diff mbox series

[RFC,20/37] mm: compaction: Reserve metadata storage in compaction_alloc()

Message ID 20230823131350.114942-21-alexandru.elisei@arm.com (mailing list archive)
State Handled Elsewhere
Headers show
Series [RFC,01/37] mm: page_alloc: Rename gfp_to_alloc_flags_cma -> gfp_to_alloc_flags_fast | expand

Commit Message

Alexandru Elisei Aug. 23, 2023, 1:13 p.m. UTC
If the source page being migrated has metadata associated with it, make
sure to reserve the metadata storage when choosing a suitable destination
page from the free list.

Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
---
 mm/compaction.c | 9 +++++++++
 mm/internal.h   | 1 +
 2 files changed, 10 insertions(+)

Comments

Peter Collingbourne Nov. 21, 2023, 4:49 a.m. UTC | #1
Hi Alexandru,

On Wed, Aug 23, 2023 at 6:16 AM Alexandru Elisei
<alexandru.elisei@arm.com> wrote:
>
> If the source page being migrated has metadata associated with it, make
> sure to reserve the metadata storage when choosing a suitable destination
> page from the free list.
>
> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
> ---
>  mm/compaction.c | 9 +++++++++
>  mm/internal.h   | 1 +
>  2 files changed, 10 insertions(+)
>
> diff --git a/mm/compaction.c b/mm/compaction.c
> index cc0139fa0cb0..af2ee3085623 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -570,6 +570,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
>         bool locked = false;
>         unsigned long blockpfn = *start_pfn;
>         unsigned int order;
> +       int ret;
>
>         /* Strict mode is for isolation, speed is secondary */
>         if (strict)
> @@ -626,6 +627,11 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
>
>                 /* Found a free page, will break it into order-0 pages */
>                 order = buddy_order(page);
> +               if (metadata_storage_enabled() && cc->reserve_metadata) {
> +                       ret = reserve_metadata_storage(page, order, cc->gfp_mask);

At this point the zone lock is held and preemption is disabled, which
makes it invalid to call reserve_metadata_storage.

Peter

> +                       if (ret)
> +                               goto isolate_fail;
> +               }
>                 isolated = __isolate_free_page(page, order);
>                 if (!isolated)
>                         break;
> @@ -1757,6 +1763,9 @@ static struct folio *compaction_alloc(struct folio *src, unsigned long data)
>         struct compact_control *cc = (struct compact_control *)data;
>         struct folio *dst;
>
> +       if (metadata_storage_enabled())
> +               cc->reserve_metadata = folio_has_metadata(src);
> +
>         if (list_empty(&cc->freepages)) {
>                 isolate_freepages(cc);
>
> diff --git a/mm/internal.h b/mm/internal.h
> index d28ac0085f61..046cc264bfbe 100644
> --- a/mm/internal.h
> +++ b/mm/internal.h
> @@ -492,6 +492,7 @@ struct compact_control {
>                                          */
>         bool alloc_contig;              /* alloc_contig_range allocation */
>         bool source_has_metadata;       /* source pages have associated metadata */
> +       bool reserve_metadata;
>  };
>
>  /*
> --
> 2.41.0
>
Alexandru Elisei Nov. 21, 2023, 11:54 a.m. UTC | #2
Hi Peter,

On Mon, Nov 20, 2023 at 08:49:32PM -0800, Peter Collingbourne wrote:
> Hi Alexandru,
> 
> On Wed, Aug 23, 2023 at 6:16 AM Alexandru Elisei
> <alexandru.elisei@arm.com> wrote:
> >
> > If the source page being migrated has metadata associated with it, make
> > sure to reserve the metadata storage when choosing a suitable destination
> > page from the free list.
> >
> > Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
> > ---
> >  mm/compaction.c | 9 +++++++++
> >  mm/internal.h   | 1 +
> >  2 files changed, 10 insertions(+)
> >
> > diff --git a/mm/compaction.c b/mm/compaction.c
> > index cc0139fa0cb0..af2ee3085623 100644
> > --- a/mm/compaction.c
> > +++ b/mm/compaction.c
> > @@ -570,6 +570,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
> >         bool locked = false;
> >         unsigned long blockpfn = *start_pfn;
> >         unsigned int order;
> > +       int ret;
> >
> >         /* Strict mode is for isolation, speed is secondary */
> >         if (strict)
> > @@ -626,6 +627,11 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
> >
> >                 /* Found a free page, will break it into order-0 pages */
> >                 order = buddy_order(page);
> > +               if (metadata_storage_enabled() && cc->reserve_metadata) {
> > +                       ret = reserve_metadata_storage(page, order, cc->gfp_mask);
> 
> At this point the zone lock is held and preemption is disabled, which
> makes it invalid to call reserve_metadata_storage.

You are correct, I missed that. I dropped reserving tag storage during
compaction in the next iteration, so fortunately I unintentionally fixed
it.

Thanks,
Alex

> 
> Peter
> 
> > +                       if (ret)
> > +                               goto isolate_fail;
> > +               }
> >                 isolated = __isolate_free_page(page, order);
> >                 if (!isolated)
> >                         break;
> > @@ -1757,6 +1763,9 @@ static struct folio *compaction_alloc(struct folio *src, unsigned long data)
> >         struct compact_control *cc = (struct compact_control *)data;
> >         struct folio *dst;
> >
> > +       if (metadata_storage_enabled())
> > +               cc->reserve_metadata = folio_has_metadata(src);
> > +
> >         if (list_empty(&cc->freepages)) {
> >                 isolate_freepages(cc);
> >
> > diff --git a/mm/internal.h b/mm/internal.h
> > index d28ac0085f61..046cc264bfbe 100644
> > --- a/mm/internal.h
> > +++ b/mm/internal.h
> > @@ -492,6 +492,7 @@ struct compact_control {
> >                                          */
> >         bool alloc_contig;              /* alloc_contig_range allocation */
> >         bool source_has_metadata;       /* source pages have associated metadata */
> > +       bool reserve_metadata;
> >  };
> >
> >  /*
> > --
> > 2.41.0
> >
diff mbox series

Patch

diff --git a/mm/compaction.c b/mm/compaction.c
index cc0139fa0cb0..af2ee3085623 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -570,6 +570,7 @@  static unsigned long isolate_freepages_block(struct compact_control *cc,
 	bool locked = false;
 	unsigned long blockpfn = *start_pfn;
 	unsigned int order;
+	int ret;
 
 	/* Strict mode is for isolation, speed is secondary */
 	if (strict)
@@ -626,6 +627,11 @@  static unsigned long isolate_freepages_block(struct compact_control *cc,
 
 		/* Found a free page, will break it into order-0 pages */
 		order = buddy_order(page);
+		if (metadata_storage_enabled() && cc->reserve_metadata) {
+			ret = reserve_metadata_storage(page, order, cc->gfp_mask);
+			if (ret)
+				goto isolate_fail;
+		}
 		isolated = __isolate_free_page(page, order);
 		if (!isolated)
 			break;
@@ -1757,6 +1763,9 @@  static struct folio *compaction_alloc(struct folio *src, unsigned long data)
 	struct compact_control *cc = (struct compact_control *)data;
 	struct folio *dst;
 
+	if (metadata_storage_enabled())
+		cc->reserve_metadata = folio_has_metadata(src);
+
 	if (list_empty(&cc->freepages)) {
 		isolate_freepages(cc);
 
diff --git a/mm/internal.h b/mm/internal.h
index d28ac0085f61..046cc264bfbe 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -492,6 +492,7 @@  struct compact_control {
 					 */
 	bool alloc_contig;		/* alloc_contig_range allocation */
 	bool source_has_metadata;	/* source pages have associated metadata */
+	bool reserve_metadata;
 };
 
 /*