diff mbox series

[v4,2/4] mm/page_reporting: Export reporting order as module parameter

Message ID 20210625014710.42954-3-gshan@redhat.com (mailing list archive)
State New
Headers show
Series mm/page_reporting: Make page reporting work on arm64 with 64KB page size | expand

Commit Message

Gavin Shan June 25, 2021, 1:47 a.m. UTC 
The macro PAGE_REPORTING_MIN_ORDER is defined as the page reporting
threshold. It can't be adjusted at runtime.

This introduces a variable (@page_reporting_order) to replace the
marcro (PAGE_REPORTING_MIN_ORDER). MAX_ORDER is assigned to it initially,
meaning the page reporting is disabled. It will be specified by driver
if valid one is provided. Otherwise, it will fall back to @pageblock_order.
It's also exported so that the page reporting order can be adjusted at
runtime.

Suggested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
 mm/page_reporting.c                             | 9 +++++++--
 mm/page_reporting.h                             | 5 ++---
 3 files changed, 15 insertions(+), 5 deletions(-)

Comments

Alexander Duyck June 25, 2021, 1:14 a.m. UTC | #1 
On Thu, Jun 24, 2021 at 4:46 PM Gavin Shan <gshan@redhat.com> wrote:
>
> The macro PAGE_REPORTING_MIN_ORDER is defined as the page reporting
> threshold. It can't be adjusted at runtime.
>
> This introduces a variable (@page_reporting_order) to replace the
> marcro (PAGE_REPORTING_MIN_ORDER). MAX_ORDER is assigned to it initially,
> meaning the page reporting is disabled. It will be specified by driver
> if valid one is provided. Otherwise, it will fall back to @pageblock_order.
> It's also exported so that the page reporting order can be adjusted at
> runtime.
>
> Suggested-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>

So this patch looks like it is technically broken. We need a line in
page_reporting_register that will overwrite the value with
pageblock_order if it is less than page_reporting_order.

> ---
>  Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
>  mm/page_reporting.c                             | 9 +++++++--
>  mm/page_reporting.h                             | 5 ++---
>  3 files changed, 15 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index cb89dbdedc46..566c4b9af3cd 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -3566,6 +3566,12 @@
>                         off: turn off poisoning (default)
>                         on: turn on poisoning
>
> +       page_reporting.page_reporting_order=
> +                       [KNL] Minimal page reporting order
> +                       Format: <integer>
> +                       Adjust the minimal page reporting order. The page
> +                       reporting is disabled when it exceeds (MAX_ORDER-1).
> +
>         panic=          [KNL] Kernel behaviour on panic: delay <timeout>
>                         timeout > 0: seconds before rebooting
>                         timeout = 0: wait forever
> diff --git a/mm/page_reporting.c b/mm/page_reporting.c
> index df9c5054e1b4..34bf4d26c2c4 100644
> --- a/mm/page_reporting.c
> +++ b/mm/page_reporting.c
> @@ -4,12 +4,17 @@
>  #include <linux/page_reporting.h>
>  #include <linux/gfp.h>
>  #include <linux/export.h>
> +#include <linux/module.h>
>  #include <linux/delay.h>
>  #include <linux/scatterlist.h>
>
>  #include "page_reporting.h"
>  #include "internal.h"
>
> +unsigned int page_reporting_order = MAX_ORDER;
> +module_param(page_reporting_order, uint, 0644);
> +MODULE_PARM_DESC(page_reporting_order, "Set page reporting order");
> +
>  #define PAGE_REPORTING_DELAY   (2 * HZ)
>  static struct page_reporting_dev_info __rcu *pr_dev_info __read_mostly;
>
> @@ -229,7 +234,7 @@ page_reporting_process_zone(struct page_reporting_dev_info *prdev,
>
>         /* Generate minimum watermark to be able to guarantee progress */
>         watermark = low_wmark_pages(zone) +
> -                   (PAGE_REPORTING_CAPACITY << PAGE_REPORTING_MIN_ORDER);
> +                   (PAGE_REPORTING_CAPACITY << page_reporting_order);
>
>         /*
>          * Cancel request if insufficient free memory or if we failed
> @@ -239,7 +244,7 @@ page_reporting_process_zone(struct page_reporting_dev_info *prdev,
>                 return err;
>
>         /* Process each free list starting from lowest order/mt */
> -       for (order = PAGE_REPORTING_MIN_ORDER; order < MAX_ORDER; order++) {
> +       for (order = page_reporting_order; order < MAX_ORDER; order++) {
>                 for (mt = 0; mt < MIGRATE_TYPES; mt++) {
>                         /* We do not pull pages from the isolate free list */
>                         if (is_migrate_isolate(mt))
> diff --git a/mm/page_reporting.h b/mm/page_reporting.h
> index 2c385dd4ddbd..c51dbc228b94 100644
> --- a/mm/page_reporting.h
> +++ b/mm/page_reporting.h
> @@ -10,10 +10,9 @@
>  #include <linux/pgtable.h>
>  #include <linux/scatterlist.h>
>
> -#define PAGE_REPORTING_MIN_ORDER       pageblock_order
> -
>  #ifdef CONFIG_PAGE_REPORTING
>  DECLARE_STATIC_KEY_FALSE(page_reporting_enabled);
> +extern unsigned int page_reporting_order;
>  void __page_reporting_notify(void);
>
>  static inline bool page_reported(struct page *page)
> @@ -38,7 +37,7 @@ static inline void page_reporting_notify_free(unsigned int order)
>                 return;
>
>         /* Determine if we have crossed reporting threshold */
> -       if (order < PAGE_REPORTING_MIN_ORDER)
> +       if (order < page_reporting_order)
>                 return;
>
>         /* This will add a few cycles, but should be called infrequently */
> --
> 2.23.0
>
Gavin Shan June 25, 2021, 3:58 a.m. UTC | #2 
On 6/25/21 11:14 AM, Alexander Duyck wrote:
> On Thu, Jun 24, 2021 at 4:46 PM Gavin Shan <gshan@redhat.com> wrote:
>>
>> The macro PAGE_REPORTING_MIN_ORDER is defined as the page reporting
>> threshold. It can't be adjusted at runtime.
>>
>> This introduces a variable (@page_reporting_order) to replace the
>> marcro (PAGE_REPORTING_MIN_ORDER). MAX_ORDER is assigned to it initially,
>> meaning the page reporting is disabled. It will be specified by driver
>> if valid one is provided. Otherwise, it will fall back to @pageblock_order.
>> It's also exported so that the page reporting order can be adjusted at
>> runtime.
>>
>> Suggested-by: David Hildenbrand <david@redhat.com>
>> Signed-off-by: Gavin Shan <gshan@redhat.com>
>> Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
> 
> So this patch looks like it is technically broken. We need a line in
> page_reporting_register that will overwrite the value with
> pageblock_order if it is less than page_reporting_order.
> 

Yes, but it's not broken after next (PATCH[3/4]) is applied.
However, It's still worthy to be fixed, to be "git bisect"
friendly. I'll update in v5.

Thanks,
Gavin

>> ---
>>   Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
>>   mm/page_reporting.c                             | 9 +++++++--
>>   mm/page_reporting.h                             | 5 ++---
>>   3 files changed, 15 insertions(+), 5 deletions(-)
>>
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index cb89dbdedc46..566c4b9af3cd 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -3566,6 +3566,12 @@
>>                          off: turn off poisoning (default)
>>                          on: turn on poisoning
>>
>> +       page_reporting.page_reporting_order=
>> +                       [KNL] Minimal page reporting order
>> +                       Format: <integer>
>> +                       Adjust the minimal page reporting order. The page
>> +                       reporting is disabled when it exceeds (MAX_ORDER-1).
>> +
>>          panic=          [KNL] Kernel behaviour on panic: delay <timeout>
>>                          timeout > 0: seconds before rebooting
>>                          timeout = 0: wait forever
>> diff --git a/mm/page_reporting.c b/mm/page_reporting.c
>> index df9c5054e1b4..34bf4d26c2c4 100644
>> --- a/mm/page_reporting.c
>> +++ b/mm/page_reporting.c
>> @@ -4,12 +4,17 @@
>>   #include <linux/page_reporting.h>
>>   #include <linux/gfp.h>
>>   #include <linux/export.h>
>> +#include <linux/module.h>
>>   #include <linux/delay.h>
>>   #include <linux/scatterlist.h>
>>
>>   #include "page_reporting.h"
>>   #include "internal.h"
>>
>> +unsigned int page_reporting_order = MAX_ORDER;
>> +module_param(page_reporting_order, uint, 0644);
>> +MODULE_PARM_DESC(page_reporting_order, "Set page reporting order");
>> +
>>   #define PAGE_REPORTING_DELAY   (2 * HZ)
>>   static struct page_reporting_dev_info __rcu *pr_dev_info __read_mostly;
>>
>> @@ -229,7 +234,7 @@ page_reporting_process_zone(struct page_reporting_dev_info *prdev,
>>
>>          /* Generate minimum watermark to be able to guarantee progress */
>>          watermark = low_wmark_pages(zone) +
>> -                   (PAGE_REPORTING_CAPACITY << PAGE_REPORTING_MIN_ORDER);
>> +                   (PAGE_REPORTING_CAPACITY << page_reporting_order);
>>
>>          /*
>>           * Cancel request if insufficient free memory or if we failed
>> @@ -239,7 +244,7 @@ page_reporting_process_zone(struct page_reporting_dev_info *prdev,
>>                  return err;
>>
>>          /* Process each free list starting from lowest order/mt */
>> -       for (order = PAGE_REPORTING_MIN_ORDER; order < MAX_ORDER; order++) {
>> +       for (order = page_reporting_order; order < MAX_ORDER; order++) {
>>                  for (mt = 0; mt < MIGRATE_TYPES; mt++) {
>>                          /* We do not pull pages from the isolate free list */
>>                          if (is_migrate_isolate(mt))
>> diff --git a/mm/page_reporting.h b/mm/page_reporting.h
>> index 2c385dd4ddbd..c51dbc228b94 100644
>> --- a/mm/page_reporting.h
>> +++ b/mm/page_reporting.h
>> @@ -10,10 +10,9 @@
>>   #include <linux/pgtable.h>
>>   #include <linux/scatterlist.h>
>>
>> -#define PAGE_REPORTING_MIN_ORDER       pageblock_order
>> -
>>   #ifdef CONFIG_PAGE_REPORTING
>>   DECLARE_STATIC_KEY_FALSE(page_reporting_enabled);
>> +extern unsigned int page_reporting_order;
>>   void __page_reporting_notify(void);
>>
>>   static inline bool page_reported(struct page *page)
>> @@ -38,7 +37,7 @@ static inline void page_reporting_notify_free(unsigned int order)
>>                  return;
>>
>>          /* Determine if we have crossed reporting threshold */
>> -       if (order < PAGE_REPORTING_MIN_ORDER)
>> +       if (order < page_reporting_order)
>>                  return;
>>
>>          /* This will add a few cycles, but should be called infrequently */
>> --
>> 2.23.0
>>
>
Michael S. Tsirkin June 25, 2021, 5:53 a.m. UTC | #3 
On Fri, Jun 25, 2021 at 09:47:08AM +0800, Gavin Shan wrote:
> The macro PAGE_REPORTING_MIN_ORDER is defined as the page reporting
> threshold. It can't be adjusted at runtime.
> 
> This introduces a variable (@page_reporting_order) to replace the
> marcro (PAGE_REPORTING_MIN_ORDER). MAX_ORDER is assigned to it initially,
> meaning the page reporting is disabled. It will be specified by driver
> if valid one is provided. Otherwise, it will fall back to @pageblock_order.
> It's also exported so that the page reporting order can be adjusted at
> runtime.
> 
> Suggested-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
> ---
>  Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
>  mm/page_reporting.c                             | 9 +++++++--
>  mm/page_reporting.h                             | 5 ++---
>  3 files changed, 15 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index cb89dbdedc46..566c4b9af3cd 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -3566,6 +3566,12 @@
>  			off: turn off poisoning (default)
>  			on: turn on poisoning
>  
> +	page_reporting.page_reporting_order=
> +			[KNL] Minimal page reporting order
> +			Format: <integer>
> +			Adjust the minimal page reporting order. The page
> +			reporting is disabled when it exceeds (MAX_ORDER-1).

Which the admin knows how? Run grep in the kernel source?

> +
>  	panic=		[KNL] Kernel behaviour on panic: delay <timeout>
>  			timeout > 0: seconds before rebooting
>  			timeout = 0: wait forever
> diff --git a/mm/page_reporting.c b/mm/page_reporting.c
> index df9c5054e1b4..34bf4d26c2c4 100644
> --- a/mm/page_reporting.c
> +++ b/mm/page_reporting.c
> @@ -4,12 +4,17 @@
>  #include <linux/page_reporting.h>
>  #include <linux/gfp.h>
>  #include <linux/export.h>
> +#include <linux/module.h>
>  #include <linux/delay.h>
>  #include <linux/scatterlist.h>
>  
>  #include "page_reporting.h"
>  #include "internal.h"
>  
> +unsigned int page_reporting_order = MAX_ORDER;
> +module_param(page_reporting_order, uint, 0644);
> +MODULE_PARM_DESC(page_reporting_order, "Set page reporting order");
> +
>  #define PAGE_REPORTING_DELAY	(2 * HZ)
>  static struct page_reporting_dev_info __rcu *pr_dev_info __read_mostly;
>  
> @@ -229,7 +234,7 @@ page_reporting_process_zone(struct page_reporting_dev_info *prdev,
>  
>  	/* Generate minimum watermark to be able to guarantee progress */
>  	watermark = low_wmark_pages(zone) +
> -		    (PAGE_REPORTING_CAPACITY << PAGE_REPORTING_MIN_ORDER);
> +		    (PAGE_REPORTING_CAPACITY << page_reporting_order);


Looks like this makes it easy to trigger undefined behaviour. Just use
any value > 31.

>  
>  	/*
>  	 * Cancel request if insufficient free memory or if we failed
> @@ -239,7 +244,7 @@ page_reporting_process_zone(struct page_reporting_dev_info *prdev,
>  		return err;
>  
>  	/* Process each free list starting from lowest order/mt */
> -	for (order = PAGE_REPORTING_MIN_ORDER; order < MAX_ORDER; order++) {
> +	for (order = page_reporting_order; order < MAX_ORDER; order++) {
>  		for (mt = 0; mt < MIGRATE_TYPES; mt++) {
>  			/* We do not pull pages from the isolate free list */
>  			if (is_migrate_isolate(mt))
> diff --git a/mm/page_reporting.h b/mm/page_reporting.h
> index 2c385dd4ddbd..c51dbc228b94 100644
> --- a/mm/page_reporting.h
> +++ b/mm/page_reporting.h
> @@ -10,10 +10,9 @@
>  #include <linux/pgtable.h>
>  #include <linux/scatterlist.h>
>  
> -#define PAGE_REPORTING_MIN_ORDER	pageblock_order
> -
>  #ifdef CONFIG_PAGE_REPORTING
>  DECLARE_STATIC_KEY_FALSE(page_reporting_enabled);
> +extern unsigned int page_reporting_order;
>  void __page_reporting_notify(void);
>  
>  static inline bool page_reported(struct page *page)
> @@ -38,7 +37,7 @@ static inline void page_reporting_notify_free(unsigned int order)
>  		return;
>  
>  	/* Determine if we have crossed reporting threshold */
> -	if (order < PAGE_REPORTING_MIN_ORDER)
> +	if (order < page_reporting_order)
>  		return;
>  
>  	/* This will add a few cycles, but should be called infrequently */
> -- 
> 2.23.0
Gavin Shan June 25, 2021, 6:08 a.m. UTC | #4 
On 6/25/21 3:53 PM, Michael S. Tsirkin wrote:
> On Fri, Jun 25, 2021 at 09:47:08AM +0800, Gavin Shan wrote:
>> The macro PAGE_REPORTING_MIN_ORDER is defined as the page reporting
>> threshold. It can't be adjusted at runtime.
>>
>> This introduces a variable (@page_reporting_order) to replace the
>> marcro (PAGE_REPORTING_MIN_ORDER). MAX_ORDER is assigned to it initially,
>> meaning the page reporting is disabled. It will be specified by driver
>> if valid one is provided. Otherwise, it will fall back to @pageblock_order.
>> It's also exported so that the page reporting order can be adjusted at
>> runtime.
>>
>> Suggested-by: David Hildenbrand <david@redhat.com>
>> Signed-off-by: Gavin Shan <gshan@redhat.com>
>> Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
>> ---
>>   Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
>>   mm/page_reporting.c                             | 9 +++++++--
>>   mm/page_reporting.h                             | 5 ++---
>>   3 files changed, 15 insertions(+), 5 deletions(-)
>>
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index cb89dbdedc46..566c4b9af3cd 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -3566,6 +3566,12 @@
>>   			off: turn off poisoning (default)
>>   			on: turn on poisoning
>>   
>> +	page_reporting.page_reporting_order=
>> +			[KNL] Minimal page reporting order
>> +			Format: <integer>
>> +			Adjust the minimal page reporting order. The page
>> +			reporting is disabled when it exceeds (MAX_ORDER-1).
> 
> Which the admin knows how? Run grep in the kernel source?
> 

Well, I guess it's fine as it's used for debugging purpose. I guess
it's mostly used by developers. Also, the value can be changed by
the module parameter in "/sys/module/page_reporting" either.

>> +
>>   	panic=		[KNL] Kernel behaviour on panic: delay <timeout>
>>   			timeout > 0: seconds before rebooting
>>   			timeout = 0: wait forever
>> diff --git a/mm/page_reporting.c b/mm/page_reporting.c
>> index df9c5054e1b4..34bf4d26c2c4 100644
>> --- a/mm/page_reporting.c
>> +++ b/mm/page_reporting.c
>> @@ -4,12 +4,17 @@
>>   #include <linux/page_reporting.h>
>>   #include <linux/gfp.h>
>>   #include <linux/export.h>
>> +#include <linux/module.h>
>>   #include <linux/delay.h>
>>   #include <linux/scatterlist.h>
>>   
>>   #include "page_reporting.h"
>>   #include "internal.h"
>>   
>> +unsigned int page_reporting_order = MAX_ORDER;
>> +module_param(page_reporting_order, uint, 0644);
>> +MODULE_PARM_DESC(page_reporting_order, "Set page reporting order");
>> +
>>   #define PAGE_REPORTING_DELAY	(2 * HZ)
>>   static struct page_reporting_dev_info __rcu *pr_dev_info __read_mostly;
>>   
>> @@ -229,7 +234,7 @@ page_reporting_process_zone(struct page_reporting_dev_info *prdev,
>>   
>>   	/* Generate minimum watermark to be able to guarantee progress */
>>   	watermark = low_wmark_pages(zone) +
>> -		    (PAGE_REPORTING_CAPACITY << PAGE_REPORTING_MIN_ORDER);
>> +		    (PAGE_REPORTING_CAPACITY << page_reporting_order);
> 
> 
> Looks like this makes it easy to trigger undefined behaviour. Just use
> any value > 31.
> 

This function won't be run if page_reporting_order is more than (MAX_ORDER-1).

>>   
>>   	/*
>>   	 * Cancel request if insufficient free memory or if we failed
>> @@ -239,7 +244,7 @@ page_reporting_process_zone(struct page_reporting_dev_info *prdev,
>>   		return err;
>>   
>>   	/* Process each free list starting from lowest order/mt */
>> -	for (order = PAGE_REPORTING_MIN_ORDER; order < MAX_ORDER; order++) {
>> +	for (order = page_reporting_order; order < MAX_ORDER; order++) {
>>   		for (mt = 0; mt < MIGRATE_TYPES; mt++) {
>>   			/* We do not pull pages from the isolate free list */
>>   			if (is_migrate_isolate(mt))
>> diff --git a/mm/page_reporting.h b/mm/page_reporting.h
>> index 2c385dd4ddbd..c51dbc228b94 100644
>> --- a/mm/page_reporting.h
>> +++ b/mm/page_reporting.h
>> @@ -10,10 +10,9 @@
>>   #include <linux/pgtable.h>
>>   #include <linux/scatterlist.h>
>>   
>> -#define PAGE_REPORTING_MIN_ORDER	pageblock_order
>> -
>>   #ifdef CONFIG_PAGE_REPORTING
>>   DECLARE_STATIC_KEY_FALSE(page_reporting_enabled);
>> +extern unsigned int page_reporting_order;
>>   void __page_reporting_notify(void);
>>   
>>   static inline bool page_reported(struct page *page)
>> @@ -38,7 +37,7 @@ static inline void page_reporting_notify_free(unsigned int order)
>>   		return;
>>   
>>   	/* Determine if we have crossed reporting threshold */
>> -	if (order < PAGE_REPORTING_MIN_ORDER)
>> +	if (order < page_reporting_order)
>>   		return;
>>   
>>   	/* This will add a few cycles, but should be called infrequently */
>> -- 
>> 2.23.0
> 

Thanks,
Gavin
diff mbox series

Patch

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index cb89dbdedc46..566c4b9af3cd 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3566,6 +3566,12 @@ 
 			off: turn off poisoning (default)
 			on: turn on poisoning
 
+	page_reporting.page_reporting_order=
+			[KNL] Minimal page reporting order
+			Format: <integer>
+			Adjust the minimal page reporting order. The page
+			reporting is disabled when it exceeds (MAX_ORDER-1).
+
 	panic=		[KNL] Kernel behaviour on panic: delay <timeout>
 			timeout > 0: seconds before rebooting
 			timeout = 0: wait forever
diff --git a/mm/page_reporting.c b/mm/page_reporting.c
index df9c5054e1b4..34bf4d26c2c4 100644
--- a/mm/page_reporting.c
+++ b/mm/page_reporting.c
@@ -4,12 +4,17 @@ 
 #include <linux/page_reporting.h>
 #include <linux/gfp.h>
 #include <linux/export.h>
+#include <linux/module.h>
 #include <linux/delay.h>
 #include <linux/scatterlist.h>
 
 #include "page_reporting.h"
 #include "internal.h"
 
+unsigned int page_reporting_order = MAX_ORDER;
+module_param(page_reporting_order, uint, 0644);
+MODULE_PARM_DESC(page_reporting_order, "Set page reporting order");
+
 #define PAGE_REPORTING_DELAY	(2 * HZ)
 static struct page_reporting_dev_info __rcu *pr_dev_info __read_mostly;
 
@@ -229,7 +234,7 @@  page_reporting_process_zone(struct page_reporting_dev_info *prdev,
 
 	/* Generate minimum watermark to be able to guarantee progress */
 	watermark = low_wmark_pages(zone) +
-		    (PAGE_REPORTING_CAPACITY << PAGE_REPORTING_MIN_ORDER);
+		    (PAGE_REPORTING_CAPACITY << page_reporting_order);
 
 	/*
 	 * Cancel request if insufficient free memory or if we failed
@@ -239,7 +244,7 @@  page_reporting_process_zone(struct page_reporting_dev_info *prdev,
 		return err;
 
 	/* Process each free list starting from lowest order/mt */
-	for (order = PAGE_REPORTING_MIN_ORDER; order < MAX_ORDER; order++) {
+	for (order = page_reporting_order; order < MAX_ORDER; order++) {
 		for (mt = 0; mt < MIGRATE_TYPES; mt++) {
 			/* We do not pull pages from the isolate free list */
 			if (is_migrate_isolate(mt))
diff --git a/mm/page_reporting.h b/mm/page_reporting.h
index 2c385dd4ddbd..c51dbc228b94 100644
--- a/mm/page_reporting.h
+++ b/mm/page_reporting.h
@@ -10,10 +10,9 @@ 
 #include <linux/pgtable.h>
 #include <linux/scatterlist.h>
 
-#define PAGE_REPORTING_MIN_ORDER	pageblock_order
-
 #ifdef CONFIG_PAGE_REPORTING
 DECLARE_STATIC_KEY_FALSE(page_reporting_enabled);
+extern unsigned int page_reporting_order;
 void __page_reporting_notify(void);
 
 static inline bool page_reported(struct page *page)
@@ -38,7 +37,7 @@  static inline void page_reporting_notify_free(unsigned int order)
 		return;
 
 	/* Determine if we have crossed reporting threshold */
-	if (order < PAGE_REPORTING_MIN_ORDER)
+	if (order < page_reporting_order)
 		return;
 
 	/* This will add a few cycles, but should be called infrequently */