The patch titled
Subject: mm: hugetlb_vmemmap: simplify reset_struct_pages()
has been added to the -mm mm-unstable branch. Its filename is
mm-hugetlb_vmemmap-simplify-reset_struct_pages.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hugetlb_vmemmap-simplify-reset_struct_pages.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Subject: mm: hugetlb_vmemmap: simplify reset_struct_pages()
Date: Fri, 19 Aug 2022 11:55:32 +0800
We can choose to copy three contiguous tail pages' content to the first
three pages instead of copying one by one to simplify the code and reduce
code size from 229 bytes to 63 bytes. The BUILD_BUG_ON() aims to avoid
out-of-bounds accesses.
Link: https://lkml.kernel.org/r/20220819035532.6189-1-songmuchun@xxxxxxxxxxxxx
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb_vmemmap.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
--- a/mm/hugetlb_vmemmap.c~mm-hugetlb_vmemmap-simplify-reset_struct_pages
+++ a/mm/hugetlb_vmemmap.c
@@ -265,11 +265,10 @@ static void vmemmap_remap_pte(pte_t *pte
static inline void reset_struct_pages(struct page *start)
{
- int i;
struct page *from = start + NR_RESET_STRUCT_PAGE;
- for (i = 0; i < NR_RESET_STRUCT_PAGE; i++)
- memcpy(start + i, from, sizeof(*from));
+ BUILD_BUG_ON(NR_RESET_STRUCT_PAGE * 2 > PAGE_SIZE / sizeof(struct page));
+ memcpy(start, from, sizeof(*from) * NR_RESET_STRUCT_PAGE);
}
static void vmemmap_restore_pte(pte_t *pte, unsigned long addr,
_
Patches currently in -mm which might be from songmuchun@xxxxxxxxxxxxx are
mm-hugetlb_vmemmap-simplify-reset_struct_pages.patch
