diff mbox series

[v3,2/4] mm/page_reporting: Export reporting order as module parameter

Message ID 20210623023418.350616-3-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 23, 2021, 2:34 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). 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>
---
 Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
 mm/page_reporting.c                             | 8 ++++++--
 mm/page_reporting.h                             | 5 ++---
 3 files changed, 14 insertions(+), 5 deletions(-)

Comments

Alexander H Duyck June 24, 2021, 1:55 p.m. UTC | #1
On Tue, Jun 22, 2021 at 5:34 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). 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>
> ---
>  Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
>  mm/page_reporting.c                             | 8 ++++++--
>  mm/page_reporting.h                             | 5 ++---
>  3 files changed, 14 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).
> +

Based on the issue found by Stephen I think we may need to tweak this
a bit. I think we may want to just default this value to MAX_ORDER. We
can override this value at registration time with the value provided
either by the reporting device or pageblock_order if prdev->order is
not set.

> diff --git a/mm/page_reporting.c b/mm/page_reporting.c
> index df9c5054e1b4..293a8713ef7c 100644
> --- a/mm/page_reporting.c
> +++ b/mm/page_reporting.c
> @@ -10,6 +10,10 @@
>  #include "page_reporting.h"
>  #include "internal.h"
>
> +unsigned int page_reporting_order = pageblock_order;

Rather than setting this to pageblock_order directly you can set this
to MAX_ORDER which should be constant. Then we can just add some
checks in page_reporting_register to update it when pageblock_order is
less than page_reporting_order.

Then in the next patch you could tweak it so that it will use
"prdev->order ? : pageblock_order" instead of just pageblock_order.
Michael S. Tsirkin June 24, 2021, 7:02 p.m. UTC | #2
On Thu, Jun 24, 2021 at 06:55:13AM -0700, Alexander Duyck wrote:
> On Tue, Jun 22, 2021 at 5:34 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). 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>
> > ---
> >  Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
> >  mm/page_reporting.c                             | 8 ++++++--
> >  mm/page_reporting.h                             | 5 ++---
> >  3 files changed, 14 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).
> > +
> 
> Based on the issue found by Stephen I think we may need to tweak this
> a bit. I think we may want to just default this value to MAX_ORDER. We
> can override this value at registration time with the value provided
> either by the reporting device or pageblock_order if prdev->order is
> not set.
> 
> > diff --git a/mm/page_reporting.c b/mm/page_reporting.c
> > index df9c5054e1b4..293a8713ef7c 100644
> > --- a/mm/page_reporting.c
> > +++ b/mm/page_reporting.c
> > @@ -10,6 +10,10 @@
> >  #include "page_reporting.h"
> >  #include "internal.h"
> >
> > +unsigned int page_reporting_order = pageblock_order;
> 
> Rather than setting this to pageblock_order directly you can set this
> to MAX_ORDER which should be constant. Then we can just add some
> checks in page_reporting_register to update it when pageblock_order is
> less than page_reporting_order.
> 
> Then in the next patch you could tweak it so that it will use
> "prdev->order ? : pageblock_order" instead of just pageblock_order.

I like that! Much cleaner ... the patch is in -mm now, I think it's a
good idea to drop it and update to use this idea.
Gavin Shan June 25, 2021, 1:54 a.m. UTC | #3
On 6/25/21 5:02 AM, Michael S. Tsirkin wrote:
> On Thu, Jun 24, 2021 at 06:55:13AM -0700, Alexander Duyck wrote:
>> On Tue, Jun 22, 2021 at 5:34 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). 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>
>>> ---
>>>   Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
>>>   mm/page_reporting.c                             | 8 ++++++--
>>>   mm/page_reporting.h                             | 5 ++---
>>>   3 files changed, 14 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).
>>> +
>>
>> Based on the issue found by Stephen I think we may need to tweak this
>> a bit. I think we may want to just default this value to MAX_ORDER. We
>> can override this value at registration time with the value provided
>> either by the reporting device or pageblock_order if prdev->order is
>> not set.
>>
>>> diff --git a/mm/page_reporting.c b/mm/page_reporting.c
>>> index df9c5054e1b4..293a8713ef7c 100644
>>> --- a/mm/page_reporting.c
>>> +++ b/mm/page_reporting.c
>>> @@ -10,6 +10,10 @@
>>>   #include "page_reporting.h"
>>>   #include "internal.h"
>>>
>>> +unsigned int page_reporting_order = pageblock_order;
>>
>> Rather than setting this to pageblock_order directly you can set this
>> to MAX_ORDER which should be constant. Then we can just add some
>> checks in page_reporting_register to update it when pageblock_order is
>> less than page_reporting_order.
>>
>> Then in the next patch you could tweak it so that it will use
>> "prdev->order ? : pageblock_order" instead of just pageblock_order.
> 
> I like that! Much cleaner ... the patch is in -mm now, I think it's a
> good idea to drop it and update to use this idea.
> 

Thanks, Alex and Michael. v4 was posted to include the changes. Besides,
"module.h" is missed in page_reporting.c as Andrew found. All the changes
are squeezed to PATCH[2] and PATCH[3].

Andrew, could you help to replace the patches with v4 in linux-mm tree?
Sorry for work to you :)

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..293a8713ef7c 100644
--- a/mm/page_reporting.c
+++ b/mm/page_reporting.c
@@ -10,6 +10,10 @@ 
 #include "page_reporting.h"
 #include "internal.h"
 
+unsigned int page_reporting_order = pageblock_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 +233,7 @@  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 +243,7 @@  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 */