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Message-ID: <e2707943-8645-a6d5-be15-7cf56791fedb@redhat.com>
Date: Thu, 22 Jul 2021 16:41:30 +1000
From: Gavin Shan <gshan@...hat.com>
To: Anshuman Khandual <anshuman.khandual@....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
Hi Anshuman,
On 7/22/21 3:45 PM, Anshuman Khandual wrote:
> 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.
>
We need do so. Otherwise, there is build warning to complain
something like 'unused variable' after this patch is applied.
>>
>> 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.
>
Ok.
>> + if (args->pmd_pfn == ULONG_MAX) {
>> + pr_debug("%s: Skipped\n", __func__);
>> + return;
>> + }
>
> Just return. Please dont call out "Skipped".
>
Ok.
>>
>> - 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.
>
Will drop it in v4, thanks!
>> + WARN_ON(!pmd_set_huge(args->pmdp, __pfn_to_phys(args->fixed_pmd_pfn),
>> + args->page_prot));
>
> Dont break the line.
>
Ok.
>> + 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].
>
Otherwise, it causes build warning: 'unused variable'.
>> 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);
>>
>
Thanks,
Gavin
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