linux-kernel - Re: [RFC PATCH] mm: hold PTL from the first PTE while reclaiming a large folio

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Message-ID: <87v86186dc.fsf@yhuang6-desk2.ccr.corp.intel.com>
Date: Tue, 05 Mar 2024 15:50:23 +0800
From: "Huang, Ying" <ying.huang@...el.com>
To: David Hildenbrand <david@...hat.com>
Cc: Ryan Roberts <ryan.roberts@....com>,  Barry Song <21cnbao@...il.com>,
  akpm@...ux-foundation.org,  linux-mm@...ck.org,  chrisl@...nel.org,
  yuzhao@...gle.com,  hanchuanhua@...o.com,  linux-kernel@...r.kernel.org,
  willy@...radead.org,  xiang@...nel.org,  mhocko@...e.com,
  shy828301@...il.com,  wangkefeng.wang@...wei.com,  Barry Song
 <v-songbaohua@...o.com>,  Hugh Dickins <hughd@...gle.com>
Subject: Re: [RFC PATCH] mm: hold PTL from the first PTE while reclaiming a
 large folio

David Hildenbrand <david@...hat.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