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 16/16] debug_vm_pgtable/ppc64: Add a variant of pfn_pte/pmd
Date: Thu, 13 Aug 2020 12:07:42 +0530 [thread overview]
Message-ID: <b42822c9-f8b6-55cf-7bc6-6def2faeb378@linux.ibm.com> (raw)
In-Reply-To: <fe7beb39-97e6-dd7c-59d4-e1a72bab3d71@arm.com>
On 8/13/20 11:00 AM, Anshuman Khandual wrote:
>
> On 08/12/2020 12:03 PM, Aneesh Kumar K.V wrote:
>> The tests do expect _PAGE_PTE bit set by different page table accessors.
>> This is not true for the kernel. Within the kernel, _PAGE_PTE bits are
>> usually set by set_pte_at(). To make the below tests work correctly add test
>> specific pfn_pte/pmd helpers that set _PAGE_PTE bit.
>>
>> pte_t pte = pfn_pte(pfn, prot);
>> WARN_ON(!pte_devmap(pte_mkdevmap(pte)));
>> WARN_ON(!pte_savedwrite(pte_mk_savedwrite(pte_clear_savedwrite(pte))));
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>> ---
>> mm/debug_vm_pgtable.c | 65 +++++++++++++++++++++++++++----------------
>> 1 file changed, 41 insertions(+), 24 deletions(-)
>>
>> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
>> index eea62d5e503b..153c925b5273 100644
>> --- a/mm/debug_vm_pgtable.c
>> +++ b/mm/debug_vm_pgtable.c
>> @@ -31,6 +31,23 @@
>> #include <asm/pgalloc.h>
>> #include <asm/tlbflush.h>
>>
>> +#ifdef CONFIG_PPC_BOOK3S_64
>> +static inline pte_t debug_vm_pfn_pte(unsigned long pfn, pgprot_t pgprot)
>> +{
>> + pte_t pte = pfn_pte(pfn, pgprot);
>> + return __pte(pte_val(pte) | _PAGE_PTE);
>> +
>> +}
>> +static inline pmd_t debug_vm_pfn_pmd(unsigned long pfn, pgprot_t pgprot)
>> +{
>> + pmd_t pmd = pfn_pmd(pfn, pgprot);
>> + return __pmd(pmd_val(pmd) | _PAGE_PTE);
>> +}
>> +#else
>> +#define debug_vm_pfn_pte(pfn, pgprot) pfn_pte(pfn, pgprot)
>> +#define debug_vm_pfn_pmd(pfn, pgprot) pfn_pmd(pfn, pgprot)
>> +#endif
>
> Again, no platform specific constructs please. This defeats the whole purpose of
> this test. If __PAGE_PTE is required for the helpers, then pfn_pmd/pte() could
> be modified to accommodate that. We dont see similar issues on other platforms,
> hence could you please explain why ppc64 is different here.
>
It is not platform specific. set_pte_at is the one that set the
_PAGE_PTE bit. We don't call that in the test. The test seems to make
the assumption that pfn_pte returns a proper pte which is not true.
-aneesh
next prev parent reply other threads:[~2020-08-13 6:40 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
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 [this message]
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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