[PATCH v2 02/14] mm/page_alloc: split prep_compound_page into head and tail subparts
From: Joao Martins <hidden>
Date: 2021-06-17 18:47:03
Also in:
linux-doc, nvdimm
Subsystem:
memory management, memory management - page allocator, the rest · Maintainers:
Andrew Morton, Vlastimil Babka, Linus Torvalds
Split the utility function prep_compound_page() into head and tail counterparts, and use them accordingly. This is in preparation for sharing the storage for / deduplicating compound page metadata. Signed-off-by: Joao Martins <redacted> --- mm/page_alloc.c | 32 +++++++++++++++++++++----------- 1 file changed, 21 insertions(+), 11 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8836e54721ae..95967ce55829 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c@@ -741,24 +741,34 @@ void free_compound_page(struct page *page) free_the_page(page, compound_order(page)); } +static void prep_compound_head(struct page *page, unsigned int order) +{ + set_compound_page_dtor(page, COMPOUND_PAGE_DTOR); + set_compound_order(page, order); + atomic_set(compound_mapcount_ptr(page), -1); + if (hpage_pincount_available(page)) + atomic_set(compound_pincount_ptr(page), 0); +} + +static void prep_compound_tail(struct page *head, int tail_idx) +{ + struct page *p = head + tail_idx; + + set_page_count(p, 0); + p->mapping = TAIL_MAPPING; + set_compound_head(p, head); +} + void prep_compound_page(struct page *page, unsigned int order) { int i; int nr_pages = 1 << order; __SetPageHead(page); - for (i = 1; i < nr_pages; i++) { - struct page *p = page + i; - set_page_count(p, 0); - p->mapping = TAIL_MAPPING; - set_compound_head(p, page); - } + for (i = 1; i < nr_pages; i++) + prep_compound_tail(page, i); - set_compound_page_dtor(page, COMPOUND_PAGE_DTOR); - set_compound_order(page, order); - atomic_set(compound_mapcount_ptr(page), -1); - if (hpage_pincount_available(page)) - atomic_set(compound_pincount_ptr(page), 0); + prep_compound_head(page, order); } #ifdef CONFIG_DEBUG_PAGEALLOC
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2.17.1