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mm: hugetlbfs: fix cannot migrate the fallocated HugeTLB page

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commit 585fc0d2871c9318c949fbf45b1f081edd489e96 upstream.

If a new hugetlb page is allocated during fallocate it will not be
marked as active (set_page_huge_active) which will result in a later
isolate_huge_page failure when the page migration code would like to
move that page.  Such a failure would be unexpected and wrong.

Only export set_page_huge_active, just leave clear_page_huge_active as
static.  Because there are no external users.

Link: https://lkml.kernel.org/r/20210115124942.46403-3-songmuchun@bytedance.com
Fixes: 70c3547e36f5 (hugetlbfs: add hugetlbfs_fallocate())
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Muchun Song 2021-02-04 18:32:03 -08:00 committed by Greg Kroah-Hartman
parent 137482a0e5
commit 2dd160c988
3 changed files with 6 additions and 2 deletions
fs/hugetlbfs
inode.c
include/linux
hugetlb.h
mm
hugetlb.c

3
fs/hugetlbfs/inode.c

@ -665,8 +665,9 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
set_page_huge_active(page);
/*
* page_put due to reference from alloc_huge_page()
* put_page() due to reference from alloc_huge_page()
* unlock_page because locked by add_to_page_cache()
*/
put_page(page);

3
include/linux/hugetlb.h

@ -502,6 +502,9 @@ static inline void hugetlb_count_sub(long l, struct mm_struct *mm)
{
atomic_long_sub(l, &mm->hugetlb_usage);
}
void set_page_huge_active(struct page *page);
#else /* CONFIG_HUGETLB_PAGE */
struct hstate {};
#define alloc_huge_page(v, a, r) NULL

2
mm/hugetlb.c

@ -1215,7 +1215,7 @@ bool page_huge_active(struct page *page)
}
/* never called for tail page */
static void set_page_huge_active(struct page *page)
void set_page_huge_active(struct page *page)
{
VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
SetPagePrivate(&page[1]);