[PATCH 3/9] huge_page: allow arch override for clear/copy_huge_page()

Ankur Arora
2023-04-03T05:23:44Z

clear/copy_huge_page() are constrained to operate on a page-at-a-time
because they also handle the CONFIG_HIGHMEM case.

Mark both __weak to allow for arch specific optimizations.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
---
mm/memory.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 6da97e6c7d21..9a6bce384616 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5645,8 +5645,12 @@ static void clear_gigantic_page(struct page *page,
}
}

-void clear_huge_page(struct page *page,
- unsigned long addr_hint, unsigned int pages_per_huge_page)
+/*
+ * clear_huge_page(): does page-at-a-time clearing to handle the
+ * CONFIG_HIGHMEM case.
+ */
+__weak void clear_huge_page(struct page *page,
+ unsigned long addr_hint, unsigned int pages_per_huge_page)
{
unsigned long addr = addr_hint &
~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1);
@@ -5712,9 +5716,13 @@ static void copy_user_gigantic_page(struct page *dst, struct page *src,
}
}

-void copy_user_huge_page(struct page *dst, struct page *src,
- unsigned long addr_hint, struct vm_area_struct *vma,
- unsigned int pages_per_huge_page)
+/*
+ * copy_user_huge_page(): does page-at-a-time copying to handle
+ * the CONFIG_HIGHMEM case.
+ */
+__weak void copy_user_huge_page(struct page *dst, struct page *src,
+ unsigned long addr_hint, struct vm_area_struct *vma,
+ unsigned int pages_per_huge_page)
{
unsigned long addr = addr_hint &
~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1);
--
2.31.1