Re: [PATCH v2 2/6] mm/balloon_compaction: keep ballooned pages away from normal migration path
On Sat, Aug 30, 2014 at 08:41:13PM +0400, Konstantin Khlebnikov wrote: > From: Konstantin Khlebnikov > > Proper testing shows yet another problem in balloon migration: it works only > once for each page. balloon_page_movable() check page flags and page_count. > In __unmap_and_move page is locked, reference counter is elevated, so > balloon_page_movable() _always_ fails here. As result in __unmap_and_move() > migration goes to the normal migration path. > > Balloon ->migratepage() is so special, it returns MIGRATEPAGE_BALLOON_SUCCESS > instead of MIGRATEPAGE_SUCCESS. After that in move_to_new_page() successfully > migrated page got NULL into its mapping pointer and loses connectivity with > balloon and ability for further migration. > > It's safe to use __is_movable_balloon_page here: page is isolated and pinned. > > Signed-off-by: Konstantin Khlebnikov > Cc: stable # v3.8 > --- > include/linux/balloon_compaction.h |5 + > mm/migrate.c |2 +- > 2 files changed, 6 insertions(+), 1 deletion(-) > > diff --git a/include/linux/balloon_compaction.h > b/include/linux/balloon_compaction.h > index 53d482e..284fc1d 100644 > --- a/include/linux/balloon_compaction.h > +++ b/include/linux/balloon_compaction.h > @@ -258,6 +258,11 @@ static inline void balloon_page_delete(struct page *page) > list_del(>lru); > } > > +static inline bool __is_movable_balloon_page(struct page *page) > +{ > + return false; > +} > + > static inline bool balloon_page_movable(struct page *page) > { > return false; > diff --git a/mm/migrate.c b/mm/migrate.c > index 905b1aa..57c94f9 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -873,7 +873,7 @@ static int __unmap_and_move(struct page *page, struct > page *newpage, > } > } > > - if (unlikely(balloon_page_movable(page))) { > + if (unlikely(__is_movable_balloon_page(page))) { > /* >* A ballooned page does not need any special attention from >* physical to virtual reverse mapping procedures. > Acked-by: Rafael Aquini -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v2 2/6] mm/balloon_compaction: keep ballooned pages away from normal migration path
On Sat, Aug 30, 2014 at 08:41:13PM +0400, Konstantin Khlebnikov wrote: From: Konstantin Khlebnikov k.khlebni...@samsung.com Proper testing shows yet another problem in balloon migration: it works only once for each page. balloon_page_movable() check page flags and page_count. In __unmap_and_move page is locked, reference counter is elevated, so balloon_page_movable() _always_ fails here. As result in __unmap_and_move() migration goes to the normal migration path. Balloon -migratepage() is so special, it returns MIGRATEPAGE_BALLOON_SUCCESS instead of MIGRATEPAGE_SUCCESS. After that in move_to_new_page() successfully migrated page got NULL into its mapping pointer and loses connectivity with balloon and ability for further migration. It's safe to use __is_movable_balloon_page here: page is isolated and pinned. Signed-off-by: Konstantin Khlebnikov k.khlebni...@samsung.com Cc: stable sta...@vger.kernel.org # v3.8 --- include/linux/balloon_compaction.h |5 + mm/migrate.c |2 +- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h index 53d482e..284fc1d 100644 --- a/include/linux/balloon_compaction.h +++ b/include/linux/balloon_compaction.h @@ -258,6 +258,11 @@ static inline void balloon_page_delete(struct page *page) list_del(page-lru); } +static inline bool __is_movable_balloon_page(struct page *page) +{ + return false; +} + static inline bool balloon_page_movable(struct page *page) { return false; diff --git a/mm/migrate.c b/mm/migrate.c index 905b1aa..57c94f9 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -873,7 +873,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, } } - if (unlikely(balloon_page_movable(page))) { + if (unlikely(__is_movable_balloon_page(page))) { /* * A ballooned page does not need any special attention from * physical to virtual reverse mapping procedures. Acked-by: Rafael Aquini aqu...@redhat.com -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH v2 2/6] mm/balloon_compaction: keep ballooned pages away from normal migration path
From: Konstantin Khlebnikov Proper testing shows yet another problem in balloon migration: it works only once for each page. balloon_page_movable() check page flags and page_count. In __unmap_and_move page is locked, reference counter is elevated, so balloon_page_movable() _always_ fails here. As result in __unmap_and_move() migration goes to the normal migration path. Balloon ->migratepage() is so special, it returns MIGRATEPAGE_BALLOON_SUCCESS instead of MIGRATEPAGE_SUCCESS. After that in move_to_new_page() successfully migrated page got NULL into its mapping pointer and loses connectivity with balloon and ability for further migration. It's safe to use __is_movable_balloon_page here: page is isolated and pinned. Signed-off-by: Konstantin Khlebnikov Cc: stable # v3.8 --- include/linux/balloon_compaction.h |5 + mm/migrate.c |2 +- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h index 53d482e..284fc1d 100644 --- a/include/linux/balloon_compaction.h +++ b/include/linux/balloon_compaction.h @@ -258,6 +258,11 @@ static inline void balloon_page_delete(struct page *page) list_del(>lru); } +static inline bool __is_movable_balloon_page(struct page *page) +{ + return false; +} + static inline bool balloon_page_movable(struct page *page) { return false; diff --git a/mm/migrate.c b/mm/migrate.c index 905b1aa..57c94f9 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -873,7 +873,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, } } - if (unlikely(balloon_page_movable(page))) { + if (unlikely(__is_movable_balloon_page(page))) { /* * A ballooned page does not need any special attention from * physical to virtual reverse mapping procedures. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH v2 2/6] mm/balloon_compaction: keep ballooned pages away from normal migration path
From: Konstantin Khlebnikov k.khlebni...@samsung.com Proper testing shows yet another problem in balloon migration: it works only once for each page. balloon_page_movable() check page flags and page_count. In __unmap_and_move page is locked, reference counter is elevated, so balloon_page_movable() _always_ fails here. As result in __unmap_and_move() migration goes to the normal migration path. Balloon -migratepage() is so special, it returns MIGRATEPAGE_BALLOON_SUCCESS instead of MIGRATEPAGE_SUCCESS. After that in move_to_new_page() successfully migrated page got NULL into its mapping pointer and loses connectivity with balloon and ability for further migration. It's safe to use __is_movable_balloon_page here: page is isolated and pinned. Signed-off-by: Konstantin Khlebnikov k.khlebni...@samsung.com Cc: stable sta...@vger.kernel.org # v3.8 --- include/linux/balloon_compaction.h |5 + mm/migrate.c |2 +- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h index 53d482e..284fc1d 100644 --- a/include/linux/balloon_compaction.h +++ b/include/linux/balloon_compaction.h @@ -258,6 +258,11 @@ static inline void balloon_page_delete(struct page *page) list_del(page-lru); } +static inline bool __is_movable_balloon_page(struct page *page) +{ + return false; +} + static inline bool balloon_page_movable(struct page *page) { return false; diff --git a/mm/migrate.c b/mm/migrate.c index 905b1aa..57c94f9 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -873,7 +873,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, } } - if (unlikely(balloon_page_movable(page))) { + if (unlikely(__is_movable_balloon_page(page))) { /* * A ballooned page does not need any special attention from * physical to virtual reverse mapping procedures. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/