From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Zi Yan <ziy@nvidia.com>, Hui Su <sh_def@163.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: 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>,
Balbir Singh <balbirs@nvidia.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/migrate_device: fix cache flush when replacing huge zero PMD
Date: Mon, 17 Aug 2026 19:47:51 +0200 [thread overview]
Message-ID: <4148c151-5ef7-4e5e-986e-b05e600045db@kernel.org> (raw)
In-Reply-To: <DKRD8RERQHHC.1CVF14YIY4BSA@nvidia.com>
On 8/17/26 18:39, Zi Yan wrote:
> On Mon Aug 17, 2026 at 2:08 AM EDT, Hui Su wrote:
>> migrate_vma_insert_huge_pmd_page() calls flush_cache_page() before
>> replacing an existing huge zero PMD. However, the third argument to
>> flush_cache_page() is a PFN, while addr + HPAGE_PMD_SIZE is an end
>> virtual address.
>>
>> More importantly, the mapping being invalidated is PMD-sized rather
>> than PAGE_SIZE-sized. Flush the whole PMD range with
>> flush_cache_range(), matching other huge PMD invalidation paths.
>>
>> Fixes: a30b48bf1b24 ("mm/migrate_device: implement THP migration of zone device pages")
>> Signed-off-by: Hui Su <sh_def@163.com>
>> ---
>> mm/migrate_device.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>
> Thank you for fixing it.
>
> Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
I do wonder whether there should be a PMD helper.
--
Cheers,
David
prev parent reply other threads:[~2026-08-17 17:47 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-17 6:08 [PATCH] mm/migrate_device: fix cache flush when replacing huge zero PMD Hui Su
2026-08-17 7:35 ` Balbir Singh
2026-08-17 16:06 ` Andrew Morton
2026-08-17 16:36 ` Hui Su
2026-08-17 21:34 ` Andrew Morton
2026-08-17 22:06 ` Balbir Singh
2026-08-17 22:12 ` Andrew Morton
2026-08-17 16:39 ` Zi Yan
2026-08-17 17:47 ` David Hildenbrand (Arm) [this message]
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