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From: "Huang, Ying" <ying.huang@intel.com>
To: David Hildenbrand <david@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>,  Barry Song <21cnbao@gmail.com>,
  akpm@linux-foundation.org,  linux-mm@kvack.org,  chrisl@kernel.org,
  yuzhao@google.com,  hanchuanhua@oppo.com,  linux-kernel@vger.kernel.org,
  willy@infradead.org,  xiang@kernel.org,  mhocko@suse.com,
  shy828301@gmail.com,  wangkefeng.wang@huawei.com,  Barry Song
 <v-songbaohua@oppo.com>,  Hugh Dickins <hughd@google.com>
Subject: Re: [RFC PATCH] mm: hold PTL from the first PTE while reclaiming a
 large folio
In-Reply-To: <37f1e6da-412b-4bb4-88b7-4c49f21f5fe9@redhat.com> (David
	Hildenbrand's message of "Mon, 4 Mar 2024 13:41:38 +0100")
References: <20240304103757.235352-1-21cnbao@gmail.com>
	<706b7129-85f6-4470-9fd9-f955a8e6bd7c@arm.com>
	<37f1e6da-412b-4bb4-88b7-4c49f21f5fe9@redhat.com>
Date: Tue, 05 Mar 2024 15:50:23 +0800
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David Hildenbrand <david@redhat.com> writes:
>
> As we are seeing more such problems with lockless PT walks, maybe we
> really want some other special value (nonswap entry?) to indicate that
> a PTE this is currently ondergoing protection changes. So we'd avoid
> the pte_none() temporarily, if possible.

This sounds like a good idea.  This can solve other issue caused by
temporarily pte_none() issue too, like the following,

https://lore.kernel.org/linux-mm/20240229060907.836589-1-zhangpeng362@huawei.com/

--
Best Regards,
Huang, Ying