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Message-ID: <52a61d4a-f93d-af9e-4a34-d8ea7c476838@arm.com>
Date: Thu, 22 Jul 2021 11:15:08 +0530
From: Anshuman Khandual <anshuman.khandual@....com>
To: Gavin Shan <gshan@...hat.com>, linux-mm@...ck.org
Cc: linux-kernel@...r.kernel.org, catalin.marinas@....com,
will@...nel.org, akpm@...ux-foundation.org, chuhu@...hat.com,
shan.gavin@...il.com
Subject: Re: [PATCH v3 08/12] mm/debug_vm_pgtable: Use struct
pgtable_debug_args in PMD modifying tests
On 7/19/21 6:36 PM, Gavin Shan wrote:
> This uses struct pgtable_debug_args in PMD modifying tests. The allocated
> huge page is used when set_pmd_at() is used. The corresponding tests
> are skipped if the huge page doesn't exist. Besides, the unused variable
> @pmd_aligned in debug_vm_pgtable() is dropped.
Please dont drop @pmd_aligned just yet.
>
> Signed-off-by: Gavin Shan <gshan@...hat.com>
> ---
> mm/debug_vm_pgtable.c | 102 ++++++++++++++++++++----------------------
> 1 file changed, 48 insertions(+), 54 deletions(-)
>
> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
> index eb6dda88e0d9..cec3cbf99a6b 100644
> --- a/mm/debug_vm_pgtable.c
> +++ b/mm/debug_vm_pgtable.c
> @@ -213,54 +213,54 @@ static void __init pmd_basic_tests(struct pgtable_debug_args *args, int idx)
> WARN_ON(!pmd_bad(pmd_mkhuge(pmd)));
> }
>
> -static void __init pmd_advanced_tests(struct mm_struct *mm,
> - struct vm_area_struct *vma, pmd_t *pmdp,
> - unsigned long pfn, unsigned long vaddr,
> - pgprot_t prot, pgtable_t pgtable)
> +static void __init pmd_advanced_tests(struct pgtable_debug_args *args)
> {
> pmd_t pmd;
> + unsigned long vaddr = (args->vaddr & HPAGE_PMD_MASK);
>
> if (!has_transparent_hugepage())
> return;
>
> pr_debug("Validating PMD advanced\n");
> - /* Align the address wrt HPAGE_PMD_SIZE */
> - vaddr &= HPAGE_PMD_MASK;
Please just leave these unchanged. If has_transparent_hugepage() evaluates
negative, it skips the masking operation. As mentioned earlier please avoid
changing the test in any manner during these transition patches.
> + if (args->pmd_pfn == ULONG_MAX) {
> + pr_debug("%s: Skipped\n", __func__);
> + return;
> + }
Just return. Please dont call out "Skipped".
>
> - pgtable_trans_huge_deposit(mm, pmdp, pgtable);
> + pgtable_trans_huge_deposit(args->mm, args->pmdp, args->start_ptep);
>
> - pmd = pfn_pmd(pfn, prot);
> - set_pmd_at(mm, vaddr, pmdp, pmd);
> - pmdp_set_wrprotect(mm, vaddr, pmdp);
> - pmd = READ_ONCE(*pmdp);
> + pmd = pfn_pmd(args->pmd_pfn, args->page_prot);
> + set_pmd_at(args->mm, vaddr, args->pmdp, pmd);
> + pmdp_set_wrprotect(args->mm, vaddr, args->pmdp);
> + pmd = READ_ONCE(*(args->pmdp));
> WARN_ON(pmd_write(pmd));
> - pmdp_huge_get_and_clear(mm, vaddr, pmdp);
> - pmd = READ_ONCE(*pmdp);
> + pmdp_huge_get_and_clear(args->mm, vaddr, args->pmdp);
> + pmd = READ_ONCE(*(args->pmdp));
> WARN_ON(!pmd_none(pmd));
>
> - pmd = pfn_pmd(pfn, prot);
> + pmd = pfn_pmd(args->pmd_pfn, args->page_prot);
> pmd = pmd_wrprotect(pmd);
> pmd = pmd_mkclean(pmd);
> - set_pmd_at(mm, vaddr, pmdp, pmd);
> + set_pmd_at(args->mm, vaddr, args->pmdp, pmd);
> pmd = pmd_mkwrite(pmd);
> pmd = pmd_mkdirty(pmd);
> - pmdp_set_access_flags(vma, vaddr, pmdp, pmd, 1);
> - pmd = READ_ONCE(*pmdp);
> + pmdp_set_access_flags(args->vma, vaddr, args->pmdp, pmd, 1);
> + pmd = READ_ONCE(*(args->pmdp));
> WARN_ON(!(pmd_write(pmd) && pmd_dirty(pmd)));
> - pmdp_huge_get_and_clear_full(vma, vaddr, pmdp, 1);
> - pmd = READ_ONCE(*pmdp);
> + pmdp_huge_get_and_clear_full(args->vma, vaddr, args->pmdp, 1);
> + pmd = READ_ONCE(*(args->pmdp));
> WARN_ON(!pmd_none(pmd));
>
> - pmd = pmd_mkhuge(pfn_pmd(pfn, prot));
> + pmd = pmd_mkhuge(pfn_pmd(args->pmd_pfn, args->page_prot));
> pmd = pmd_mkyoung(pmd);
> - set_pmd_at(mm, vaddr, pmdp, pmd);
> - pmdp_test_and_clear_young(vma, vaddr, pmdp);
> - pmd = READ_ONCE(*pmdp);
> + set_pmd_at(args->mm, vaddr, args->pmdp, pmd);
> + pmdp_test_and_clear_young(args->vma, vaddr, args->pmdp);
> + pmd = READ_ONCE(*(args->pmdp));
> WARN_ON(pmd_young(pmd));
>
> /* Clear the pte entries */
> - pmdp_huge_get_and_clear(mm, vaddr, pmdp);
> - pgtable = pgtable_trans_huge_withdraw(mm, pmdp);
> + pmdp_huge_get_and_clear(args->mm, vaddr, args->pmdp);
> + pgtable_trans_huge_withdraw(args->mm, args->pmdp);
> }
>
> static void __init pmd_leaf_tests(struct pgtable_debug_args *args)
> @@ -417,12 +417,7 @@ static void __init pud_leaf_tests(struct pgtable_debug_args *args) { }
> #else /* !CONFIG_TRANSPARENT_HUGEPAGE */
> static void __init pmd_basic_tests(struct pgtable_debug_args *args, int idx) { }
> static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx) { }
> -static void __init pmd_advanced_tests(struct mm_struct *mm,
> - struct vm_area_struct *vma, pmd_t *pmdp,
> - unsigned long pfn, unsigned long vaddr,
> - pgprot_t prot, pgtable_t pgtable)
> -{
> -}
> +static void __init pmd_advanced_tests(struct pgtable_debug_args *args) { }
> static void __init pud_advanced_tests(struct mm_struct *mm,
> struct vm_area_struct *vma, pud_t *pudp,
> unsigned long pfn, unsigned long vaddr,
> @@ -435,11 +430,11 @@ static void __init pmd_savedwrite_tests(struct pgtable_debug_args *args) { }
> #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>
> #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
> -static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)
> +static void __init pmd_huge_tests(struct pgtable_debug_args *args)
> {
> pmd_t pmd;
>
> - if (!arch_vmap_pmd_supported(prot))
> + if (!arch_vmap_pmd_supported(args->page_prot))
> return;
>
> pr_debug("Validating PMD huge\n");
> @@ -447,10 +442,11 @@ static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)
> * X86 defined pmd_set_huge() verifies that the given
> * PMD is not a populated non-leaf entry.
> */
> - WRITE_ONCE(*pmdp, __pmd(0));
> - WARN_ON(!pmd_set_huge(pmdp, __pfn_to_phys(pfn), prot));
> - WARN_ON(!pmd_clear_huge(pmdp));
> - pmd = READ_ONCE(*pmdp);
> + WRITE_ONCE(*(args->pmdp), __pmd(0));
Possible extra braces.
> + WARN_ON(!pmd_set_huge(args->pmdp, __pfn_to_phys(args->fixed_pmd_pfn),
> + args->page_prot));
Dont break the line.
> + WARN_ON(!pmd_clear_huge(args->pmdp));
> + pmd = READ_ONCE(*(args->pmdp));
> WARN_ON(!pmd_none(pmd));
> }
>
> @@ -473,7 +469,7 @@ static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
> WARN_ON(!pud_none(pud));
> }
> #else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
> -static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot) { }
> +static void __init pmd_huge_tests(struct pgtable_debug_args *args) { }
> static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot) { }
> #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
>
> @@ -640,20 +636,19 @@ static void __init pte_clear_tests(struct pgtable_debug_args *args)
> WARN_ON(!pte_none(pte));
> }
>
> -static void __init pmd_clear_tests(struct mm_struct *mm, pmd_t *pmdp)
> +static void __init pmd_clear_tests(struct pgtable_debug_args *args)
> {
> - pmd_t pmd = READ_ONCE(*pmdp);
> + pmd_t pmd = READ_ONCE(*(args->pmdp));
>
> pr_debug("Validating PMD clear\n");
> pmd = __pmd(pmd_val(pmd) | RANDOM_ORVALUE);
> - WRITE_ONCE(*pmdp, pmd);
> - pmd_clear(pmdp);
> - pmd = READ_ONCE(*pmdp);
> + WRITE_ONCE(*(args->pmdp), pmd);
> + pmd_clear(args->pmdp);
> + pmd = READ_ONCE(*(args->pmdp));
> WARN_ON(!pmd_none(pmd));
> }
>
> -static void __init pmd_populate_tests(struct mm_struct *mm, pmd_t *pmdp,
> - pgtable_t pgtable)
> +static void __init pmd_populate_tests(struct pgtable_debug_args *args)
> {
> pmd_t pmd;
>
> @@ -662,8 +657,8 @@ static void __init pmd_populate_tests(struct mm_struct *mm, pmd_t *pmdp,
> * This entry points to next level page table page.
> * Hence this must not qualify as pmd_bad().
> */
> - pmd_populate(mm, pmdp, pgtable);
> - pmd = READ_ONCE(*pmdp);
> + pmd_populate(args->mm, args->pmdp, args->start_ptep);
> + pmd = READ_ONCE(*(args->pmdp));
> WARN_ON(pmd_bad(pmd));
> }
>
> @@ -1159,7 +1154,7 @@ static int __init debug_vm_pgtable(void)
> pgtable_t saved_ptep;
> pgprot_t prot;
> phys_addr_t paddr;
> - unsigned long vaddr, pmd_aligned;
> + unsigned long vaddr;
> unsigned long pud_aligned;
> spinlock_t *ptl = NULL;
> int idx, ret;
> @@ -1194,7 +1189,6 @@ static int __init debug_vm_pgtable(void)
> */
> paddr = __pa_symbol(&start_kernel);
>
> - pmd_aligned = (paddr & PMD_MASK) >> PAGE_SHIFT;
Please dont drop these just yet and wait until [PATCH 11/12].
> pud_aligned = (paddr & PUD_MASK) >> PAGE_SHIFT;
>
> pgdp = pgd_offset(mm, vaddr);
> @@ -1281,11 +1275,11 @@ static int __init debug_vm_pgtable(void)
> pte_advanced_tests(&args);
> spin_unlock(ptl);
>
> - ptl = pmd_lock(mm, pmdp);
> - pmd_clear_tests(mm, pmdp);
> - pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot, saved_ptep);
> - pmd_huge_tests(pmdp, pmd_aligned, prot);
> - pmd_populate_tests(mm, pmdp, saved_ptep);
> + ptl = pmd_lock(args.mm, args.pmdp);
> + pmd_clear_tests(&args);
> + pmd_advanced_tests(&args);
> + pmd_huge_tests(&args);
> + pmd_populate_tests(&args);
> spin_unlock(ptl);
>
> ptl = pud_lock(mm, pudp);
>
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