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From: Anshuman Khandual <anshuman.khandual@arm.com>
To: Gavin Shan <gshan@redhat.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 07/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in PTE modifying tests
Date: Fri, 23 Jul 2021 08:09:32 +0530	[thread overview]
Message-ID: <492c96ea-5f60-2720-7da8-1fc18a1f95d3@arm.com> (raw)
In-Reply-To: <99c73652-7294-17ff-0c4f-986b588ab022@redhat.com>



On 7/22/21 12:07 PM, Gavin Shan wrote:
> 
>>>         pgdp = pgd_offset(mm, vaddr);
>>>       p4dp = p4d_alloc(mm, pgdp, vaddr);
>>> @@ -1272,11 +1275,11 @@ static int __init debug_vm_pgtable(void)
>>>        * Page table modifying tests. They need to hold
>>>        * proper page table lock.
>>>        */
>>> -
>>> -    ptep = pte_offset_map_lock(mm, pmdp, vaddr, &ptl);
>>> -    pte_clear_tests(mm, ptep, pte_aligned, vaddr, prot);
>>> -    pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
>>> -    pte_unmap_unlock(ptep, ptl);
>>> +    ptl = pte_lockptr(args.mm, args.pmdp);
>>> +    spin_lock(ptl);
>>> +    pte_clear_tests(&args);
>>> +    pte_advanced_tests(&args);
>>> +    spin_unlock(ptl);
>>
>> Why pte_offset_map_lock()/pte_unmap_unlock() has been dropped and
>> spin_lock()/spin_unlock() sequence has been added ? Please dont
>> change the tests in these patches.
>>
> 
> The semantics of pte_offset_map_lock() is to grab and take the lock
> and return the PTE entry, which is mapped if needed. We already had
> the PTE entry tracked by args->ptep in init_args(). So some of the
> operations covered by pte_offset_map_lock() isn't needed any more

To keep the patch on purpose, please avoid this change here. But if
required, you could send a follow up patch later.


  reply	other threads:[~2021-07-23  2:38 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 [this message]
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
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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