diff mbox series

[v4,11/11] mm/memory_hotplug: remove a wrapper for alloc_migration_target()

Message ID 1594107889-32228-12-git-send-email-iamjoonsoo.kim@lge.com (mailing list archive)
State New, archived
Headers show
Series clean-up the migration target allocation functions | expand

Commit Message

Joonsoo Kim July 7, 2020, 7:44 a.m. UTC 
From: Joonsoo Kim <iamjoonsoo.kim@lge.com>

To calculate the correct node to migrate the page for hotplug, we need
to check node id of the page. Wrapper for alloc_migration_target() exists
for this purpose.

However, Vlastimil informs that all migration source pages come from
a single node. In this case, we don't need to check the node id for each
page and we don't need to re-set the target nodemask for each page by
using the wrapper. Set up the migration_target_control once and use it for
all pages.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
---
 mm/memory_hotplug.c | 46 ++++++++++++++++++++++------------------------
 1 file changed, 22 insertions(+), 24 deletions(-)

Comments

Michal Hocko July 7, 2020, 11:52 a.m. UTC | #1 
On Tue 07-07-20 16:44:49, Joonsoo Kim wrote:
> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> 
> To calculate the correct node to migrate the page for hotplug, we need
> to check node id of the page. Wrapper for alloc_migration_target() exists
> for this purpose.
> 
> However, Vlastimil informs that all migration source pages come from
> a single node. In this case, we don't need to check the node id for each
> page and we don't need to re-set the target nodemask for each page by
> using the wrapper. Set up the migration_target_control once and use it for
> all pages.

yes, memory offlining only operates on a single zone. Have a look at
test_pages_in_a_zone().

> 
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
>  mm/memory_hotplug.c | 46 ++++++++++++++++++++++------------------------
>  1 file changed, 22 insertions(+), 24 deletions(-)
> 
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 86bc2ad..269e8ca 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1265,27 +1265,6 @@ static int scan_movable_pages(unsigned long start, unsigned long end,
>  	return 0;
>  }
>  
> -static struct page *new_node_page(struct page *page, unsigned long private)
> -{
> -	nodemask_t nmask = node_states[N_MEMORY];
> -	struct migration_target_control mtc = {
> -		.nid = page_to_nid(page),
> -		.nmask = &nmask,
> -		.gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
> -	};
> -
> -	/*
> -	 * try to allocate from a different node but reuse this node if there
> -	 * are no other online nodes to be used (e.g. we are offlining a part
> -	 * of the only existing node)
> -	 */
> -	node_clear(mtc.nid, *mtc.nmask);
> -	if (nodes_empty(*mtc.nmask))
> -		node_set(mtc.nid, *mtc.nmask);
> -
> -	return alloc_migration_target(page, (unsigned long)&mtc);
> -}
> -
>  static int
>  do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
>  {
> @@ -1345,9 +1324,28 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
>  		put_page(page);
>  	}
>  	if (!list_empty(&source)) {
> -		/* Allocate a new page from the nearest neighbor node */
> -		ret = migrate_pages(&source, new_node_page, NULL, 0,
> -					MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
> +		nodemask_t nmask = node_states[N_MEMORY];
> +		struct migration_target_control mtc = {
> +			.nmask = &nmask,
> +			.gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
> +		};
> +
> +		/*
> +		 * We have checked that migration range is on a single zone so
> +		 * we can use the nid of the first page to all the others.
> +		 */
> +		mtc.nid = page_to_nid(list_first_entry(&source, struct page, lru));
> +
> +		/*
> +		 * try to allocate from a different node but reuse this node
> +		 * if there are no other online nodes to be used (e.g. we are
> +		 * offlining a part of the only existing node)
> +		 */
> +		node_clear(mtc.nid, *mtc.nmask);
> +		if (nodes_empty(*mtc.nmask))
> +			node_set(mtc.nid, *mtc.nmask);
> +		ret = migrate_pages(&source, alloc_migration_target, NULL,
> +			(unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
>  		if (ret) {
>  			list_for_each_entry(page, &source, lru) {
>  				pr_warn("migrating pfn %lx failed ret:%d ",
> -- 
> 2.7.4
>
Vlastimil Babka July 7, 2020, 3:09 p.m. UTC | #2 
On 7/7/20 9:44 AM, js1304@gmail.com wrote:
> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> 
> To calculate the correct node to migrate the page for hotplug, we need
> to check node id of the page. Wrapper for alloc_migration_target() exists
> for this purpose.
> 
> However, Vlastimil informs that all migration source pages come from
> a single node. In this case, we don't need to check the node id for each
> page and we don't need to re-set the target nodemask for each page by
> using the wrapper. Set up the migration_target_control once and use it for
> all pages.
> 
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

Thanks! Nitpick below.

> @@ -1345,9 +1324,28 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
>  		put_page(page);
>  	}
>  	if (!list_empty(&source)) {
> -		/* Allocate a new page from the nearest neighbor node */
> -		ret = migrate_pages(&source, new_node_page, NULL, 0,
> -					MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
> +		nodemask_t nmask = node_states[N_MEMORY];
> +		struct migration_target_control mtc = {
> +			.nmask = &nmask,
> +			.gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
> +		};
> +
> +		/*
> +		 * We have checked that migration range is on a single zone so
> +		 * we can use the nid of the first page to all the others.
> +		 */
> +		mtc.nid = page_to_nid(list_first_entry(&source, struct page, lru));
> +
> +		/*
> +		 * try to allocate from a different node but reuse this node
> +		 * if there are no other online nodes to be used (e.g. we are
> +		 * offlining a part of the only existing node)
> +		 */
> +		node_clear(mtc.nid, *mtc.nmask);
> +		if (nodes_empty(*mtc.nmask))
> +			node_set(mtc.nid, *mtc.nmask);

You could have kept using 'nmask' instead of '*mtc.nmask'. Actually that applies
to patch 6 too, for less churn.

> +		ret = migrate_pages(&source, alloc_migration_target, NULL,
> +			(unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
>  		if (ret) {
>  			list_for_each_entry(page, &source, lru) {
>  				pr_warn("migrating pfn %lx failed ret:%d ",
>
Joonsoo Kim July 9, 2020, 3:25 a.m. UTC | #3 
2020년 7월 8일 (수) 오전 1:34, Vlastimil Babka <vbabka@suse.cz>님이 작성:
>
> On 7/7/20 9:44 AM, js1304@gmail.com wrote:
> > From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> >
> > To calculate the correct node to migrate the page for hotplug, we need
> > to check node id of the page. Wrapper for alloc_migration_target() exists
> > for this purpose.
> >
> > However, Vlastimil informs that all migration source pages come from
> > a single node. In this case, we don't need to check the node id for each
> > page and we don't need to re-set the target nodemask for each page by
> > using the wrapper. Set up the migration_target_control once and use it for
> > all pages.
> >
> > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>
> Acked-by: Vlastimil Babka <vbabka@suse.cz>
>
> Thanks! Nitpick below.
>
> > @@ -1345,9 +1324,28 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
> >               put_page(page);
> >       }
> >       if (!list_empty(&source)) {
> > -             /* Allocate a new page from the nearest neighbor node */
> > -             ret = migrate_pages(&source, new_node_page, NULL, 0,
> > -                                     MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
> > +             nodemask_t nmask = node_states[N_MEMORY];
> > +             struct migration_target_control mtc = {
> > +                     .nmask = &nmask,
> > +                     .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
> > +             };
> > +
> > +             /*
> > +              * We have checked that migration range is on a single zone so
> > +              * we can use the nid of the first page to all the others.
> > +              */
> > +             mtc.nid = page_to_nid(list_first_entry(&source, struct page, lru));
> > +
> > +             /*
> > +              * try to allocate from a different node but reuse this node
> > +              * if there are no other online nodes to be used (e.g. we are
> > +              * offlining a part of the only existing node)
> > +              */
> > +             node_clear(mtc.nid, *mtc.nmask);
> > +             if (nodes_empty(*mtc.nmask))
> > +                     node_set(mtc.nid, *mtc.nmask);
>
> You could have kept using 'nmask' instead of '*mtc.nmask'. Actually that applies
> to patch 6 too, for less churn.

You are right. I will change it.

Thanks.
diff mbox series

Patch

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 86bc2ad..269e8ca 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1265,27 +1265,6 @@  static int scan_movable_pages(unsigned long start, unsigned long end,
 	return 0;
 }
 
-static struct page *new_node_page(struct page *page, unsigned long private)
-{
-	nodemask_t nmask = node_states[N_MEMORY];
-	struct migration_target_control mtc = {
-		.nid = page_to_nid(page),
-		.nmask = &nmask,
-		.gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
-	};
-
-	/*
-	 * try to allocate from a different node but reuse this node if there
-	 * are no other online nodes to be used (e.g. we are offlining a part
-	 * of the only existing node)
-	 */
-	node_clear(mtc.nid, *mtc.nmask);
-	if (nodes_empty(*mtc.nmask))
-		node_set(mtc.nid, *mtc.nmask);
-
-	return alloc_migration_target(page, (unsigned long)&mtc);
-}
-
 static int
 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
 {
@@ -1345,9 +1324,28 @@  do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
 		put_page(page);
 	}
 	if (!list_empty(&source)) {
-		/* Allocate a new page from the nearest neighbor node */
-		ret = migrate_pages(&source, new_node_page, NULL, 0,
-					MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
+		nodemask_t nmask = node_states[N_MEMORY];
+		struct migration_target_control mtc = {
+			.nmask = &nmask,
+			.gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
+		};
+
+		/*
+		 * We have checked that migration range is on a single zone so
+		 * we can use the nid of the first page to all the others.
+		 */
+		mtc.nid = page_to_nid(list_first_entry(&source, struct page, lru));
+
+		/*
+		 * try to allocate from a different node but reuse this node
+		 * if there are no other online nodes to be used (e.g. we are
+		 * offlining a part of the only existing node)
+		 */
+		node_clear(mtc.nid, *mtc.nmask);
+		if (nodes_empty(*mtc.nmask))
+			node_set(mtc.nid, *mtc.nmask);
+		ret = migrate_pages(&source, alloc_migration_target, NULL,
+			(unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
 		if (ret) {
 			list_for_each_entry(page, &source, lru) {
 				pr_warn("migrating pfn %lx failed ret:%d ",