Messages in this thread | | | From | "Aneesh Kumar K.V" <> | Subject | Re: [PATCHv4 19/24] thp, mm: use migration entries to freeze page counts on split | Date | Mon, 30 Mar 2015 19:49:43 +0530 |
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"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> writes:
> Currently, we rely on compound_lock() to get page counts stable on > splitting page refcounting. To get it work we also take the lock on > get_page() and put_page() which is hot path. > > This patch rework splitting code to setup migration entries to stabilaze > page count/mapcount before distribute refcounts. It means we don't need > to compound lock in get_page()/put_page(). > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> > --- > include/linux/migrate.h | 3 + > include/linux/mm.h | 1 + > include/linux/pagemap.h | 9 ++- > mm/huge_memory.c | 188 +++++++++++++++++++++++++++++++++++------------- > mm/internal.h | 26 +++++-- > mm/migrate.c | 79 +++++++++++--------- > mm/rmap.c | 21 ------ > 7 files changed, 218 insertions(+), 109 deletions(-) > > diff --git a/include/linux/migrate.h b/include/linux/migrate.h > index 78baed5f2952..b9bc86c24829 100644 > --- a/include/linux/migrate.h > +++ b/include/linux/migrate.h > @@ -43,6 +43,9 @@ extern int migrate_page_move_mapping(struct address_space *mapping, > struct page *newpage, struct page *page, > struct buffer_head *head, enum migrate_mode mode, > int extra_count); > +extern int __remove_migration_pte(struct page *new, struct vm_area_struct *vma, > + unsigned long addr, pte_t *ptep, struct page *old); > + > #else > > static inline void putback_movable_pages(struct list_head *l) {} > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 28aeae6e553b..43a9993f1333 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -981,6 +981,7 @@ extern struct address_space *page_mapping(struct page *page); > /* Neutral page->mapping pointer to address_space or anon_vma or other */ > static inline void *page_rmapping(struct page *page) > { > + page = compound_head(page); > return (void *)((unsigned long)page->mapping & ~PAGE_MAPPING_FLAGS); > } >
The above hunk is related to this patch ?. Are we calling page_rmapping on tail pages now ? If so it needs additonal comment why we handle them differently now. Or split it to a seperate patch ?
-aneesh
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