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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , , "H. Peter Anvin" , Brendan Jackman , Johannes Weiner , Zi Yan , Oscar Salvador , Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , , References: <20260915-hwpoison-kho-v5-0-3bc7a57bd503@debian.org> From: Miaohe Lin Message-ID: <16baab50-692c-308b-d60d-1b0a328df1e3@huawei.com> Date: Tue, 22 Sep 2026 17:29:14 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.173.124.160] X-ClientProxiedBy: kwepems200001.china.huawei.com (7.221.188.67) To whupemk100004.china.huawei.com (7.152.185.74) X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 045D1C0002 X-Rspam-User: X-Stat-Signature: uc35sdj57yherjxeje47okbg4kpicspx X-HE-Tag: 1790069364-356119 X-HE-Meta: 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 m4rFCqah +RaNnEJTxi/Un4js63B/U5+oR0V3jevkQNXKlWkg5IHNgpSSuxXU2gOwHdk8z+xF8enAdSTi17kL0jdQKKZLzwBMntxgKTWB0cqGonkn0wXjLHzhyr20tE8he4thu4kKfTsL490KxfJdjNYF9St71qAGHOeOtt4JftrncaPm5LUdMvLJWZjacX80ER8A2lp7+blqyPi9EIkRnURR1uZk7zKbkUfhQEXzBLxQmGh4E90veQJE3K6tiYJw4J+7zcx6m+Y1ga3LjwESknHybtImdcfqWikLGe/OONPvg8vmwcfYCCabx4Otv2SVz801liQs5BloRnTeHKRFlBLXRYMkZ7hnRXto0x4yQ6VV1 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2026/9/22 17:14, Breno Leitao wrote: > Hello Miaohe, > > On Tue, Sep 22, 2026 at 02:27:59PM +0800, Miaohe Lin wrote: >>> A bit is never cleared, which is a known limitation: it stands for a >>> whole unit, so an unpoison of one frame cannot tell whether the unit as a >>> whole is good again. >> >> Thanks for your patches. I have a question about unpoison: If a bit is never >> cleared, after we do some memory-failure+unpoison tests, kexec will lose the >> tested memory without reboot? > > Correct, A bit stands for a 2M unit, so every tested page that falls in > a distinct unit costs 2M in each kernel after the kexec. > > Worth being precise about the state today: the unpoison itself works. > The frame goes back to the allocator and num_poisoned_pages drops. Only > the bit stays, so the next kernel poisons the frame again. Test loop > in, memory out, and nothing gives it back. > > Important to say that nothing block us from unpoison the bitmap, and in > fact my initial patchset had it. I also _think_ we should unpoison the > bitmap once we unpoison the page. > > I have just kept it out of this patch in order to simplify the patchset and > get the basis correct, and then evolve on top of it. > Makes sense to me. Thanks for your work. > That said, If you think this is a must have in first patchset, I am more > than happy to do it now, but just keep it in mind that it will grow the > patchset by about 2 extra functions. > > Thanks the review, > --breno > . >