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b=fZRK+pzhRc25aW/wW0SKbu275nX+soOunXyesHz5tvU5vabsaNBeX6xxGODZJ107b qxr6bX6XbTsQSvbiAkNRlYarsu+qCsfbihRwrcaDV0r3fciz6bayHa0eGO8mC9JdSC ERElfHyth50mNYfJi44HGvoAJpIv119eMebycDMLpVZDdmOOhWfG8hq7Dtl1d8676J 2/kwux5Ywtnjzy1h1PODGDkQUIxdd8CGx6j3bzNCKnHT9MjlmhLW4W2Cp6YthzFF+7 0fHFnG5KKNGc1Lqp6bWWK21JmNqagFj8A8KULuq9/TDNZ/Wl7vWyb6xy7N5eQzm2je 5CR1v5k+e93dA== Message-ID: Date: Wed, 26 Aug 2026 10:08:58 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/3] mm: khugepaged: fix swap entry value to folio_pfn() To: "Lorenzo Stoakes (ARM)" Cc: Vernon Yang , akpm@linux-foundation.org, nico.pache@linux.dev, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, usama.arif@linux.dev, zokeefe@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org, Vernon Yang References: <20260824092935.73892-1-vernon2gm@gmail.com> <20260824092935.73892-2-vernon2gm@gmail.com> <6a9c2369-5589-4f2a-bcfe-c6e3b46a1ccd@gmail.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: 33c1y41benwwtmuwph1hg4sjettde64i X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 914F140004 X-Rspam-User: X-HE-Tag: 1787731744-560257 X-HE-Meta: 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 H9h5VN4O r9dIpOIIF1hRzn0RY62QoDm6tli156uONp6D/0Vz25MZ+3RPtO/Fpu5etJ87azRr/7cxfAvLgXtejUneI4C3ei/5/UGfetKa+v9iCTb0AFudSaqA4DaPMLs9JBq50NSAVsY/pTXR1HpBKUxn2tKn+D3x8c8IwS88WcEweVct2TNFIMwIut+sC+RkuZjdOKx3NTw4Up2SBSyd+TDTovs/1za4TyK/HWZUO4+BgWEH/9ev+mTUjuzNH7fehvqCrRumwGHWFwQJM2wSIZqkOEFQIPz24rO4Xo5H5K00hKQtcNYYOyJvAbz0MkmH2bw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 8/26/26 10:07, Lorenzo Stoakes (ARM) wrote: > On Wed, Aug 26, 2026 at 09:57:05AM +0200, David Hildenbrand (Arm) wrote: >> On 8/26/26 04:44, Vernon Yang wrote: >>> >>> When the `xas_for_each()` iteration to terminate and the folio operation >>> preceding is normal, but pfn will be incorrect. >> >> The PFN is only relevant when a folio participated in the failure. Maybe the >> following would be cleanest? >> >> diff --git a/mm/khugepaged.c b/mm/khugepaged.c >> index 75639298efc27..371ee0b16d10c 100644 >> --- a/mm/khugepaged.c >> +++ b/mm/khugepaged.c >> @@ -2683,6 +2683,7 @@ static enum scan_result collapse_scan_file(struct >> mm_struct *mm, >> int present, swap; >> int node = NUMA_NO_NODE; >> enum scan_result result = SCAN_SUCCEED; >> + unsigned long problematic_pfn = -1; > > I find this name... problematic :) Elaborate. -- Cheers, David