The patch titled
Subject: mm: use aligned address in clear_gigantic_page()
has been added to the -mm mm-unstable branch. Its filename is
mm-use-aligned-address-in-clear_gigantic_page.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-use-aligned-address-in-clear_gigantic_page.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: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Subject: mm: use aligned address in clear_gigantic_page()
Date: Sat, 26 Oct 2024 13:43:06 +0800
When clearing gigantic page, it zeros page from the first page to the last
page, if directly passing addr_hint which maybe not the address of the
first page of folio, then some archs could flush the wrong cache if it
does use the addr_hint as a hint. For non-gigantic page, it calculates
the base address inside, even passed the wrong addr_hint, it only has
performance impact as the process_huge_page() wants to process target page
last to keep its cache lines hot), no functional impact.
Let's pass the real accessed address to folio_zero_user() and use the
aligned address in clear_gigantic_page() to fix it.
Link: https://lkml.kernel.org/r/20241026054307.3896926-1-wangkefeng.wang@xxxxxxxxxx
Fixes: 78fefd04c123 ("mm: memory: convert clear_huge_page() to folio_zero_user()")
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Huang Ying <ying.huang@xxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/hugetlbfs/inode.c | 2 +-
mm/memory.c | 1 +
2 files changed, 2 insertions(+), 1 deletion(-)
--- a/fs/hugetlbfs/inode.c~mm-use-aligned-address-in-clear_gigantic_page
+++ a/fs/hugetlbfs/inode.c
@@ -819,7 +819,7 @@ static long hugetlbfs_fallocate(struct f
error = PTR_ERR(folio);
goto out;
}
- folio_zero_user(folio, ALIGN_DOWN(addr, hpage_size));
+ folio_zero_user(folio, addr);
__folio_mark_uptodate(folio);
error = hugetlb_add_to_page_cache(folio, mapping, index);
if (unlikely(error)) {
--- a/mm/memory.c~mm-use-aligned-address-in-clear_gigantic_page
+++ a/mm/memory.c
@@ -6810,6 +6810,7 @@ static void clear_gigantic_page(struct f
int i;
might_sleep();
+ addr = ALIGN_DOWN(addr, folio_size(folio));
for (i = 0; i < nr_pages; i++) {
cond_resched();
clear_user_highpage(folio_page(folio, i), addr + i * PAGE_SIZE);
_
Patches currently in -mm which might be from wangkefeng.wang@xxxxxxxxxx are
mm-remove-unused-hugepage-for-vma_alloc_folio.patch
tmpfs-dont-enable-large-folios-if-not-supported.patch
mm-huge_memory-move-file_thp_enabled-into-huge_memoryc.patch
mm-shmem-remove-__shmem_huge_global_enabled.patch
mm-use-aligned-address-in-clear_gigantic_page.patch
mm-use-aligned-address-in-copy_user_gigantic_page.patch
