From: Gavin Shan <gshan@redhat.com>
To: Anshuman Khandual <anshuman.khandual@arm.com>, linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org, catalin.marinas@arm.com,
will@kernel.org, akpm@linux-foundation.org, chuhu@redhat.com,
shan.gavin@gmail.com
Subject: Re: [PATCH v3 09/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in PUD modifying tests
Date: Thu, 22 Jul 2021 16:47:27 +1000 [thread overview]
Message-ID: <49ced5c2-5001-9cb7-663e-0d0845f1890a@redhat.com> (raw)
In-Reply-To: <8997bf56-ff67-060d-c25b-91e11f31e88a@arm.com>
Hi Anshuman,
On 7/22/21 3:39 PM, Anshuman Khandual wrote:
> On 7/19/21 6:36 PM, Gavin Shan wrote:
>> This uses struct pgtable_debug_args in PUD modifying tests. The allocated
>> huge page is used when set_pud_at() is used. The corresponding tests
>> are skipped if the huge page doesn't exist. Besides, the following unused
>> variables in debug_vm_pgtable() are dropped: @prot, @paddr, @pud_aligned.
>
> Please dont drop @prot, @paddr, @pud_aligned just yet.
>
Otherwise it will cause build warning ("unused variable") as
explain in previous reply.
>>
>> Signed-off-by: Gavin Shan <gshan@redhat.com>
>> ---
>> mm/debug_vm_pgtable.c | 130 ++++++++++++++++--------------------------
>> 1 file changed, 50 insertions(+), 80 deletions(-)
>>
>> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
>> index cec3cbf99a6b..57b7ead0708b 100644
>> --- a/mm/debug_vm_pgtable.c
>> +++ b/mm/debug_vm_pgtable.c
>> @@ -338,55 +338,55 @@ static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx)
>> WARN_ON(!pud_bad(pud_mkhuge(pud)));
>> }
>>
>> -static void __init pud_advanced_tests(struct mm_struct *mm,
>> - struct vm_area_struct *vma, pud_t *pudp,
>> - unsigned long pfn, unsigned long vaddr,
>> - pgprot_t prot)
>> +static void __init pud_advanced_tests(struct pgtable_debug_args *args)
>> {
>> + unsigned long vaddr = (args->vaddr & HPAGE_PUD_MASK);
>> pud_t pud;
>>
>> if (!has_transparent_hugepage())
>> return;
>>
>> pr_debug("Validating PUD advanced\n");
>> - /* Align the address wrt HPAGE_PUD_SIZE */
>> - vaddr &= HPAGE_PUD_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->pud_pfn == ULONG_MAX) {
>> + pr_debug("%s: Skipped\n", __func__);
>
> Just return. Please dont call out "Skipped". Applicable for all transition
> patches here.
>
Ok.
>> + return;
>> + }
>>
>> - pud = pfn_pud(pfn, prot);
>> - set_pud_at(mm, vaddr, pudp, pud);
>> - pudp_set_wrprotect(mm, vaddr, pudp);
>> - pud = READ_ONCE(*pudp);
>> + pud = pfn_pud(args->pud_pfn, args->page_prot);
>> + set_pud_at(args->mm, vaddr, args->pudp, pud);
>> + pudp_set_wrprotect(args->mm, vaddr, args->pudp);
>> + pud = READ_ONCE(*(args->pudp));
>
> Seems like an extra braces while de-referencing arg->pudp. Could these be
> dropped. Just READ_ONCE(*args->pudp).
>
Ok. Will be dropped in v4.
>> WARN_ON(pud_write(pud));
>>
>> #ifndef __PAGETABLE_PMD_FOLDED
>> - pudp_huge_get_and_clear(mm, vaddr, pudp);
>> - pud = READ_ONCE(*pudp);
>> + pudp_huge_get_and_clear(args->mm, vaddr, args->pudp);
>> + pud = READ_ONCE(*(args->pudp));
>> WARN_ON(!pud_none(pud));
>> #endif /* __PAGETABLE_PMD_FOLDED */
>> - pud = pfn_pud(pfn, prot);
>> + pud = pfn_pud(args->pud_pfn, args->page_prot);
>> pud = pud_wrprotect(pud);
>> pud = pud_mkclean(pud);
>> - set_pud_at(mm, vaddr, pudp, pud);
>> + set_pud_at(args->mm, vaddr, args->pudp, pud);
>> pud = pud_mkwrite(pud);
>> pud = pud_mkdirty(pud);
>> - pudp_set_access_flags(vma, vaddr, pudp, pud, 1);
>> - pud = READ_ONCE(*pudp);
>> + pudp_set_access_flags(args->vma, vaddr, args->pudp, pud, 1);
>> + pud = READ_ONCE(*(args->pudp));
>> WARN_ON(!(pud_write(pud) && pud_dirty(pud)));
>>
>> #ifndef __PAGETABLE_PMD_FOLDED
>> - pudp_huge_get_and_clear_full(mm, vaddr, pudp, 1);
>> - pud = READ_ONCE(*pudp);
>> + pudp_huge_get_and_clear_full(args->mm, vaddr, args->pudp, 1);
>> + pud = READ_ONCE(*(args->pudp));
>> WARN_ON(!pud_none(pud));
>> #endif /* __PAGETABLE_PMD_FOLDED */
>>
>> - pud = pfn_pud(pfn, prot);
>> + pud = pfn_pud(args->pud_pfn, args->page_prot);
>> pud = pud_mkyoung(pud);
>> - set_pud_at(mm, vaddr, pudp, pud);
>> - pudp_test_and_clear_young(vma, vaddr, pudp);
>> - pud = READ_ONCE(*pudp);
>> + set_pud_at(args->mm, vaddr, args->pudp, pud);
>> + pudp_test_and_clear_young(args->vma, vaddr, args->pudp);
>> + pud = READ_ONCE(*(args->pudp));
>> WARN_ON(pud_young(pud));
>>
>> - pudp_huge_get_and_clear(mm, vaddr, pudp);
>> + pudp_huge_get_and_clear(args->mm, vaddr, args->pudp);
>> }
>>
>> static void __init pud_leaf_tests(struct pgtable_debug_args *args)
>> @@ -406,24 +406,14 @@ static void __init pud_leaf_tests(struct pgtable_debug_args *args)
>> }
>> #else /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
>> static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx) { }
>> -static void __init pud_advanced_tests(struct mm_struct *mm,
>> - struct vm_area_struct *vma, pud_t *pudp,
>> - unsigned long pfn, unsigned long vaddr,
>> - pgprot_t prot)
>> -{
>> -}
>> +static void __init pud_advanced_tests(struct pgtable_debug_args *args) { }
>> static void __init pud_leaf_tests(struct pgtable_debug_args *args) { }
>> #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
>> #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 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,
>> - pgprot_t prot)
>> -{
>> -}
>> +static void __init pud_advanced_tests(struct pgtable_debug_args *args) { }
>> static void __init pmd_leaf_tests(struct pgtable_debug_args *args) { }
>> static void __init pud_leaf_tests(struct pgtable_debug_args *args) { }
>> static void __init pmd_savedwrite_tests(struct pgtable_debug_args *args) { }
>> @@ -450,11 +440,11 @@ static void __init pmd_huge_tests(struct pgtable_debug_args *args)
>> WARN_ON(!pmd_none(pmd));
>> }
>>
>> -static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
>> +static void __init pud_huge_tests(struct pgtable_debug_args *args)
>> {
>> pud_t pud;
>>
>> - if (!arch_vmap_pud_supported(prot))
>> + if (!arch_vmap_pud_supported(args->page_prot))
>> return;
>>
>> pr_debug("Validating PUD huge\n");
>> @@ -462,15 +452,16 @@ static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
>> * X86 defined pud_set_huge() verifies that the given
>> * PUD is not a populated non-leaf entry.
>> */
>> - WRITE_ONCE(*pudp, __pud(0));
>> - WARN_ON(!pud_set_huge(pudp, __pfn_to_phys(pfn), prot));
>> - WARN_ON(!pud_clear_huge(pudp));
>> - pud = READ_ONCE(*pudp);
>> + WRITE_ONCE(*(args->pudp), __pud(0));
>> + WARN_ON(!pud_set_huge(args->pudp, __pfn_to_phys(args->fixed_pud_pfn),
>> + args->page_prot));
>
> Please dont break the line, we could go upto 100 width. Please do
> the same for the entire series. Improves the readability.
>
>> + WARN_ON(!pud_clear_huge(args->pudp));
>> + pud = READ_ONCE(*(args->pudp));
>> WARN_ON(!pud_none(pud));
>> }
>> #else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
>> 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) { }
>> +static void __init pud_huge_tests(struct pgtable_debug_args *args) { }
>> #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
>>
>> static void __init p4d_basic_tests(void)
>> @@ -492,27 +483,26 @@ static void __init pgd_basic_tests(void)
>> }
>>
>> #ifndef __PAGETABLE_PUD_FOLDED
>> -static void __init pud_clear_tests(struct mm_struct *mm, pud_t *pudp)
>> +static void __init pud_clear_tests(struct pgtable_debug_args *args)
>> {
>> - pud_t pud = READ_ONCE(*pudp);
>> + pud_t pud = READ_ONCE(*(args->pudp));
>>
>> - if (mm_pmd_folded(mm))
>> + if (mm_pmd_folded(args->mm))
>> return;
>>
>> pr_debug("Validating PUD clear\n");
>> pud = __pud(pud_val(pud) | RANDOM_ORVALUE);
>> - WRITE_ONCE(*pudp, pud);
>> - pud_clear(pudp);
>> - pud = READ_ONCE(*pudp);
>> + WRITE_ONCE(*(args->pudp), pud);
>> + pud_clear(args->pudp);
>> + pud = READ_ONCE(*(args->pudp));
>> WARN_ON(!pud_none(pud));
>> }
>>
>> -static void __init pud_populate_tests(struct mm_struct *mm, pud_t *pudp,
>> - pmd_t *pmdp)
>> +static void __init pud_populate_tests(struct pgtable_debug_args *args)
>> {
>> pud_t pud;
>>
>> - if (mm_pmd_folded(mm))
>> + if (mm_pmd_folded(args->mm))
>> return;
>>
>> pr_debug("Validating PUD populate\n");
>> @@ -520,16 +510,13 @@ static void __init pud_populate_tests(struct mm_struct *mm, pud_t *pudp,
>> * This entry points to next level page table page.
>> * Hence this must not qualify as pud_bad().
>> */
>> - pud_populate(mm, pudp, pmdp);
>> - pud = READ_ONCE(*pudp);
>> + pud_populate(args->mm, args->pudp, args->start_pmdp);
>> + pud = READ_ONCE(*(args->pudp));
>> WARN_ON(pud_bad(pud));
>> }
>> #else /* !__PAGETABLE_PUD_FOLDED */
>> -static void __init pud_clear_tests(struct mm_struct *mm, pud_t *pudp) { }
>> -static void __init pud_populate_tests(struct mm_struct *mm, pud_t *pudp,
>> - pmd_t *pmdp)
>> -{
>> -}
>> +static void __init pud_clear_tests(struct pgtable_debug_args *args) { }
>> +static void __init pud_populate_tests(struct pgtable_debug_args *args) { }
>> #endif /* PAGETABLE_PUD_FOLDED */
>>
>> #ifndef __PAGETABLE_P4D_FOLDED
>> @@ -1152,10 +1139,7 @@ static int __init debug_vm_pgtable(void)
>> pud_t *pudp, *saved_pudp;
>> pmd_t *pmdp, *saved_pmdp, pmd;
>> pgtable_t saved_ptep;
>> - pgprot_t prot;
>> - phys_addr_t paddr;
>> unsigned long vaddr;
>> - unsigned long pud_aligned;
>> spinlock_t *ptl = NULL;
>> int idx, ret;
>>
>> @@ -1164,7 +1148,6 @@ static int __init debug_vm_pgtable(void)
>> if (ret)
>> return ret;
>>
>> - prot = vm_get_page_prot(VMFLAGS);
>
> Please dont drop these just yet and wait until [PATCH 11/12].
>
>> vaddr = get_random_vaddr();
>> mm = mm_alloc();
>> if (!mm) {
>> @@ -1178,19 +1161,6 @@ static int __init debug_vm_pgtable(void)
>> return 1;
>> }
>>
>> - /*
>> - * PFN for mapping at PTE level is determined from a standard kernel
>> - * text symbol. But pfns for higher page table levels are derived by
>> - * masking lower bits of this real pfn. These derived pfns might not
>> - * exist on the platform but that does not really matter as pfn_pxx()
>> - * helpers will still create appropriate entries for the test. This
>> - * helps avoid large memory block allocations to be used for mapping
>> - * at higher page table levels.
>> - */
>
> Please move this comment as is to the right place inside init_args()
> in the first patch itself. If possible all comments should be moved
> during the first patch and just the code remains till [PATCH 11/12].
>
I will include all comments in PATCH[01/12]. In that case, we won't
introduce more changes to unrelated function (init_args()).
>> - paddr = __pa_symbol(&start_kernel);
>> -
>> - pud_aligned = (paddr & PUD_MASK) >> PAGE_SHIFT;
>> -
>
> Please dont drop these just yet and wait until [PATCH 11/12].
>
Otherwise, it will cause build warning.
>> pgdp = pgd_offset(mm, vaddr);
>> p4dp = p4d_alloc(mm, pgdp, vaddr);
>> pudp = pud_alloc(mm, p4dp, vaddr);
>> @@ -1282,11 +1252,11 @@ static int __init debug_vm_pgtable(void)
>> pmd_populate_tests(&args);
>> spin_unlock(ptl);
>>
>> - ptl = pud_lock(mm, pudp);
>> - pud_clear_tests(mm, pudp);
>> - pud_advanced_tests(mm, vma, pudp, pud_aligned, vaddr, prot);
>> - pud_huge_tests(pudp, pud_aligned, prot);
>> - pud_populate_tests(mm, pudp, saved_pmdp);
>> + ptl = pud_lock(args.mm, args.pudp);
>> + pud_clear_tests(&args);
>> + pud_advanced_tests(&args);
>> + pud_huge_tests(&args);
>> + pud_populate_tests(&args);
>> spin_unlock(ptl);
>>
>> spin_lock(&mm->page_table_lock);
>>
>
Thanks,
Gavin
next prev parent reply other threads:[~2021-07-22 6:47 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-19 13:06 [PATCH v3 00/12] mm/debug_vm_pgtable: Enhancements Gavin Shan
2021-07-19 13:06 ` [PATCH v3 01/12] mm/debug_vm_pgtable: Introduce struct pgtable_debug_args Gavin Shan
2021-07-21 5:44 ` Anshuman Khandual
2021-07-21 10:20 ` Gavin Shan
2021-07-21 10:39 ` Anshuman Khandual
2021-07-21 10:59 ` Anshuman Khandual
2021-07-21 11:59 ` Gavin Shan
2021-07-22 4:41 ` Anshuman Khandual
2021-07-22 6:23 ` Gavin Shan
2021-07-22 7:08 ` Anshuman Khandual
2021-07-23 0:43 ` Gavin Shan
2021-07-19 13:06 ` [PATCH v3 02/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in basic tests Gavin Shan
2021-07-21 5:57 ` Anshuman Khandual
2021-07-21 11:57 ` Gavin Shan
2021-07-19 13:06 ` [PATCH v3 03/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in leaf and savewrite tests Gavin Shan
2021-07-19 13:06 ` [PATCH v3 04/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in protnone and devmap tests Gavin Shan
2021-07-19 13:06 ` [PATCH v3 05/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in soft_dirty and swap tests Gavin Shan
2021-07-19 13:06 ` [PATCH v3 06/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in migration and thp tests Gavin Shan
2021-07-19 13:06 ` [PATCH v3 07/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in PTE modifying tests Gavin Shan
2021-07-22 5:56 ` Anshuman Khandual
2021-07-22 6:37 ` Gavin Shan
2021-07-23 2:39 ` Anshuman Khandual
2021-07-23 4:23 ` Gavin Shan
2021-07-19 13:06 ` [PATCH v3 08/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in PMD " Gavin Shan
2021-07-22 5:45 ` Anshuman Khandual
2021-07-22 6:41 ` Gavin Shan
2021-07-22 7:11 ` Anshuman Khandual
2021-07-23 1:00 ` Gavin Shan
2021-07-23 2:33 ` Anshuman Khandual
2021-07-19 13:06 ` [PATCH v3 09/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in PUD " Gavin Shan
2021-07-22 5:39 ` Anshuman Khandual
2021-07-22 6:47 ` Gavin Shan [this message]
2021-07-19 13:06 ` [PATCH v3 10/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in PGD and P4D " Gavin Shan
2021-07-22 5:09 ` Anshuman Khandual
2021-07-22 6:50 ` Gavin Shan
2021-07-19 13:06 ` [PATCH v3 11/12] mm/debug_vm_pgtable: Remove unused code Gavin Shan
2021-07-22 4:51 ` Anshuman Khandual
2021-07-22 6:53 ` Gavin Shan
2021-07-19 13:06 ` [PATCH v3 12/12] mm/debug_vm_pgtable: Fix corrupted page flag Gavin Shan
2021-07-21 10:18 ` Anshuman Khandual
2021-07-21 12:03 ` Gavin Shan
2021-07-22 3:51 ` Anshuman Khandual
2021-07-22 6:54 ` Gavin Shan
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