Commit 4059971c authored by Qi Zheng's avatar Qi Zheng Committed by Andrew Morton
Browse files

mm: do_zap_pte_range: return any_skipped information to the caller 

Let the caller of do_zap_pte_range() know whether we skip zap ptes or
reinstall uffd-wp ptes through any_skipped parameter, so that subsequent
commits can use this information in zap_pte_range() to detect whether the
PTE page can be reclaimed.

Link: https://lkml.kernel.org/r/59f33ec9f74e9f058ed319b0bfadd76b0f7adf9b.1733305182.git.zhengqi.arch@bytedance.com


Signed-off-by: default avatarQi Zheng <zhengqi.arch@bytedance.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: Zach O'Keefe <zokeefe@google.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 735fad44

mm/memory.c

+21 −15
Original line number Diff line number Diff line
@@ -1501,7 +1501,7 @@ static __always_inline void zap_present_folio_ptes(struct mmu_gather *tlb, 
		struct vm_area_struct *vma, struct folio *folio,

		struct page *page, pte_t *pte, pte_t ptent, unsigned int nr,

		unsigned long addr, struct zap_details *details, int *rss,

		bool *force_flush, bool *force_break)

		bool *force_flush, bool *force_break, bool *any_skipped)

{

	struct mm_struct *mm = tlb->mm;

	bool delay_rmap = false;
@@ -1527,8 +1527,8 @@ static __always_inline void zap_present_folio_ptes(struct mmu_gather *tlb, 
	arch_check_zapped_pte(vma, ptent);

	tlb_remove_tlb_entries(tlb, pte, nr, addr);

	if (unlikely(userfaultfd_pte_wp(vma, ptent)))

		zap_install_uffd_wp_if_needed(vma, addr, pte, nr, details,

					      ptent);

		*any_skipped = zap_install_uffd_wp_if_needed(vma, addr, pte,

							     nr, details, ptent);



	if (!delay_rmap) {

		folio_remove_rmap_ptes(folio, page, nr, vma);
@@ -1552,7 +1552,7 @@ static inline int zap_present_ptes(struct mmu_gather *tlb, 
		struct vm_area_struct *vma, pte_t *pte, pte_t ptent,

		unsigned int max_nr, unsigned long addr,

		struct zap_details *details, int *rss, bool *force_flush,

		bool *force_break)

		bool *force_break, bool *any_skipped)

{

	const fpb_t fpb_flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY;

	struct mm_struct *mm = tlb->mm;
@@ -1567,15 +1567,17 @@ static inline int zap_present_ptes(struct mmu_gather *tlb, 
		arch_check_zapped_pte(vma, ptent);

		tlb_remove_tlb_entry(tlb, pte, addr);

		if (userfaultfd_pte_wp(vma, ptent))

			zap_install_uffd_wp_if_needed(vma, addr, pte, 1,

						      details, ptent);

			*any_skipped = zap_install_uffd_wp_if_needed(vma, addr,

						pte, 1, details, ptent);

		ksm_might_unmap_zero_page(mm, ptent);

		return 1;

	}



	folio = page_folio(page);

	if (unlikely(!should_zap_folio(details, folio)))

	if (unlikely(!should_zap_folio(details, folio))) {

		*any_skipped = true;

		return 1;

	}



	/*

	 * Make sure that the common "small folio" case is as fast as possible
@@ -1587,22 +1589,23 @@ static inline int zap_present_ptes(struct mmu_gather *tlb, 


		zap_present_folio_ptes(tlb, vma, folio, page, pte, ptent, nr,

				       addr, details, rss, force_flush,

				       force_break);

				       force_break, any_skipped);

		return nr;

	}

	zap_present_folio_ptes(tlb, vma, folio, page, pte, ptent, 1, addr,

			       details, rss, force_flush, force_break);

			       details, rss, force_flush, force_break, any_skipped);

	return 1;

}



static inline int zap_nonpresent_ptes(struct mmu_gather *tlb,

		struct vm_area_struct *vma, pte_t *pte, pte_t ptent,

		unsigned int max_nr, unsigned long addr,

		struct zap_details *details, int *rss)

		struct zap_details *details, int *rss, bool *any_skipped)

{

	swp_entry_t entry;

	int nr = 1;



	*any_skipped = true;

	entry = pte_to_swp_entry(ptent);

	if (is_device_private_entry(entry) ||

		is_device_exclusive_entry(entry)) {
@@ -1660,7 +1663,7 @@ static inline int zap_nonpresent_ptes(struct mmu_gather *tlb, 
		WARN_ON_ONCE(1);

	}

	clear_not_present_full_ptes(vma->vm_mm, addr, pte, nr, tlb->fullmm);

	zap_install_uffd_wp_if_needed(vma, addr, pte, nr, details, ptent);

	*any_skipped = zap_install_uffd_wp_if_needed(vma, addr, pte, nr, details, ptent);



	return nr;

}
@@ -1669,7 +1672,8 @@ static inline int do_zap_pte_range(struct mmu_gather *tlb, 
				   struct vm_area_struct *vma, pte_t *pte,

				   unsigned long addr, unsigned long end,

				   struct zap_details *details, int *rss,

				   bool *force_flush, bool *force_break)

				   bool *force_flush, bool *force_break,

				   bool *any_skipped)

{

	pte_t ptent = ptep_get(pte);

	int max_nr = (end - addr) / PAGE_SIZE;
@@ -1691,10 +1695,11 @@ static inline int do_zap_pte_range(struct mmu_gather *tlb, 


	if (pte_present(ptent))

		nr += zap_present_ptes(tlb, vma, pte, ptent, max_nr, addr,

				       details, rss, force_flush, force_break);

				       details, rss, force_flush, force_break,

				       any_skipped);

	else

		nr += zap_nonpresent_ptes(tlb, vma, pte, ptent, max_nr, addr,

					  details, rss);

					  details, rss, any_skipped);



	return nr;

}
@@ -1705,6 +1710,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, 
				struct zap_details *details)

{

	bool force_flush = false, force_break = false;

	bool any_skipped = false;

	struct mm_struct *mm = tlb->mm;

	int rss[NR_MM_COUNTERS];

	spinlock_t *ptl;
@@ -1725,7 +1731,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, 
			break;



		nr = do_zap_pte_range(tlb, vma, pte, addr, end, details, rss,

				      &force_flush, &force_break);

				      &force_flush, &force_break, &any_skipped);

		if (unlikely(force_break)) {

			addr += nr * PAGE_SIZE;

			break;