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AJvYcCXZJ9irBOZHmWgFPGtTp9ZZ5heLMW1itI8XexojmreiSuQYaz/edvCOL+t3QN4pV8Wbckh9YrKWJg==@kvack.org X-Gm-Message-State: AOJu0YxpHdzf/XFVL7o1PNnuQL5QkGibfAYPPqLOGT9KRCl9wmYq487Z yzQGib9uVQb0TxFWD3HwT5E4rrPuhjs1nCj+JgC/KBZRP+VFriLnIhiZPd/uYRI3Mvx/+PDeEql fscRnl8+Bmu30wB8kJA0rJLh+1HP4PLzTGSRceZPU X-Gm-Gg: ASbGncsHAoj3cSMDG5YdgDMrVDW7j0r74v6bUN9V3Ye86UJhYXaHCWOrpKBe4T4XvWF z5oFh/dA+7fUR1FBWm8RyR3tfuRV8z9gXsf0p2qONqmTfWGKYi5J4/fWgOrPi9RKjhhzDaM0d25 gsTi8Rsx2JZZ0DnQv3EujOmpiTSHuzYShXo27p+P72n0cfv7VbI1kM3X3htJ229AmxaDywIIXMq KbJYIVwXRjEQE4gVxejg9C8H9T1YnkgOH+/gdWCWy2RLA6cPyOuuvmW2w== X-Google-Smtp-Source: AGHT+IGoVtKn/z+fvBHETKBwCTIhHjfyaWPkAklb+f6MmLruI8Ybm05I9etHLrGBfigctLEhHMHLShZjSxTcGUhWdbc= X-Received: by 2002:a05:600c:4849:b0:45f:2e6d:c9ee with SMTP id 5b1f17b1804b1-46e56713c8emr799655e9.6.1759158958285; Mon, 29 Sep 2025 08:15:58 -0700 (PDT) MIME-Version: 1.0 References: <20250928032842.1399147-1-qiuxu.zhuo@intel.com> <5f117b73-8d7b-b233-a0a8-2a29ea6312a8@huawei.com> In-Reply-To: From: Jiaqi Yan Date: Mon, 29 Sep 2025 08:15:46 -0700 X-Gm-Features: AS18NWBdlALjklZrPik0xP6HICNNusJc_VQT87GL7dSv5ULvD7SM592G5TPsAWM Message-ID: Subject: Re: [PATCH 1/1] mm: prevent poison consumption when splitting THP To: "Zhuo, Qiuxu" , Miaohe Lin , "david@redhat.com" Cc: "akpm@linux-foundation.org" , "lorenzo.stoakes@oracle.com" , "Luck, Tony" , "ziy@nvidia.com" , "baolin.wang@linux.alibaba.com" , "Liam.Howlett@oracle.com" , "npache@redhat.com" , "ryan.roberts@arm.com" , "dev.jain@arm.com" , "baohua@kernel.org" , "nao.horiguchi@gmail.com" , "Chen, Farrah" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Andrew Zaborowski Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 18F0E14000A X-Stat-Signature: czjt5csm3doy3e664f89ts46iuo9ck3i X-Rspam-User: X-HE-Tag: 1759158959-353325 X-HE-Meta: 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 no6XUWE+ +BUSBk3dFgRucM+b/b0FQzIgz8Q29xAE8YWdbQp/6qK6NmPMKL1ReKcpP0g== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Sep 29, 2025 at 6:57=E2=80=AFAM Zhuo, Qiuxu = wrote: > > Hi Miaohe, > > > From: Miaohe Lin > > [...] > > >> First Machine Check occurs // [1] > > >> memory_failure() // [2] > > >> try_to_split_thp_page() > > >> split_huge_page() > > >> split_huge_page_to_list_to_order() > > >> __folio_split() // [3] > > >> remap_page() > > >> remove_migration_ptes() > > >> remove_migration_pte() > > >> try_to_map_unused_to_zeropage() > > > > > > Just an observation: Unfortunately THP only has PageHasHWPoisoned and > > > don't know the exact HWPoisoned page. Otherwise, we may still use > > > zeropage for these not HWPoisoned. > > > > IIUC, the raw error page will have HWPoisoned flag set while the THP ha= s > > PageHasHWPoisoned set. So I think we could use zeropage for healthy sub= - > > pages. Oh, sorry, somehow I forgot this so I thought there is no better place to do the HWPoison check than in __folio_split. Yeah, since we know the exact raw error page, checking in try_to_map_unused_to_zeropage like David suggested is much better! > > Good point. > > David's suggested diff in another e-mail checked the raw error page inste= ad of > entire folio. And I tested that diff and it worked well. > > -Qiuxu