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SubjectRe: [PATCH v2 00/12] mm/debug_vm_pgtable: Enhancements
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Hi Anshuman,

On 7/19/21 3:41 PM, Gavin Shan wrote:
> There are couple of issues with current implementations and this series
> tries to resolve the issues:
>
> (a) All needed information are scattered in variables, passed to various
> test functions. The code is organized in pretty much relaxed fashion.
>
> (b) The page isn't allocated from buddy during page table entry modifying
> tests. The page can be invalid, conflicting to the implementations
> of set_xxx_at() on ARM64. The target page is accessed so that the iCache
> can be flushed when execution permission is given on ARM64. Besides,
> the target page can be unmapped and access to it causes kernel crash.
>
> "struct pgtable_debug_args" is introduced to address issue (a). For issue
> (b), the used page is allocated from buddy in page table entry modifying
> tests. The corresponding tets will be skipped if we fail to allocate the
> (huge) page. For other test cases, the original page around to kernel
> symbol (@start_kernel) is still used.
>
> The patches are organized as below. PATCH[2-10] could be combined to one
> patch, but it will make the review harder:
>
> PATCH[1] introduces "struct pgtable_debug_args" as place holder of all
> needed information. With it, the old and new implementation
> can coexist.
> PATCH[2-10] uses "struct pgtable_debug_args" in various test functions.
> PATCH[11] removes the old implementation.
> PATCH[12] fixes the issue of corrupted page flag for ARM64
>
> Changelog
> =========
> v2:
> * Rename struct vm_pgtable_debug to struct pgtable_debug_args.
> The parameter name to various test functions are renamed
> to "@args" (Anshuman)
> * Code changes as suggested by Anshuman (Anshuman)
>

Please ignore v2. I will post v3 to fix couple of issues in v2:

(1) The subjects of PATCH[5/12] and PATCH[9/12] should be fixed to
start with "mm/debug_vm_pgtable".
(2) "WARN_ON(!pud_none(pud))" is missed in PATCH[9/12]. Otherwise,
build warning for unused variable @pud is raised.
(3) Build warnings for unused variables in separate patches are
raised, reported by 0-DAY CI Kernel Test Service.

Thanks,
Gavin

> Gavin Shan (12):
> mm/debug_vm_pgtable: Introduce struct pgtable_debug_args
> mm/debug_vm_pgtable: Use struct pgtable_debug_args in basic tests
> mm/debug_vm_pgtable: Use struct pgtable_debug_args in leaf and
> savewrite tests
> mm/debug_vm_pgtable: Use struct pgtable_debug_args in protnone and
> devmap tests
> mm/vm_debug_pgtable: Use struct pgtable_debug_args in soft_dirty and
> swap tests
> mm/debug_vm_pgtable: Use struct pgtable_debug_args in migration and
> thp tests
> mm/debug_vm_pgtable: Use struct pgtable_debug_args in PTE modifying
> tests
> mm/debug_vm_pgtable: Use struct pgtable_debug_args in PMD
> mm/vm_debug_pgtable: Use struct pgtable_debug_args in PUD modifying
> tests
> mm/debug_vm_pgtable: Use struct pgtable_debug_args in PGD and P4D
> modifying tests
> mm/debug_vm_pgtable: Remove unused code
> mm/debug_vm_pgtable: Fix corrupted page flag
>
> mm/debug_vm_pgtable.c | 849 ++++++++++++++++++++++++------------------
> 1 file changed, 479 insertions(+), 370 deletions(-)
>

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