Commit 9c5ccf2d authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

mm: remove HUGETLB_PAGE_DTOR 

We can use a bit in page[1].flags to indicate that this folio belongs to
hugetlb instead of using a value in page[1].dtors.  That lets
folio_test_hugetlb() become an inline function like it should be.  We can
also get rid of NULL_COMPOUND_DTOR.

Link: https://lkml.kernel.org/r/20230816151201.3655946-8-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 0f2f43fa

Documentation/admin-guide/kdump/vmcoreinfo.rst

+2 −8
Original line number Diff line number Diff line
@@ -325,8 +325,8 @@ NR_FREE_PAGES 
On linux-2.6.21 or later, the number of free pages is in

vm_stat[NR_FREE_PAGES]. Used to get the number of free pages.



PG_lru|PG_private|PG_swapcache|PG_swapbacked|PG_slab|PG_hwpoision|PG_head_mask

------------------------------------------------------------------------------

PG_lru|PG_private|PG_swapcache|PG_swapbacked|PG_slab|PG_hwpoision|PG_head_mask|PG_hugetlb

-----------------------------------------------------------------------------------------



Page attributes. These flags are used to filter various unnecessary for

dumping pages.
@@ -338,12 +338,6 @@ More page attributes. These flags are used to filter various unnecessary for 
dumping pages.





HUGETLB_PAGE_DTOR

-----------------



The HUGETLB_PAGE_DTOR flag denotes hugetlbfs pages. Makedumpfile

excludes these pages.



x86_64

======

include/linux/mm.h

+0 −4
Original line number Diff line number Diff line
@@ -1240,11 +1240,7 @@ void folio_copy(struct folio *dst, struct folio *src); 
unsigned long nr_free_buffer_pages(void);



enum compound_dtor_id {

	NULL_COMPOUND_DTOR,

	COMPOUND_PAGE_DTOR,

#ifdef CONFIG_HUGETLB_PAGE

	HUGETLB_PAGE_DTOR,

#endif

	TRANSHUGE_PAGE_DTOR,

	NR_COMPOUND_DTORS,

};

include/linux/page-flags.h

+33 −10
Original line number Diff line number Diff line
@@ -171,15 +171,6 @@ enum pageflags { 
	/* Remapped by swiotlb-xen. */

	PG_xen_remapped = PG_owner_priv_1,



#ifdef CONFIG_MEMORY_FAILURE

	/*

	 * Compound pages. Stored in first tail page's flags.

	 * Indicates that at least one subpage is hwpoisoned in the

	 * THP.

	 */

	PG_has_hwpoisoned = PG_error,

#endif



	/* non-lru isolated movable page */

	PG_isolated = PG_reclaim,
@@ -190,6 +181,15 @@ enum pageflags { 
	/* For self-hosted memmap pages */

	PG_vmemmap_self_hosted = PG_owner_priv_1,

#endif



	/*

	 * Flags only valid for compound pages.  Stored in first tail page's

	 * flags word.

	 */



	/* At least one page in this folio has the hwpoison flag set */

	PG_has_hwpoisoned = PG_error,

	PG_hugetlb = PG_active,

};



#define PAGEFLAGS_MASK		((1UL << NR_PAGEFLAGS) - 1)
@@ -812,7 +812,23 @@ static inline void ClearPageCompound(struct page *page) 


#ifdef CONFIG_HUGETLB_PAGE

int PageHuge(struct page *page);

bool folio_test_hugetlb(struct folio *folio);

SETPAGEFLAG(HugeTLB, hugetlb, PF_SECOND)

CLEARPAGEFLAG(HugeTLB, hugetlb, PF_SECOND)



/**

 * folio_test_hugetlb - Determine if the folio belongs to hugetlbfs

 * @folio: The folio to test.

 *

 * Context: Any context.  Caller should have a reference on the folio to

 * prevent it from being turned into a tail page.

 * Return: True for hugetlbfs folios, false for anon folios or folios

 * belonging to other filesystems.

 */

static inline bool folio_test_hugetlb(struct folio *folio)

{

	return folio_test_large(folio) &&

		test_bit(PG_hugetlb, folio_flags(folio, 1));

}

#else

TESTPAGEFLAG_FALSE(Huge, hugetlb)

#endif
@@ -1056,6 +1072,13 @@ static __always_inline void __ClearPageAnonExclusive(struct page *page) 
#define PAGE_FLAGS_CHECK_AT_PREP	\

	((PAGEFLAGS_MASK & ~__PG_HWPOISON) | LRU_GEN_MASK | LRU_REFS_MASK)



/*

 * Flags stored in the second page of a compound page.  They may overlap

 * the CHECK_AT_FREE flags above, so need to be cleared.

 */

#define PAGE_FLAGS_SECOND						\

	(1UL << PG_has_hwpoisoned	| 1UL << PG_hugetlb)



#define PAGE_FLAGS_PRIVATE				\

	(1UL << PG_private | 1UL << PG_private_2)

/**

kernel/crash_core.c

+1 −1
Original line number Diff line number Diff line
@@ -490,7 +490,7 @@ static int __init crash_save_vmcoreinfo_init(void) 
#define PAGE_BUDDY_MAPCOUNT_VALUE	(~PG_buddy)

	VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);

#ifdef CONFIG_HUGETLB_PAGE

	VMCOREINFO_NUMBER(HUGETLB_PAGE_DTOR);

	VMCOREINFO_NUMBER(PG_hugetlb);

#define PAGE_OFFLINE_MAPCOUNT_VALUE	(~PG_offline)

	VMCOREINFO_NUMBER(PAGE_OFFLINE_MAPCOUNT_VALUE);

#endif

mm/hugetlb.c

+6 −43
Original line number Diff line number Diff line
@@ -1585,25 +1585,7 @@ static inline void __clear_hugetlb_destructor(struct hstate *h, 
{

	lockdep_assert_held(&hugetlb_lock);



	/*

	 * Very subtle

	 *

	 * For non-gigantic pages set the destructor to the normal compound

	 * page dtor.  This is needed in case someone takes an additional

	 * temporary ref to the page, and freeing is delayed until they drop

	 * their reference.

	 *

	 * For gigantic pages set the destructor to the null dtor.  This

	 * destructor will never be called.  Before freeing the gigantic

	 * page destroy_compound_gigantic_folio will turn the folio into a

	 * simple group of pages.  After this the destructor does not

	 * apply.

	 *

	 */

	if (hstate_is_gigantic(h))

		folio_set_compound_dtor(folio, NULL_COMPOUND_DTOR);

	else

		folio_set_compound_dtor(folio, COMPOUND_PAGE_DTOR);

	folio_clear_hugetlb(folio);

}



/*
@@ -1690,7 +1672,7 @@ static void add_hugetlb_folio(struct hstate *h, struct folio *folio, 
		h->surplus_huge_pages_node[nid]++;

	}



	folio_set_compound_dtor(folio, HUGETLB_PAGE_DTOR);

	folio_set_hugetlb(folio);

	folio_change_private(folio, NULL);

	/*

	 * We have to set hugetlb_vmemmap_optimized again as above
@@ -1814,9 +1796,8 @@ static void free_hpage_workfn(struct work_struct *work) 
		/*

		 * The VM_BUG_ON_FOLIO(!folio_test_hugetlb(folio), folio) in

		 * folio_hstate() is going to trigger because a previous call to

		 * remove_hugetlb_folio() will call folio_set_compound_dtor

		 * (folio, NULL_COMPOUND_DTOR), so do not use folio_hstate()

		 * directly.

		 * remove_hugetlb_folio() will clear the hugetlb bit, so do

		 * not use folio_hstate() directly.

		 */

		h = size_to_hstate(page_size(page));
@@ -1955,7 +1936,7 @@ static void __prep_new_hugetlb_folio(struct hstate *h, struct folio *folio) 
{

	hugetlb_vmemmap_optimize(h, &folio->page);

	INIT_LIST_HEAD(&folio->lru);

	folio_set_compound_dtor(folio, HUGETLB_PAGE_DTOR);

	folio_set_hugetlb(folio);

	hugetlb_set_folio_subpool(folio, NULL);

	set_hugetlb_cgroup(folio, NULL);

	set_hugetlb_cgroup_rsvd(folio, NULL);
@@ -2070,28 +2051,10 @@ int PageHuge(struct page *page) 
	if (!PageCompound(page))

		return 0;

	folio = page_folio(page);

	return folio->_folio_dtor == HUGETLB_PAGE_DTOR;

	return folio_test_hugetlb(folio);

}

EXPORT_SYMBOL_GPL(PageHuge);



/**

 * folio_test_hugetlb - Determine if the folio belongs to hugetlbfs

 * @folio: The folio to test.

 *

 * Context: Any context.  Caller should have a reference on the folio to

 * prevent it from being turned into a tail page.

 * Return: True for hugetlbfs folios, false for anon folios or folios

 * belonging to other filesystems.

 */

bool folio_test_hugetlb(struct folio *folio)

{

	if (!folio_test_large(folio))

		return false;



	return folio->_folio_dtor == HUGETLB_PAGE_DTOR;

}

EXPORT_SYMBOL_GPL(folio_test_hugetlb);



/*

 * Find and lock address space (mapping) in write mode.

 *