From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Kefeng Wang <wangkefeng.wang@huawei.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Zi Yan <ziy@nvidia.com>, Matthew Brost <matthew.brost@intel.com>,
Joshua Hahn <joshua.hahnjy@gmail.com>,
Rakie Kim <rakie.kim@sk.com>, Byungchul Park <byungchul@sk.com>,
Gregory Price <gourry@gourry.net>,
Ying Huang <ying.huang@linux.alibaba.com>,
Alistair Popple <apopple@nvidia.com>,
linux-mm@kvack.org
Subject: Re: [PATCH] mm: migrate_device: fix pte_pfn/pte_dirty called on non-present PTE
Date: Tue, 7 Jul 2026 15:03:45 +0200 [thread overview]
Message-ID: <56665ebc-a8de-4d59-a4bc-94b42a6b74cf@kernel.org> (raw)
In-Reply-To: <5a097591-5a6a-44f2-b440-44a2395fa788@huawei.com>
On 7/7/26 11:33, Kefeng Wang wrote:
>
>
> On 7/7/2026 3:04 PM, David Hildenbrand (Arm) wrote:
>> On 7/7/26 03:28, Kefeng Wang wrote:
>>>
>>>
>>>
>>> Yes，device-private entries.
>>>
>>>
>>> I couldn't find a more suitable commit, before a3589e1d5fe3, the
>>> flush_cache_page() only called under anon_exclusive, not a device
>>> private entry, so there is no issue. This is the reason why I chose
>>> this commit.
>>
>> What makes you believe device-private entries wouldn't have PAE set?
>>
>> This likely goes back to initial support for device-private.
>>
>
> We only need to make sure that flush_cache_page(..,pte_pfn(pte)) won't
> be called under no-present pte, I go back and find the
> flush_cache_page function was first introduced to
> migrate_vma_collect_pmd in commit 6c287605fd56, so maybe this commit is
> better for fix tag? what's your option?
That looks about right. For device-private we wouldn't need the ptep_clear_flush
(ptep_get_and_clear would be sufficient), but that's a different optimization.
--
Cheers,
David
next prev parent reply other threads:[~2026-07-07 13:03 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-06 11:19 [PATCH] mm: migrate_device: fix pte_pfn/pte_dirty called on non-present PTE Kefeng Wang
2026-07-06 18:01 ` Andrew Morton
2026-07-07 1:45 ` Zi Yan
2026-07-07 8:00 ` Kefeng Wang
2026-07-06 18:30 ` David Hildenbrand (Arm)
2026-07-07 1:28 ` Kefeng Wang
2026-07-07 7:04 ` David Hildenbrand (Arm)
2026-07-07 9:33 ` Kefeng Wang
2026-07-07 13:03 ` David Hildenbrand (Arm) [this message]
2026-07-07 14:20 ` Kefeng Wang
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