From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: Anshuman Khandual <anshuman.khandual@arm.com>,
linux-mm@kvack.org, akpm@linux-foundation.org
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 10/16] debug_vm_pgtable/thp: Use page table depost/withdraw with THP
Date: Thu, 13 Aug 2020 12:08:51 +0530 [thread overview]
Message-ID: <bb3821c4-0d23-e6a6-33ad-6c0e3ad67644@linux.ibm.com> (raw)
In-Reply-To: <40f2acb5-1da3-4c0a-5590-3fd12d128421@arm.com>
On 8/13/20 10:55 AM, Anshuman Khandual wrote:
> On 08/12/2020 12:03 PM, Aneesh Kumar K.V wrote:
>> Architectures like ppc64 use deposited page table while updating the huge pte
>> entries.
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>> ---
>> mm/debug_vm_pgtable.c | 8 ++++++--
>> 1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
>> index 644d28861ce9..48475d288df1 100644
>> --- a/mm/debug_vm_pgtable.c
>> +++ b/mm/debug_vm_pgtable.c
>> @@ -147,7 +147,7 @@ static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot)
>> 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)
>> + pgprot_t prot, pgtable_t pgtable)
>> {
>> pmd_t pmd;
>>
>> @@ -158,6 +158,8 @@ static void __init pmd_advanced_tests(struct mm_struct *mm,
>> /* Align the address wrt HPAGE_PMD_SIZE */
>> vaddr = (vaddr & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE;
>>
>> + pgtable_trans_huge_deposit(mm, pmdp, pgtable);
>> +
>> pmd = pmd_mkhuge(pfn_pmd(pfn, prot));
>> set_pmd_at(mm, vaddr, pmdp, pmd);
>> pmdp_set_wrprotect(mm, vaddr, pmdp);
>> @@ -188,6 +190,8 @@ static void __init pmd_advanced_tests(struct mm_struct *mm,
>> pmdp_test_and_clear_young(vma, vaddr, pmdp);
>> pmd = READ_ONCE(*pmdp);
>> WARN_ON(pmd_young(pmd));
>> +
>> + pgtable = pgtable_trans_huge_withdraw(mm, pmdp);
>> }
>>
>> static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot)
>> @@ -1002,7 +1006,7 @@ static int __init debug_vm_pgtable(void)
>> pgd_clear_tests(mm, pgdp);
>>
>> pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
>> - pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot);
>> + pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot, saved_ptep);
>> pud_advanced_tests(mm, vma, pudp, pud_aligned, vaddr, prot);
>> hugetlb_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
>>
>>
>
> Makes sense, if it is required for THP to work correctly but needs to be tested
> across enabled platforms. Why should not the same apply for pud_advanced_tests()
> on platforms that supports PUD based THP.
>
pud doesn't have page table deposit/withdraw semantics. We use that to
support hugepage split. With pud mapping we don't split, we just drop
the hugepage and expect it to be faulted back in as regular page.
-aneesh
next prev parent reply other threads:[~2020-08-13 6:42 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-12 6:33 [PATCH 01/16] powerpc/mm: Add DEBUG_VM WARN for pmd_clear Aneesh Kumar K.V
2020-08-12 6:33 ` [PATCH 02/16] debug_vm_pgtable/ppc64: Avoid setting top bits in radom value Aneesh Kumar K.V
2020-08-12 6:40 ` Christophe Leroy
2020-08-12 6:43 ` Aneesh Kumar K.V
2020-08-12 8:12 ` Anshuman Khandual
2020-08-12 8:25 ` Aneesh Kumar K.V
2020-08-12 6:33 ` [PATCH 03/16] debug_vm_pgtable/set_pte: Don't use set_pte_at to update an existing pte entry Aneesh Kumar K.V
2020-08-12 9:12 ` Anshuman Khandual
2020-08-12 9:22 ` Aneesh Kumar K.V
2020-08-12 6:33 ` [PATCH 04/16] debug_vm_pgtables/hugevmap: Use the arch helper to identify huge vmap support Aneesh Kumar K.V
2020-08-12 10:30 ` Anshuman Khandual
2020-08-12 6:33 ` [PATCH 05/16] debug_vm_pgtable/savedwrite: Enable savedwrite test with CONFIG_NUMA_BALANCING Aneesh Kumar K.V
2020-08-12 11:24 ` Anshuman Khandual
2020-08-12 6:33 ` [PATCH 06/16] debug_vm_pgtable/THP: Mark the pte entry huge before using set_pmd_at Aneesh Kumar K.V
2020-08-12 6:33 ` [PATCH 07/16] debug_vm_pgtable/THP: Mark the pte entry huge before using set_pud_at Aneesh Kumar K.V
2020-08-12 11:49 ` Anshuman Khandual
2020-08-12 6:33 ` [PATCH 08/16] debug_vm_pgtable/set_pmd: Don't use set_pmd_at to update an existing pmd entry Aneesh Kumar K.V
2020-08-12 12:46 ` Anshuman Khandual
2020-08-12 6:33 ` [PATCH 09/16] debug_vm_pgtable/set_pud: Don't use set_pud_at to update an existing pud entry Aneesh Kumar K.V
2020-08-12 12:46 ` Anshuman Khandual
2020-08-12 6:33 ` [PATCH 10/16] debug_vm_pgtable/thp: Use page table depost/withdraw with THP Aneesh Kumar K.V
2020-08-13 5:25 ` Anshuman Khandual
2020-08-13 6:38 ` Aneesh Kumar K.V [this message]
2020-08-12 6:33 ` [PATCH 11/16] debug_vm_pgtable/locks: Move non page table modifying test together Aneesh Kumar K.V
2020-08-12 6:33 ` [PATCH 12/16] debug_vm_pgtable/locks: Take correct page table lock Aneesh Kumar K.V
2020-08-12 6:33 ` [PATCH 13/16] debug_vm_pgtable/pmd_clear: Don't use pmd/pud_clear on pte entries Aneesh Kumar K.V
2020-08-13 5:27 ` Anshuman Khandual
2020-08-13 8:45 ` Aneesh Kumar K.V
2020-08-12 6:33 ` [PATCH 14/16] debug_vm_pgtable/hugetlb: Disable hugetlb test on ppc64 Aneesh Kumar K.V
2020-08-12 13:03 ` Anshuman Khandual
2020-08-12 13:16 ` Aneesh Kumar K.V
2020-08-12 13:34 ` Anshuman Khandual
2020-08-12 13:52 ` Aneesh Kumar K.V
2020-08-14 8:43 ` Anshuman Khandual
2020-08-19 6:54 ` Aneesh Kumar K.V
2020-08-12 6:33 ` [PATCH 15/16] debug_vm_pgtable/savedwrite: Use savedwrite test with protnone ptes Aneesh Kumar K.V
2020-08-12 13:06 ` Anshuman Khandual
2020-08-12 6:33 ` [PATCH 16/16] debug_vm_pgtable/ppc64: Add a variant of pfn_pte/pmd Aneesh Kumar K.V
2020-08-13 5:30 ` Anshuman Khandual
2020-08-13 6:37 ` Aneesh Kumar K.V
2020-08-14 8:29 ` Anshuman Khandual
2020-08-12 7:46 ` [PATCH 01/16] powerpc/mm: Add DEBUG_VM WARN for pmd_clear Anshuman Khandual
2020-08-12 8:27 ` Aneesh Kumar K.V
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