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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Macros for manipulating and testing page->flags
*/
#ifndef PAGE_FLAGS_THP_H
#define PAGE_FLAGS_THP_H
#include <linux/page-flags.h>
#include <linux/atomic_api.h>
#include <linux/mmzone_types.h>
#include "page-flags-helper-macros-define.h"
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/*
* PageHuge() only returns true for hugetlbfs pages, but not for
* normal or transparent huge pages.
*
* PageTransHuge() returns true for both transparent huge and
* hugetlbfs pages, but not normal pages. PageTransHuge() can only be
* called only in the core VM paths where hugetlbfs pages can't exist.
*/
static inline int PageTransHuge(struct page *page)
{
VM_BUG_ON_PAGE(PageTail(page), page);
return PageHead(page);
}
static inline bool folio_test_transhuge(struct folio *folio)
{
return folio_test_head(folio);
}
/*
* PageTransCompound returns true for both transparent huge pages
* and hugetlbfs pages, so it should only be called when it's known
* that hugetlbfs pages aren't involved.
*/
static inline int PageTransCompound(struct page *page)
{
return PageCompound(page);
}
/*
* PageTransTail returns true for both transparent huge pages
* and hugetlbfs pages, so it should only be called when it's known
* that hugetlbfs pages aren't involved.
*/
static inline int PageTransTail(struct page *page)
{
return PageTail(page);
}
/*
* PageDoubleMap indicates that the compound page is mapped with PTEs as well
* as PMDs.
*
* This is required for optimization of rmap operations for THP: we can postpone
* per small page mapcount accounting (and its overhead from atomic operations)
* until the first PMD split.
*
* For the page PageDoubleMap means ->_mapcount in all sub-pages is offset up
* by one. This reference will go away with last compound_mapcount.
*
* See also __split_huge_pmd_locked() and page_remove_anon_compound_rmap().
*/
PAGEFLAG(DoubleMap, double_map, PF_SECOND)
TESTSCFLAG(DoubleMap, double_map, PF_SECOND)
#else
TESTPAGEFLAG_FALSE(TransHuge, transhuge)
TESTPAGEFLAG_FALSE(TransCompound, transcompound)
TESTPAGEFLAG_FALSE(TransCompoundMap, transcompoundmap)
TESTPAGEFLAG_FALSE(TransTail, transtail)
PAGEFLAG_FALSE(DoubleMap, double_map)
TESTSCFLAG_FALSE(DoubleMap, double_map)
#endif
#include "page-flags-helper-macros-undefine.h"
#endif /* PAGE_FLAGS_THP_H */
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