_PTES_LIMIT)
 		return -EINVAL;
 
 	khugepaged_max_ptes_shared = max_ptes_shared;
@@ -382,7 +383,7 @@ int __init khugepaged_init(void)
 		return -ENOMEM;
 
 	khugepaged_pages_to_scan = HPAGE_PMD_NR * 8;
-	khugepaged_max_ptes_none = HPAGE_PMD_NR - 1;
+	khugepaged_max_ptes_none = KHUGEPAGED_MAX_PTES_LIMIT;
 	khugepaged_max_ptes_swap = HPAGE_PMD_NR / 8;
 	khugepaged_max_ptes_shared = HPAGE_PMD_NR / 2;
 
-- 
2.53.0
Re: [PATCH mm-unstable v3 3/5] mm/khugepaged: define KHUGEPAGED_MAX_PTES_LIMIT as HPAGE_PMD_NR - 1
Posted by Lorenzo Stoakes (Oracle) 3 weeks, 1 day ago 
On Wed, Mar 11, 2026 at 03:13:13PM -0600, Nico Pache wrote:
> The value (HPAGE_PMD_NR - 1) is used often in the khugepaged code to
> signify the limit of the max_ptes_* values. Add a define for this to
> increase code readability and reuse.
>
> Acked-by: Pedro Falcato <pfalcato@suse.de>
> Acked-by: David Hildenbrand (Arm) <david@kernel.org>
> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> Reviewed-by: Zi Yan <ziy@nvidia.com>
> Signed-off-by: Nico Pache <npache@redhat.com>

Hm didn't I suggest this? Or actually I can't remember :P

Anyway LGTM, so:

Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>

> ---
>  mm/khugepaged.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index d3bdec4ec61b..db77ab5b315e 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -89,6 +89,7 @@ static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait);
>   *
>   * Note that these are only respected if collapse was initiated by khugepaged.
>   */
> +#define KHUGEPAGED_MAX_PTES_LIMIT (HPAGE_PMD_NR - 1)
>  unsigned int khugepaged_max_ptes_none __read_mostly;
>  static unsigned int khugepaged_max_ptes_swap __read_mostly;
>  static unsigned int khugepaged_max_ptes_shared __read_mostly;
> @@ -259,7 +260,7 @@ static ssize_t max_ptes_none_store(struct kobject *kobj,
>  	unsigned long max_ptes_none;
>
>  	err = kstrtoul(buf, 10, &max_ptes_none);
> -	if (err || max_ptes_none > HPAGE_PMD_NR - 1)
> +	if (err || max_ptes_none > KHUGEPAGED_MAX_PTES_LIMIT)
>  		return -EINVAL;
>
>  	khugepaged_max_ptes_none = max_ptes_none;
> @@ -284,7 +285,7 @@ static ssize_t max_ptes_swap_store(struct kobject *kobj,
>  	unsigned long max_ptes_swap;
>
>  	err  = kstrtoul(buf, 10, &max_ptes_swap);
> -	if (err || max_ptes_swap > HPAGE_PMD_NR - 1)
> +	if (err || max_ptes_swap > KHUGEPAGED_MAX_PTES_LIMIT)
>  		return -EINVAL;
>
>  	khugepaged_max_ptes_swap = max_ptes_swap;
> @@ -310,7 +311,7 @@ static ssize_t max_ptes_shared_store(struct kobject *kobj,
>  	unsigned long max_ptes_shared;
>
>  	err  = kstrtoul(buf, 10, &max_ptes_shared);
> -	if (err || max_ptes_shared > HPAGE_PMD_NR - 1)
> +	if (err || max_ptes_shared > KHUGEPAGED_MAX_PTES_LIMIT)
>  		return -EINVAL;
>
>  	khugepaged_max_ptes_shared = max_ptes_shared;
> @@ -382,7 +383,7 @@ int __init khugepaged_init(void)
>  		return -ENOMEM;
>
>  	khugepaged_pages_to_scan = HPAGE_PMD_NR * 8;
> -	khugepaged_max_ptes_none = HPAGE_PMD_NR - 1;
> +	khugepaged_max_ptes_none = KHUGEPAGED_MAX_PTES_LIMIT;
>  	khugepaged_max_ptes_swap = HPAGE_PMD_NR / 8;
>  	khugepaged_max_ptes_shared = HPAGE_PMD_NR / 2;
>
> --
> 2.53.0
>
Re: [PATCH mm-unstable v3 3/5] mm/khugepaged: define KHUGEPAGED_MAX_PTES_LIMIT as HPAGE_PMD_NR - 1
Posted by Nico Pache 2 weeks, 6 days ago 

On 3/16/26 12:18 PM, Lorenzo Stoakes (Oracle) wrote:
> On Wed, Mar 11, 2026 at 03:13:13PM -0600, Nico Pache wrote:
>> The value (HPAGE_PMD_NR - 1) is used often in the khugepaged code to
>> signify the limit of the max_ptes_* values. Add a define for this to
>> increase code readability and reuse.
>>
>> Acked-by: Pedro Falcato <pfalcato@suse.de>
>> Acked-by: David Hildenbrand (Arm) <david@kernel.org>
>> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
>> Reviewed-by: Zi Yan <ziy@nvidia.com>
>> Signed-off-by: Nico Pache <npache@redhat.com>
> 
> Hm didn't I suggest this? Or actually I can't remember :P

I think you suggested most of these patches ;P Ill make sure to add your SB tag
on the followups!

> 
> Anyway LGTM, so:
> 
> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>

Thank you!

> 
>> ---
>>  mm/khugepaged.c | 9 +++++----
>>  1 file changed, 5 insertions(+), 4 deletions(-)
>>
>> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
>> index d3bdec4ec61b..db77ab5b315e 100644
>> --- a/mm/khugepaged.c
>> +++ b/mm/khugepaged.c
>> @@ -89,6 +89,7 @@ static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait);
>>   *
>>   * Note that these are only respected if collapse was initiated by khugepaged.
>>   */
>> +#define KHUGEPAGED_MAX_PTES_LIMIT (HPAGE_PMD_NR - 1)
>>  unsigned int khugepaged_max_ptes_none __read_mostly;
>>  static unsigned int khugepaged_max_ptes_swap __read_mostly;
>>  static unsigned int khugepaged_max_ptes_shared __read_mostly;
>> @@ -259,7 +260,7 @@ static ssize_t max_ptes_none_store(struct kobject *kobj,
>>  	unsigned long max_ptes_none;
>>
>>  	err = kstrtoul(buf, 10, &max_ptes_none);
>> -	if (err || max_ptes_none > HPAGE_PMD_NR - 1)
>> +	if (err || max_ptes_none > KHUGEPAGED_MAX_PTES_LIMIT)
>>  		return -EINVAL;
>>
>>  	khugepaged_max_ptes_none = max_ptes_none;
>> @@ -284,7 +285,7 @@ static ssize_t max_ptes_swap_store(struct kobject *kobj,
>>  	unsigned long max_ptes_swap;
>>
>>  	err  = kstrtoul(buf, 10, &max_ptes_swap);
>> -	if (err || max_ptes_swap > HPAGE_PMD_NR - 1)
>> +	if (err || max_ptes_swap > KHUGEPAGED_MAX_PTES_LIMIT)
>>  		return -EINVAL;
>>
>>  	khugepaged_max_ptes_swap = max_ptes_swap;
>> @@ -310,7 +311,7 @@ static ssize_t max_ptes_shared_store(struct kobject *kobj,
>>  	unsigned long max_ptes_shared;
>>
>>  	err  = kstrtoul(buf, 10, &max_ptes_shared);
>> -	if (err || max_ptes_shared > HPAGE_PMD_NR - 1)
>> +	if (err || max_ptes_shared > KHUGEPAGED_MAX_PTES_LIMIT)
>>  		return -EINVAL;
>>
>>  	khugepaged_max_ptes_shared = max_ptes_shared;
>> @@ -382,7 +383,7 @@ int __init khugepaged_init(void)
>>  		return -ENOMEM;
>>
>>  	khugepaged_pages_to_scan = HPAGE_PMD_NR * 8;
>> -	khugepaged_max_ptes_none = HPAGE_PMD_NR - 1;
>> +	khugepaged_max_ptes_none = KHUGEPAGED_MAX_PTES_LIMIT;
>>  	khugepaged_max_ptes_swap = HPAGE_PMD_NR / 8;
>>  	khugepaged_max_ptes_shared = HPAGE_PMD_NR / 2;
>>
>> --
>> 2.53.0
>>
>

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