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Re: [PATCH v4 17/34] s390: Convert various pgalloc functions to use ptdescs



On Mon, Jun 12, 2023 at 02:04:06PM -0700, Vishal Moola (Oracle) wrote:
> As part of the conversions to replace pgtable constructor/destructors with
> ptdesc equivalents, convert various page table functions to use ptdescs.
> 
> Some of the functions use the *get*page*() helper functions. Convert
> these to use pagetable_alloc() and ptdesc_address() instead to help
> standardize page tables further.
> 
> Signed-off-by: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx>

Acked-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>

> ---
>  arch/s390/include/asm/pgalloc.h |   4 +-
>  arch/s390/include/asm/tlb.h     |   4 +-
>  arch/s390/mm/pgalloc.c          | 108 ++++++++++++++++----------------
>  3 files changed, 59 insertions(+), 57 deletions(-)
> 
> diff --git a/arch/s390/include/asm/pgalloc.h b/arch/s390/include/asm/pgalloc.h
> index 17eb618f1348..00ad9b88fda9 100644
> --- a/arch/s390/include/asm/pgalloc.h
> +++ b/arch/s390/include/asm/pgalloc.h
> @@ -86,7 +86,7 @@ static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, 
> unsigned long vmaddr)
>       if (!table)
>               return NULL;
>       crst_table_init(table, _SEGMENT_ENTRY_EMPTY);
> -     if (!pgtable_pmd_page_ctor(virt_to_page(table))) {
> +     if (!pagetable_pmd_ctor(virt_to_ptdesc(table))) {
>               crst_table_free(mm, table);
>               return NULL;
>       }
> @@ -97,7 +97,7 @@ static inline void pmd_free(struct mm_struct *mm, pmd_t 
> *pmd)
>  {
>       if (mm_pmd_folded(mm))
>               return;
> -     pgtable_pmd_page_dtor(virt_to_page(pmd));
> +     pagetable_pmd_dtor(virt_to_ptdesc(pmd));
>       crst_table_free(mm, (unsigned long *) pmd);
>  }
>  
> diff --git a/arch/s390/include/asm/tlb.h b/arch/s390/include/asm/tlb.h
> index b91f4a9b044c..383b1f91442c 100644
> --- a/arch/s390/include/asm/tlb.h
> +++ b/arch/s390/include/asm/tlb.h
> @@ -89,12 +89,12 @@ static inline void pmd_free_tlb(struct mmu_gather *tlb, 
> pmd_t *pmd,
>  {
>       if (mm_pmd_folded(tlb->mm))
>               return;
> -     pgtable_pmd_page_dtor(virt_to_page(pmd));
> +     pagetable_pmd_dtor(virt_to_ptdesc(pmd));
>       __tlb_adjust_range(tlb, address, PAGE_SIZE);
>       tlb->mm->context.flush_mm = 1;
>       tlb->freed_tables = 1;
>       tlb->cleared_puds = 1;
> -     tlb_remove_table(tlb, pmd);
> +     tlb_remove_ptdesc(tlb, pmd);
>  }
>  
>  /*
> diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c
> index 6b99932abc66..eeb7c95b98cf 100644
> --- a/arch/s390/mm/pgalloc.c
> +++ b/arch/s390/mm/pgalloc.c
> @@ -43,17 +43,17 @@ __initcall(page_table_register_sysctl);
>  
>  unsigned long *crst_table_alloc(struct mm_struct *mm)
>  {
> -     struct page *page = alloc_pages(GFP_KERNEL, CRST_ALLOC_ORDER);
> +     struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL, CRST_ALLOC_ORDER);
>  
> -     if (!page)
> +     if (!ptdesc)
>               return NULL;
> -     arch_set_page_dat(page, CRST_ALLOC_ORDER);
> -     return (unsigned long *) page_to_virt(page);
> +     arch_set_page_dat(ptdesc_page(ptdesc), CRST_ALLOC_ORDER);
> +     return (unsigned long *) ptdesc_to_virt(ptdesc);
>  }
>  
>  void crst_table_free(struct mm_struct *mm, unsigned long *table)
>  {
> -     free_pages((unsigned long)table, CRST_ALLOC_ORDER);
> +     pagetable_free(virt_to_ptdesc(table));
>  }
>  
>  static void __crst_table_upgrade(void *arg)
> @@ -140,21 +140,21 @@ static inline unsigned int atomic_xor_bits(atomic_t *v, 
> unsigned int bits)
>  
>  struct page *page_table_alloc_pgste(struct mm_struct *mm)
>  {
> -     struct page *page;
> +     struct ptdesc *ptdesc;
>       u64 *table;
>  
> -     page = alloc_page(GFP_KERNEL);
> -     if (page) {
> -             table = (u64 *)page_to_virt(page);
> +     ptdesc = pagetable_alloc(GFP_KERNEL, 0);
> +     if (ptdesc) {
> +             table = (u64 *)ptdesc_to_virt(ptdesc);
>               memset64(table, _PAGE_INVALID, PTRS_PER_PTE);
>               memset64(table + PTRS_PER_PTE, 0, PTRS_PER_PTE);
>       }
> -     return page;
> +     return ptdesc_page(ptdesc);
>  }
>  
>  void page_table_free_pgste(struct page *page)
>  {
> -     __free_page(page);
> +     pagetable_free(page_ptdesc(page));
>  }
>  
>  #endif /* CONFIG_PGSTE */
> @@ -230,7 +230,7 @@ void page_table_free_pgste(struct page *page)
>  unsigned long *page_table_alloc(struct mm_struct *mm)
>  {
>       unsigned long *table;
> -     struct page *page;
> +     struct ptdesc *ptdesc;
>       unsigned int mask, bit;
>  
>       /* Try to get a fragment of a 4K page as a 2K page table */
> @@ -238,9 +238,9 @@ unsigned long *page_table_alloc(struct mm_struct *mm)
>               table = NULL;
>               spin_lock_bh(&mm->context.lock);
>               if (!list_empty(&mm->context.pgtable_list)) {
> -                     page = list_first_entry(&mm->context.pgtable_list,
> -                                             struct page, lru);
> -                     mask = atomic_read(&page->pt_frag_refcount);
> +                     ptdesc = list_first_entry(&mm->context.pgtable_list,
> +                                             struct ptdesc, pt_list);
> +                     mask = atomic_read(&ptdesc->pt_frag_refcount);
>                       /*
>                        * The pending removal bits must also be checked.
>                        * Failure to do so might lead to an impossible
> @@ -253,13 +253,13 @@ unsigned long *page_table_alloc(struct mm_struct *mm)
>                        */
>                       mask = (mask | (mask >> 4)) & 0x03U;
>                       if (mask != 0x03U) {
> -                             table = (unsigned long *) page_to_virt(page);
> +                             table = (unsigned long *) 
> ptdesc_to_virt(ptdesc);
>                               bit = mask & 1;         /* =1 -> second 2K */
>                               if (bit)
>                                       table += PTRS_PER_PTE;
> -                             atomic_xor_bits(&page->pt_frag_refcount,
> +                             atomic_xor_bits(&ptdesc->pt_frag_refcount,
>                                                       0x01U << bit);
> -                             list_del(&page->lru);
> +                             list_del(&ptdesc->pt_list);
>                       }
>               }
>               spin_unlock_bh(&mm->context.lock);
> @@ -267,27 +267,27 @@ unsigned long *page_table_alloc(struct mm_struct *mm)
>                       return table;
>       }
>       /* Allocate a fresh page */
> -     page = alloc_page(GFP_KERNEL);
> -     if (!page)
> +     ptdesc = pagetable_alloc(GFP_KERNEL, 0);
> +     if (!ptdesc)
>               return NULL;
> -     if (!pgtable_pte_page_ctor(page)) {
> -             __free_page(page);
> +     if (!pagetable_pte_ctor(ptdesc)) {
> +             pagetable_free(ptdesc);
>               return NULL;
>       }
> -     arch_set_page_dat(page, 0);
> +     arch_set_page_dat(ptdesc_page(ptdesc), 0);
>       /* Initialize page table */
> -     table = (unsigned long *) page_to_virt(page);
> +     table = (unsigned long *) ptdesc_to_virt(ptdesc);
>       if (mm_alloc_pgste(mm)) {
>               /* Return 4K page table with PGSTEs */
> -             atomic_xor_bits(&page->pt_frag_refcount, 0x03U);
> +             atomic_xor_bits(&ptdesc->pt_frag_refcount, 0x03U);
>               memset64((u64 *)table, _PAGE_INVALID, PTRS_PER_PTE);
>               memset64((u64 *)table + PTRS_PER_PTE, 0, PTRS_PER_PTE);
>       } else {
>               /* Return the first 2K fragment of the page */
> -             atomic_xor_bits(&page->pt_frag_refcount, 0x01U);
> +             atomic_xor_bits(&ptdesc->pt_frag_refcount, 0x01U);
>               memset64((u64 *)table, _PAGE_INVALID, 2 * PTRS_PER_PTE);
>               spin_lock_bh(&mm->context.lock);
> -             list_add(&page->lru, &mm->context.pgtable_list);
> +             list_add(&ptdesc->pt_list, &mm->context.pgtable_list);
>               spin_unlock_bh(&mm->context.lock);
>       }
>       return table;
> @@ -309,9 +309,8 @@ static void page_table_release_check(struct page *page, 
> void *table,
>  void page_table_free(struct mm_struct *mm, unsigned long *table)
>  {
>       unsigned int mask, bit, half;
> -     struct page *page;
> +     struct ptdesc *ptdesc = virt_to_ptdesc(table);
>  
> -     page = virt_to_page(table);
>       if (!mm_alloc_pgste(mm)) {
>               /* Free 2K page table fragment of a 4K page */
>               bit = ((unsigned long) table & 
> ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t));
> @@ -321,39 +320,38 @@ void page_table_free(struct mm_struct *mm, unsigned 
> long *table)
>                * will happen outside of the critical section from this
>                * function or from __tlb_remove_table()
>                */
> -             mask = atomic_xor_bits(&page->pt_frag_refcount, 0x11U << bit);
> +             mask = atomic_xor_bits(&ptdesc->pt_frag_refcount, 0x11U << bit);
>               if (mask & 0x03U)
> -                     list_add(&page->lru, &mm->context.pgtable_list);
> +                     list_add(&ptdesc->pt_list, &mm->context.pgtable_list);
>               else
> -                     list_del(&page->lru);
> +                     list_del(&ptdesc->pt_list);
>               spin_unlock_bh(&mm->context.lock);
> -             mask = atomic_xor_bits(&page->pt_frag_refcount, 0x10U << bit);
> +             mask = atomic_xor_bits(&ptdesc->pt_frag_refcount, 0x10U << bit);
>               if (mask != 0x00U)
>                       return;
>               half = 0x01U << bit;
>       } else {
>               half = 0x03U;
> -             mask = atomic_xor_bits(&page->pt_frag_refcount, 0x03U);
> +             mask = atomic_xor_bits(&ptdesc->pt_frag_refcount, 0x03U);
>       }
>  
> -     page_table_release_check(page, table, half, mask);
> -     pgtable_pte_page_dtor(page);
> -     __free_page(page);
> +     page_table_release_check(ptdesc_page(ptdesc), table, half, mask);
> +     pagetable_pte_dtor(ptdesc);
> +     pagetable_free(ptdesc);
>  }
>  
>  void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table,
>                        unsigned long vmaddr)
>  {
>       struct mm_struct *mm;
> -     struct page *page;
>       unsigned int bit, mask;
> +     struct ptdesc *ptdesc = virt_to_ptdesc(table);
>  
>       mm = tlb->mm;
> -     page = virt_to_page(table);
>       if (mm_alloc_pgste(mm)) {
>               gmap_unlink(mm, table, vmaddr);
>               table = (unsigned long *) ((unsigned long)table | 0x03U);
> -             tlb_remove_table(tlb, table);
> +             tlb_remove_ptdesc(tlb, table);
>               return;
>       }
>       bit = ((unsigned long) table & ~PAGE_MASK) / 
> (PTRS_PER_PTE*sizeof(pte_t));
> @@ -363,11 +361,11 @@ void page_table_free_rcu(struct mmu_gather *tlb, 
> unsigned long *table,
>        * outside of the critical section from __tlb_remove_table() or from
>        * page_table_free()
>        */
> -     mask = atomic_xor_bits(&page->pt_frag_refcount, 0x11U << bit);
> +     mask = atomic_xor_bits(&ptdesc->pt_frag_refcount, 0x11U << bit);
>       if (mask & 0x03U)
> -             list_add_tail(&page->lru, &mm->context.pgtable_list);
> +             list_add_tail(&ptdesc->pt_list, &mm->context.pgtable_list);
>       else
> -             list_del(&page->lru);
> +             list_del(&ptdesc->pt_list);
>       spin_unlock_bh(&mm->context.lock);
>       table = (unsigned long *) ((unsigned long) table | (0x01U << bit));
>       tlb_remove_table(tlb, table);
> @@ -377,7 +375,7 @@ void __tlb_remove_table(void *_table)
>  {
>       unsigned int mask = (unsigned long) _table & 0x03U, half = mask;
>       void *table = (void *)((unsigned long) _table ^ mask);
> -     struct page *page = virt_to_page(table);
> +     struct ptdesc *ptdesc = virt_to_ptdesc(table);
>  
>       switch (half) {
>       case 0x00U:     /* pmd, pud, or p4d */
> @@ -385,18 +383,18 @@ void __tlb_remove_table(void *_table)
>               return;
>       case 0x01U:     /* lower 2K of a 4K page table */
>       case 0x02U:     /* higher 2K of a 4K page table */
> -             mask = atomic_xor_bits(&page->pt_frag_refcount, mask << 4);
> +             mask = atomic_xor_bits(&ptdesc->pt_frag_refcount, mask << 4);
>               if (mask != 0x00U)
>                       return;
>               break;
>       case 0x03U:     /* 4K page table with pgstes */
> -             mask = atomic_xor_bits(&page->pt_frag_refcount, 0x03U);
> +             mask = atomic_xor_bits(&ptdesc->pt_frag_refcount, 0x03U);
>               break;
>       }
>  
> -     page_table_release_check(page, table, half, mask);
> -     pgtable_pte_page_dtor(page);
> -     __free_page(page);
> +     page_table_release_check(ptdesc_page(ptdesc), table, half, mask);
> +     pagetable_pte_dtor(ptdesc);
> +     pagetable_free(ptdesc);
>  }
>  
>  /*
> @@ -424,16 +422,20 @@ static void base_pgt_free(unsigned long *table)
>  static unsigned long *base_crst_alloc(unsigned long val)
>  {
>       unsigned long *table;
> +     struct ptdesc *ptdesc;
>  
> -     table = (unsigned long *)__get_free_pages(GFP_KERNEL, CRST_ALLOC_ORDER);
> -     if (table)
> -             crst_table_init(table, val);
> +     ptdesc = pagetable_alloc(GFP_KERNEL, CRST_ALLOC_ORDER);
> +     if (!ptdesc)
> +             return NULL;
> +     table = ptdesc_address(ptdesc);
> +
> +     crst_table_init(table, val);
>       return table;
>  }
>  
>  static void base_crst_free(unsigned long *table)
>  {
> -     free_pages((unsigned long)table, CRST_ALLOC_ORDER);
> +     pagetable_free(virt_to_ptdesc(table));
>  }
>  
>  #define BASE_ADDR_END_FUNC(NAME, SIZE)                                       
> \
> -- 
> 2.40.1
> 
> 

-- 
Sincerely yours,
Mike.



 


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