From: "David Hildenbrand (Arm)" <david@kernel•org>
To: Kevin Brodsky <kevin.brodsky@arm•com>,
Vishal Moola <vishal.moola@gmail•com>,
Catalin Marinas <catalin.marinas@arm•com>
Cc: Andrew Morton <akpm@linux-foundation•org>,
Alistair Popple <apopple@nvidia•com>,
linux-arm-kernel@lists•infradead.org,
linux-kernel@vger•kernel.org, linux-mm@kvack•org,
will@kernel•org
Subject: Re: [PATCH] arm64: mm: call pagetable dtor when freeing hot-removed page tables
Date: Tue, 26 May 2026 14:31:01 +0200 [thread overview]
Message-ID: <1be38262-53de-4a27-9841-393e12fc1475@kernel.org> (raw)
In-Reply-To: <92450154-e1ab-46e4-b23d-eaa59c9cdd3b@arm.com>
On 5/26/26 13:54, Kevin Brodsky wrote:
> On 22/05/2026 11:36, Vishal Moola wrote:
>>> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
>>> index 4c8959153ac4..9d42cbddce27 100644
>>> --- a/arch/arm64/mm/mmu.c
>>> +++ b/arch/arm64/mm/mmu.c
>>> @@ -1441,6 +1441,9 @@ static void free_hotplug_page_range(struct page *page, size_t size,
>>>
>>> static void free_hotplug_pgtable_page(struct page *page)
>>> {
>>> + if (folio_test_pgtable(page_folio(page)))
>> This should work.
>>
>>> + pagetable_dtor(page_ptdesc(page));
>>> +
>>> free_hotplug_page_range(page, PAGE_SIZE, NULL);
>> In the case we presumably have a page table page (ptdesc) at this
>> point, we should really be freeing it with pagetable_free() as well.
>
> Agreed, I think this is the right thing to do, something like:
>
> if (folio_test_pgtable(page_folio(page)))
> pagetable_dtor_free(page_ptdesc(page)); else
> free_hotplug_page_range(page, PAGE_SIZE, NULL);
That code pattern is wrong.
folio_test_pgtable() shouldn't exist.
In the future, something is either a pgtable or a folio, not both.
So check the type against the page, not the folio.
--
Cheers,
David
next prev parent reply other threads:[~2026-05-26 12:31 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-21 3:27 [PATCH] arm64: mm: call pagetable dtor when freeing hot-removed page tables Alistair Popple
2026-05-21 22:31 ` Andrew Morton
2026-05-21 23:50 ` Alistair Popple
2026-05-22 7:15 ` Catalin Marinas
2026-05-22 7:32 ` Catalin Marinas
2026-05-22 9:36 ` Vishal Moola
2026-05-26 11:54 ` Kevin Brodsky
2026-05-26 12:31 ` David Hildenbrand (Arm) [this message]
2026-05-27 7:34 ` Kevin Brodsky
2026-05-27 9:22 ` Vishal Moola
2026-05-31 19:29 ` David Hildenbrand (Arm)
2026-05-26 15:07 ` Will Deacon
2026-05-27 7:35 ` Kevin Brodsky
2026-05-27 9:30 ` Vishal Moola
2026-05-28 8:05 ` Kevin Brodsky
2026-05-29 10:16 ` Vishal Moola
2026-06-02 4:22 ` Andrew Morton
2026-06-02 13:12 ` Will Deacon
2026-06-02 17:06 ` Andrew Morton
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