[PATCH v5 3/4] mm: support Svnapot in hugetlb page

Conor Dooley conor at kernel.org
Tue Oct 4 11:43:29 PDT 2022


On Mon, Oct 03, 2022 at 09:47:20PM +0800, panqinglin2020 at iscas.ac.cn wrote:
> From: Qinglin Pan <panqinglin2020 at iscas.ac.cn>
> 
> Svnapot can be used to support 64KB hugetlb page, so it can become a new
> option when using hugetlbfs. This commit adds a basic implementation of

s/this commit adds/add

> hugetlb page, and support 64KB as a size in it by using Svnapot.
> 

I think the test could could be kept out of the commit message & under a
--- line.

> For test, boot kernel with command line contains "default_hugepagesz=64K
> hugepagesz=64K hugepages=20" and run a simple test like this:
> 
> int main() {
> 	void *addr;
> 	addr = mmap(NULL, 64 * 1024, PROT_WRITE | PROT_READ,
> 			MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB | MAP_HUGE_64KB, -1, 0);
> 	printf("back from mmap \n");
> 	long *ptr = (long *)addr;
> 	unsigned int i = 0;
> 	for(; i < 8 * 1024;i += 512) {
> 		printf("%lp \n", ptr);
> 		*ptr = 0xdeafabcd12345678;
> 		ptr += 512;
> 	}
> 	ptr = (long *)addr;
> 	i = 0;
> 	for(; i < 8 * 1024;i += 512) {
> 		if (*ptr != 0xdeafabcd12345678) {
> 			printf("failed! 0x%lx \n", *ptr);
> 			break;
> 		}
> 		ptr += 512;
> 	}
> 	if(i == 8 * 1024)
> 		printf("simple test passed!\n");
> }
> 
> And it should be passed.
> 
> Signed-off-by: Qinglin Pan <panqinglin2020 at iscas.ac.cn>
> 
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 4354024aae21..3d5ec1391046 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -43,7 +43,7 @@ config RISCV
>  	select ARCH_USE_QUEUED_RWLOCKS
>  	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
>  	select ARCH_WANT_FRAME_POINTERS
> -	select ARCH_WANT_GENERAL_HUGETLB
> +	select ARCH_WANT_GENERAL_HUGETLB if !RISCV_ISA_SVNAPOT
>  	select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
>  	select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU
>  	select BUILDTIME_TABLE_SORT if MMU
> diff --git a/arch/riscv/include/asm/hugetlb.h b/arch/riscv/include/asm/hugetlb.h
> index a5c2ca1d1cd8..79cbb482f0a0 100644
> --- a/arch/riscv/include/asm/hugetlb.h
> +++ b/arch/riscv/include/asm/hugetlb.h
> @@ -2,7 +2,35 @@
>  #ifndef _ASM_RISCV_HUGETLB_H
>  #define _ASM_RISCV_HUGETLB_H
>  
> -#include <asm-generic/hugetlb.h>
>  #include <asm/page.h>
>  
> +#ifdef CONFIG_RISCV_ISA_SVNAPOT
> +pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags);
> +#define arch_make_huge_pte arch_make_huge_pte
> +#define __HAVE_ARCH_HUGE_SET_HUGE_PTE_AT
> +void set_huge_pte_at(struct mm_struct *mm,
> +		     unsigned long addr, pte_t *ptep, pte_t pte);
> +#define __HAVE_ARCH_HUGE_PTEP_GET_AND_CLEAR
> +pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
> +			      unsigned long addr, pte_t *ptep);
> +#define __HAVE_ARCH_HUGE_PTEP_CLEAR_FLUSH
> +pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
> +			    unsigned long addr, pte_t *ptep);
> +#define __HAVE_ARCH_HUGE_PTEP_SET_ACCESS_FLAGS
> +int huge_ptep_set_access_flags(struct vm_area_struct *vma,
> +			       unsigned long addr, pte_t *ptep,
> +			       pte_t pte, int dirty);
> +#define __HAVE_ARCH_HUGE_PTEP_SET_WRPROTECT
> +void huge_ptep_set_wrprotect(struct mm_struct *mm,
> +			     unsigned long addr, pte_t *ptep);
> +#define __HAVE_ARCH_HUGE_PTE_CLEAR
> +void huge_pte_clear(struct mm_struct *mm, unsigned long addr,
> +		    pte_t *ptep, unsigned long sz);
> +#define set_huge_swap_pte_at riscv_set_huge_swap_pte_at
> +void riscv_set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr,
> +				pte_t *ptep, pte_t pte, unsigned long sz);
> +#endif /*CONFIG_RISCV_ISA_SVNAPOT*/

Maybe I am just getting old or something, but some whitespace would go a
long way here I think.

I'm not qualified for any further comments on this patch however :/
Conor.

> +
> +#include <asm-generic/hugetlb.h>
> +
>  #endif /* _ASM_RISCV_HUGETLB_H */
> diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
> index ac70b0fd9a9a..1ea06476902a 100644
> --- a/arch/riscv/include/asm/page.h
> +++ b/arch/riscv/include/asm/page.h
> @@ -17,7 +17,7 @@
>  #define PAGE_MASK	(~(PAGE_SIZE - 1))
>  
>  #ifdef CONFIG_64BIT
> -#define HUGE_MAX_HSTATE		2
> +#define HUGE_MAX_HSTATE		3
>  #else
>  #define HUGE_MAX_HSTATE		1
>  #endif
> diff --git a/arch/riscv/mm/hugetlbpage.c b/arch/riscv/mm/hugetlbpage.c
> index 932dadfdca54..faa207826260 100644
> --- a/arch/riscv/mm/hugetlbpage.c
> +++ b/arch/riscv/mm/hugetlbpage.c
> @@ -2,6 +2,239 @@
>  #include <linux/hugetlb.h>
>  #include <linux/err.h>
>  
> +#ifdef CONFIG_RISCV_ISA_SVNAPOT
> +pte_t *huge_pte_alloc(struct mm_struct *mm,
> +		      struct vm_area_struct *vma,
> +		      unsigned long addr,
> +		      unsigned long sz)
> +{
> +	pgd_t *pgdp = pgd_offset(mm, addr);
> +	p4d_t *p4dp = p4d_alloc(mm, pgdp, addr);
> +	pud_t *pudp = pud_alloc(mm, p4dp, addr);
> +	pmd_t *pmdp = pmd_alloc(mm, pudp, addr);
> +
> +	if (sz == NAPOT_CONT64KB_SIZE) {
> +		if (!pmdp)
> +			return NULL;
> +		WARN_ON(addr & (sz - 1));
> +		return pte_alloc_map(mm, pmdp, addr);
> +	}
> +
> +	return NULL;
> +}
> +
> +pte_t *huge_pte_offset(struct mm_struct *mm,
> +		       unsigned long addr,
> +		       unsigned long sz)
> +{
> +	pgd_t *pgdp;
> +	p4d_t *p4dp;
> +	pud_t *pudp;
> +	pmd_t *pmdp;
> +	pte_t *ptep = NULL;
> +
> +	pgdp = pgd_offset(mm, addr);
> +	if (!pgd_present(READ_ONCE(*pgdp)))
> +		return NULL;
> +
> +	p4dp = p4d_offset(pgdp, addr);
> +	if (!p4d_present(READ_ONCE(*p4dp)))
> +		return NULL;
> +
> +	pudp = pud_offset(p4dp, addr);
> +	if (!pud_present(READ_ONCE(*pudp)))
> +		return NULL;
> +
> +	pmdp = pmd_offset(pudp, addr);
> +	if (!pmd_present(READ_ONCE(*pmdp)))
> +		return NULL;
> +
> +	if (sz == NAPOT_CONT64KB_SIZE)
> +		ptep = pte_offset_kernel(pmdp, (addr & ~NAPOT_CONT64KB_MASK));
> +
> +	return ptep;
> +}
> +
> +static int napot_pte_num(pte_t pte)
> +{
> +	if (pte_val(pte) & _PAGE_NAPOT)
> +		return NAPOT_64KB_PTE_NUM;
> +
> +	pr_warn("%s: unrecognized napot pte size 0x%lx\n",
> +		__func__, pte_val(pte));
> +	return 1;
> +}
> +
> +static pte_t get_clear_flush(struct mm_struct *mm,
> +			     unsigned long addr,
> +			     pte_t *ptep,
> +			     unsigned long pte_num)
> +{
> +	pte_t orig_pte = huge_ptep_get(ptep);
> +	bool valid = pte_val(orig_pte);
> +	unsigned long i, saddr = addr;
> +
> +	for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++) {
> +		pte_t pte = ptep_get_and_clear(mm, addr, ptep);
> +
> +		if (pte_dirty(pte))
> +			orig_pte = pte_mkdirty(orig_pte);
> +
> +		if (pte_young(pte))
> +			orig_pte = pte_mkyoung(orig_pte);
> +	}
> +
> +	if (valid) {
> +		struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
> +
> +		flush_tlb_range(&vma, saddr, addr);
> +	}
> +	return orig_pte;
> +}
> +
> +static void clear_flush(struct mm_struct *mm,
> +			unsigned long addr,
> +			pte_t *ptep,
> +			unsigned long pte_num)
> +{
> +	struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
> +	unsigned long i, saddr = addr;
> +
> +	for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++)
> +		pte_clear(mm, addr, ptep);
> +
> +	flush_tlb_range(&vma, saddr, addr);
> +}
> +
> +pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
> +{
> +	if (shift == NAPOT_CONT64KB_SHIFT)
> +		entry = pte_mknapot(entry, NAPOT_CONT64KB_SHIFT - PAGE_SHIFT);
> +
> +	return entry;
> +}
> +
> +void set_huge_pte_at(struct mm_struct *mm,
> +		     unsigned long addr,
> +		     pte_t *ptep,
> +		     pte_t pte)
> +{
> +	int i;
> +	int pte_num;
> +
> +	if (!pte_napot(pte)) {
> +		set_pte_at(mm, addr, ptep, pte);
> +		return;
> +	}
> +
> +	pte_num = napot_pte_num(pte);
> +	for (i = 0; i < pte_num; i++, ptep++, addr += PAGE_SIZE)
> +		set_pte_at(mm, addr, ptep, pte);
> +}
> +
> +int huge_ptep_set_access_flags(struct vm_area_struct *vma,
> +			       unsigned long addr,
> +			       pte_t *ptep,
> +			       pte_t pte,
> +			       int dirty)
> +{
> +	pte_t orig_pte;
> +	int i;
> +	int pte_num;
> +
> +	if (!pte_napot(pte))
> +		return ptep_set_access_flags(vma, addr, ptep, pte, dirty);
> +
> +	pte_num = napot_pte_num(pte);
> +	ptep = huge_pte_offset(vma->vm_mm, addr, NAPOT_CONT64KB_SIZE);
> +	orig_pte = huge_ptep_get(ptep);
> +
> +	if (pte_dirty(orig_pte))
> +		pte = pte_mkdirty(pte);
> +
> +	if (pte_young(orig_pte))
> +		pte = pte_mkyoung(pte);
> +
> +	for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++)
> +		ptep_set_access_flags(vma, addr, ptep, pte, dirty);
> +
> +	return true;
> +}
> +
> +pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
> +			      unsigned long addr,
> +			      pte_t *ptep)
> +{
> +	int pte_num;
> +	pte_t orig_pte = huge_ptep_get(ptep);
> +
> +	if (!pte_napot(orig_pte))
> +		return ptep_get_and_clear(mm, addr, ptep);
> +
> +	pte_num = napot_pte_num(orig_pte);
> +	return get_clear_flush(mm, addr, ptep, pte_num);
> +}
> +
> +void huge_ptep_set_wrprotect(struct mm_struct *mm,
> +			     unsigned long addr,
> +			     pte_t *ptep)
> +{
> +	int i;
> +	int pte_num;
> +	pte_t pte = READ_ONCE(*ptep);
> +
> +	if (!pte_napot(pte))
> +		return ptep_set_wrprotect(mm, addr, ptep);
> +
> +	pte_num = napot_pte_num(pte);
> +	ptep = huge_pte_offset(mm, addr, NAPOT_CONT64KB_SIZE);
> +
> +	for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++)
> +		ptep_set_wrprotect(mm, addr, ptep);
> +}
> +
> +pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
> +			    unsigned long addr,
> +			    pte_t *ptep)
> +{
> +	int pte_num;
> +	pte_t pte = READ_ONCE(*ptep);
> +
> +	if (!pte_napot(pte)) {
> +		ptep_clear_flush(vma, addr, ptep);
> +		return pte;
> +	}
> +
> +	pte_num = napot_pte_num(pte);
> +	clear_flush(vma->vm_mm, addr, ptep, pte_num);
> +
> +	return pte;
> +}
> +
> +void huge_pte_clear(struct mm_struct *mm,
> +		    unsigned long addr,
> +		    pte_t *ptep,
> +		    unsigned long sz)
> +{
> +	int i, pte_num;
> +
> +	pte_num = napot_pte_num(READ_ONCE(*ptep));
> +	for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++)
> +		pte_clear(mm, addr, ptep);
> +}
> +
> +void riscv_set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr,
> +				pte_t *ptep, pte_t pte, unsigned long sz)
> +{
> +	int i, pte_num;
> +
> +	pte_num = napot_pte_num(READ_ONCE(*ptep));
> +
> +	for (i = 0; i < pte_num; i++, ptep++)
> +		set_pte(ptep, pte);
> +}
> +#endif /*CONFIG_RISCV_ISA_SVNAPOT*/
> +
>  int pud_huge(pud_t pud)
>  {
>  	return pud_leaf(pud);
> @@ -18,17 +251,26 @@ bool __init arch_hugetlb_valid_size(unsigned long size)
>  		return true;
>  	else if (IS_ENABLED(CONFIG_64BIT) && size == PUD_SIZE)
>  		return true;
> +#ifdef CONFIG_RISCV_ISA_SVNAPOT
> +	else if (has_svnapot() && size == NAPOT_CONT64KB_SIZE)
> +		return true;
> +#endif /*CONFIG_RISCV_ISA_SVNAPOT*/
>  	else
>  		return false;
>  }
>  
> -#ifdef CONFIG_CONTIG_ALLOC
> -static __init int gigantic_pages_init(void)
> +static __init int hugetlbpage_init(void)
>  {
> +#ifdef CONFIG_CONTIG_ALLOC
>  	/* With CONTIG_ALLOC, we can allocate gigantic pages at runtime */
>  	if (IS_ENABLED(CONFIG_64BIT))
>  		hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
> +#endif /*CONFIG_CONTIG_ALLOC*/
> +	hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
> +#ifdef CONFIG_RISCV_ISA_SVNAPOT
> +	if (has_svnapot())
> +		hugetlb_add_hstate(NAPOT_CONT64KB_SHIFT - PAGE_SHIFT);
> +#endif /*CONFIG_RISCV_ISA_SVNAPOT*/
>  	return 0;
>  }
> -arch_initcall(gigantic_pages_init);
> -#endif
> +arch_initcall(hugetlbpage_init);
> -- 
> 2.35.1
> 
> 
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