Commit 18f39629 authored by Qi Zheng's avatar Qi Zheng Committed by Andrew Morton
Browse files

mm: hugetlb: kill set_huge_swap_pte_at() 

Commit e5251fd4 ("mm/hugetlb: introduce set_huge_swap_pte_at()
helper") add set_huge_swap_pte_at() to handle swap entries on
architectures that support hugepages consisting of contiguous ptes.  And
currently the set_huge_swap_pte_at() is only overridden by arm64.

set_huge_swap_pte_at() provide a sz parameter to help determine the number
of entries to be updated.  But in fact, all hugetlb swap entries contain
pfn information, so we can find the corresponding folio through the pfn
recorded in the swap entry, then the folio_size() is the number of entries
that need to be updated.

And considering that users will easily cause bugs by ignoring the
difference between set_huge_swap_pte_at() and set_huge_pte_at().  Let's
handle swap entries in set_huge_pte_at() and remove the
set_huge_swap_pte_at(), then we can call set_huge_pte_at() anywhere, which
simplifies our coding.

Link: https://lkml.kernel.org/r/20220626145717.53572-1-zhengqi.arch@bytedance.com


Signed-off-by: default avatarQi Zheng <zhengqi.arch@bytedance.com>
Acked-by: default avatarMuchun Song <songmuchun@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent ade63b41

arch/arm64/include/asm/hugetlb.h

+0 −3
Original line number Diff line number Diff line
@@ -46,9 +46,6 @@ extern void huge_pte_clear(struct mm_struct *mm, unsigned long addr, 
			   pte_t *ptep, unsigned long sz);

#define __HAVE_ARCH_HUGE_PTEP_GET

extern pte_t huge_ptep_get(pte_t *ptep);

extern void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr,

				 pte_t *ptep, pte_t pte, unsigned long sz);

#define set_huge_swap_pte_at set_huge_swap_pte_at



void __init arm64_hugetlb_cma_reserve(void);

arch/arm64/mm/hugetlbpage.c

+17 −17
Original line number Diff line number Diff line
@@ -238,6 +238,13 @@ static void clear_flush(struct mm_struct *mm, 
	flush_tlb_range(&vma, saddr, addr);

}



static inline struct folio *hugetlb_swap_entry_to_folio(swp_entry_t entry)

{

	VM_BUG_ON(!is_migration_entry(entry) && !is_hwpoison_entry(entry));



	return page_folio(pfn_to_page(swp_offset(entry)));

}



void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,

			    pte_t *ptep, pte_t pte)

{
@@ -247,11 +254,16 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, 
	unsigned long pfn, dpfn;

	pgprot_t hugeprot;



	/*

	 * Code needs to be expanded to handle huge swap and migration

	 * entries. Needed for HUGETLB and MEMORY_FAILURE.

	 */

	WARN_ON(!pte_present(pte));

	if (!pte_present(pte)) {

		struct folio *folio;



		folio = hugetlb_swap_entry_to_folio(pte_to_swp_entry(pte));

		ncontig = num_contig_ptes(folio_size(folio), &pgsize);



		for (i = 0; i < ncontig; i++, ptep++)

			set_pte_at(mm, addr, ptep, pte);

		return;

	}



	if (!pte_cont(pte)) {

		set_pte_at(mm, addr, ptep, pte);
@@ -269,18 +281,6 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, 
		set_pte_at(mm, addr, ptep, pfn_pte(pfn, hugeprot));

}



void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr,

			  pte_t *ptep, pte_t pte, unsigned long sz)

{

	int i, ncontig;

	size_t pgsize;



	ncontig = num_contig_ptes(sz, &pgsize);



	for (i = 0; i < ncontig; i++, ptep++)

		set_pte(ptep, pte);

}



pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,

		      unsigned long addr, unsigned long sz)

{

include/linux/hugetlb.h

+0 −13
Original line number Diff line number Diff line
@@ -903,14 +903,6 @@ static inline void hugetlb_count_sub(long l, struct mm_struct *mm) 
	atomic_long_sub(l, &mm->hugetlb_usage);

}



#ifndef set_huge_swap_pte_at

static inline void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr,

					pte_t *ptep, pte_t pte, unsigned long sz)

{

	set_huge_pte_at(mm, addr, ptep, pte);

}

#endif



#ifndef huge_ptep_modify_prot_start

#define huge_ptep_modify_prot_start huge_ptep_modify_prot_start

static inline pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma,
@@ -1094,11 +1086,6 @@ static inline void hugetlb_count_sub(long l, struct mm_struct *mm) 
{

}



static inline void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr,

					pte_t *ptep, pte_t pte, unsigned long sz)

{

}



static inline pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,

					  unsigned long addr, pte_t *ptep)

{

mm/hugetlb.c

+3 −5
Original line number Diff line number Diff line
@@ -4798,12 +4798,11 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, 
				entry = swp_entry_to_pte(swp_entry);

				if (userfaultfd_wp(src_vma) && uffd_wp)

					entry = huge_pte_mkuffd_wp(entry);

				set_huge_swap_pte_at(src, addr, src_pte,

						     entry, sz);

				set_huge_pte_at(src, addr, src_pte, entry);

			}

			if (!userfaultfd_wp(dst_vma) && uffd_wp)

				entry = huge_pte_clear_uffd_wp(entry);

			set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);

			set_huge_pte_at(dst, addr, dst_pte, entry);

		} else if (unlikely(is_pte_marker(entry))) {

			/*

			 * We copy the pte marker only if the dst vma has
@@ -6344,8 +6343,7 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma, 
					newpte = pte_swp_mkuffd_wp(newpte);

				else if (uffd_wp_resolve)

					newpte = pte_swp_clear_uffd_wp(newpte);

				set_huge_swap_pte_at(mm, address, ptep,

						     newpte, psize);

				set_huge_pte_at(mm, address, ptep, newpte);

				pages++;

			}

			spin_unlock(ptl);

mm/rmap.c

+3 −8
Original line number Diff line number Diff line
@@ -1618,9 +1618,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, 
			pteval = swp_entry_to_pte(make_hwpoison_entry(subpage));

			if (folio_test_hugetlb(folio)) {

				hugetlb_count_sub(folio_nr_pages(folio), mm);

				set_huge_swap_pte_at(mm, address,

						     pvmw.pte, pteval,

						     vma_mmu_pagesize(vma));

				set_huge_pte_at(mm, address, pvmw.pte, pteval);

			} else {

				dec_mm_counter(mm, mm_counter(&folio->page));

				set_pte_at(mm, address, pvmw.pte, pteval);
@@ -2004,9 +2002,7 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, 
			pteval = swp_entry_to_pte(make_hwpoison_entry(subpage));

			if (folio_test_hugetlb(folio)) {

				hugetlb_count_sub(folio_nr_pages(folio), mm);

				set_huge_swap_pte_at(mm, address,

						     pvmw.pte, pteval,

						     vma_mmu_pagesize(vma));

				set_huge_pte_at(mm, address, pvmw.pte, pteval);

			} else {

				dec_mm_counter(mm, mm_counter(&folio->page));

				set_pte_at(mm, address, pvmw.pte, pteval);
@@ -2074,8 +2070,7 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, 
			if (pte_uffd_wp(pteval))

				swp_pte = pte_swp_mkuffd_wp(swp_pte);

			if (folio_test_hugetlb(folio))

				set_huge_swap_pte_at(mm, address, pvmw.pte,

						     swp_pte, vma_mmu_pagesize(vma));

				set_huge_pte_at(mm, address, pvmw.pte, swp_pte);

			else

				set_pte_at(mm, address, pvmw.pte, swp_pte);

			trace_set_migration_pte(address, pte_val(swp_pte),