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mm/huge_memory: remove stale page_trans_huge_mapcount()

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All users are gone, let's remove it.

Link: https://lkml.kernel.org/r/20220131162940.210846-9-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Hildenbrand 2022-03-24 18:13:53 -07:00 committed by Linus Torvalds
parent 03104c2c5d
commit 55c62fa7c5
2 changed files with 0 additions and 53 deletions
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5
include/linux/mm.h
View File

@ -834,16 +834,11 @@ static inline int total_mapcount(struct page *page)
return folio_mapcount(page_folio(page));
}
int page_trans_huge_mapcount(struct page *page);
#else
static inline int total_mapcount(struct page *page)
{
return page_mapcount(page);
}
static inline int page_trans_huge_mapcount(struct page *page)
{
return page_mapcount(page);
}
#endif
static inline struct page *virt_to_head_page(const void *x)

48
mm/huge_memory.c
View File

@ -2483,54 +2483,6 @@ static void __split_huge_page(struct page *page, struct list_head *list,
}
}
/*
* This calculates accurately how many mappings a transparent hugepage
* has (unlike page_mapcount() which isn't fully accurate). This full
* accuracy is primarily needed to know if copy-on-write faults can
* reuse the page and change the mapping to read-write instead of
* copying them. At the same time this returns the total_mapcount too.
*
* The function returns the highest mapcount any one of the subpages
* has. If the return value is one, even if different processes are
* mapping different subpages of the transparent hugepage, they can
* all reuse it, because each process is reusing a different subpage.
*
* The total_mapcount is instead counting all virtual mappings of the
* subpages. If the total_mapcount is equal to "one", it tells the
* caller all mappings belong to the same "mm" and in turn the
* anon_vma of the transparent hugepage can become the vma->anon_vma
* local one as no other process may be mapping any of the subpages.
*
* It would be more accurate to replace page_mapcount() with
* page_trans_huge_mapcount(), however we only use
* page_trans_huge_mapcount() in the copy-on-write faults where we
* need full accuracy to avoid breaking page pinning, because
* page_trans_huge_mapcount() is slower than page_mapcount().
*/
int page_trans_huge_mapcount(struct page *page)
{
int i, ret;
/* hugetlbfs shouldn't call it */
VM_BUG_ON_PAGE(PageHuge(page), page);
if (likely(!PageTransCompound(page)))
return atomic_read(&page->_mapcount) + 1;
page = compound_head(page);
ret = 0;
for (i = 0; i < thp_nr_pages(page); i++) {
int mapcount = atomic_read(&page[i]._mapcount) + 1;
ret = max(ret, mapcount);
}
if (PageDoubleMap(page))
ret -= 1;
return ret + compound_mapcount(page);
}
/* Racy check whether the huge page can be split */
bool can_split_folio(struct folio *folio, int *pextra_pins)
{