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Subject[patch 2/4] mm: page_alloc: generalize order handling in __free_pages_bootmem()
Date
__free_pages_bootmem() used to special-case higher-order frees to save
individual page checking with free_pages_bulk().

Nowadays, both zero order and non-zero order frees use free_pages(),
which checks each individual page anyway, and so there is little point
in making the distinction anymore. The higher-order loop will work
just fine for zero order pages.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
---
mm/page_alloc.c | 34 ++++++++++++----------------------
1 files changed, 12 insertions(+), 22 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 4d5e91c..1efacb3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -692,33 +692,23 @@ static void __free_pages_ok(struct page *page, unsigned int order)
local_irq_restore(flags);
}

-/*
- * permit the bootmem allocator to evade page validation on high-order frees
- */
void __meminit __free_pages_bootmem(struct page *page, unsigned int order)
{
- if (order == 0) {
- __ClearPageReserved(page);
- set_page_count(page, 0);
- set_page_refcounted(page);
- __free_page(page);
- } else {
- unsigned int nr_pages = 1 << order;
- unsigned int loop;
-
- prefetchw(page);
- for (loop = 0; loop < nr_pages; loop++) {
- struct page *p = &page[loop];
+ unsigned int nr_pages = 1 << order;
+ unsigned int loop;

- if (loop + 1 < nr_pages)
- prefetchw(p + 1);
- __ClearPageReserved(p);
- set_page_count(p, 0);
- }
+ prefetchw(page);
+ for (loop = 0; loop < nr_pages; loop++) {
+ struct page *p = &page[loop];

- set_page_refcounted(page);
- __free_pages(page, order);
+ if (loop + 1 < nr_pages)
+ prefetchw(p + 1);
+ __ClearPageReserved(p);
+ set_page_count(p, 0);
}
+
+ set_page_refcounted(page);
+ __free_pages(page, order);
}


--
1.7.7.3


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