[PATCH v5 21/39] mm: Make prep_transhuge_page return its argument
From: Matthew Wilcox <willy@infradead.org>
Date: 2020-05-29 03:03:05
Also in:
linux-fsdevel, lkml
Subsystem:
memory management, memory management - thp (transparent huge page), the rest · Maintainers:
Andrew Morton, David Hildenbrand, Lorenzo Stoakes, Linus Torvalds
From: "Matthew Wilcox (Oracle)" <willy@infradead.org> By permitting NULL or order-0 pages as an argument, and returning the argument, callers can write: return prep_transhuge_page(alloc_pages(...)); instead of assigning the result to a temporary variable and conditionally passing that to prep_transhuge_page(). Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Kirill A. Shutemov <redacted> --- include/linux/huge_mm.h | 7 +++++-- mm/huge_memory.c | 9 +++++++-- 2 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 1f6245091917..6a8502278f41 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h@@ -193,7 +193,7 @@ extern unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags); -extern void prep_transhuge_page(struct page *page); +extern struct page *prep_transhuge_page(struct page *page); extern void free_transhuge_page(struct page *page); bool is_transparent_hugepage(struct page *page);
@@ -358,7 +358,10 @@ static inline bool transhuge_vma_suitable(struct vm_area_struct *vma, return false; } -static inline void prep_transhuge_page(struct page *page) {} +static inline struct page *prep_transhuge_page(struct page *page) +{ + return page; +} static inline bool is_transparent_hugepage(struct page *page) {
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 6ecd1045113b..7a5e2b470bc7 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c@@ -508,15 +508,20 @@ static inline struct deferred_split *get_deferred_split_queue(struct page *page) } #endif -void prep_transhuge_page(struct page *page) +struct page *prep_transhuge_page(struct page *page) { + if (!page || compound_order(page) == 0) + return page; /* - * we use page->mapping and page->indexlru in second tail page + * we use page->mapping and page->index in second tail page * as list_head: assuming THP order >= 2 */ + BUG_ON(compound_order(page) == 1); INIT_LIST_HEAD(page_deferred_list(page)); set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); + + return page; } bool is_transparent_hugepage(struct page *page)
--
2.26.2