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AJvYcCXVs0EozIrAecm/SZ15E90uLzOROVcz/Zq4xRXDmyykvZhnLVAY+VZnTlJ+vSNzJJTbVmG42j4JVQ==@kvack.org X-Gm-Message-State: AOJu0YzqNDZJE97CPoae7gdOv7lAySlMneO11LxxDJ8lttLlcCg9MWUQ Zj+CaKluvQRfwIUmMlHtRthibzYQ643Pr4lcmGK5+8CLHfIW3dLT1fEWpWsc6WAy75hcAT9uWsN Vbf/BiNzf+cO4/uF3oZIY6Ev5WwMg5k2GASgHFTAXogSeTcLGXFpi X-Gm-Gg: ASbGncuieK2qywhTSwJrwHMRw2U/lYdSrKPLmymFjjt+BD1VsingOG/xH3hjhlpICWj HYQPCrRTPipn0hw+jOL7isG1NuwGCazS4sXSP7DlSD5Ibgjsh0KwWDpZFhds+ X-Google-Smtp-Source: AGHT+IFf23UjgxBvi6cbEN9G2RNJ3qaMdQjKGgP7AOyIsD9X639KzBJzQi4ofLaLAMbds9mhDylS1ilHFOl/pRDY6Ls= X-Received: by 2002:a05:6512:ad6:b0:52c:dd94:73f3 with SMTP id 2adb3069b0e04-53c7bb7cbcfmr602427e87.3.1730473724942; Fri, 01 Nov 2024 08:08:44 -0700 (PDT) MIME-Version: 1.0 References: <9242f7cc-6b9d-b807-9079-db0ca81f3c6d@google.com> In-Reply-To: From: Jiaqi Yan Date: Fri, 1 Nov 2024 08:08:30 -0700 Message-ID: Subject: Re: [Invitation] Linux MM Alignment Session on Memory Error Detector on Wednesday To: David Rientjes , Dave Hansen , David Hildenbrand , Jane Chu , Tony Luck , Miaohe Lin , Peter Xu , Jason Gunthorpe , Duen-wen Hsiao Cc: Andrew Morton , Hugh Dickins , Johannes Weiner , John Hubbard , Matthew Wilcox , Mel Gorman , Michal Hocko , Mike Rapoport , Pasha Tatashin , "Rao, Bharata Bhasker" , Rik van Riel , Roman Gushchin , Shakeel Butt , "Shutemov, Kirill" , Tejun Heo , Vlastimil Babka , Yang Shi , Zi Yan , linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 645A3140023 X-Stat-Signature: yhq69xk8u3nt3eafk68tctqrydeqo9xe X-Rspam-User: X-Rspamd-Server: rspam05 X-HE-Tag: 1730473708-267695 X-HE-Meta: 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 NvqS8k3W cTk0Stg/TuTAri2+O7KPALdbNc1Tyw/g5qChMiHLVIIhz1i3fVWPyKhZ/h49J6JyN03DhTauJqu8TbNAR4woTaTsGjgAtzxT8YPwENaYhiomg55b0fFE7u1ORlSW00DboMPuYqiXJ5rWNo5DpVqPs2nJ5cxSm++AoOS0LijQUs4oMykKo80UMq9GRW2qqyi1Oc0rW66lQOHFedt4nqOqsqGQoU88ZMHP72qbV7IM5N81WdcUY/k9igVP1poAlLoijFpGvEuF052NVmQyZiZlDrRyTPSRa5Kvcitu4cfH4WPRi4CAJZKWwWu6KoTvTCNyVWZEZQ/26LwnoEB+wrYL8Jk8n5/ArHu/r7Qe65UZY8EVE3QGwzbg0FEg/XWRSQtkCvGk5zba8KJZyiY7eVHxkFPe+rWYalkTtIpQmszRDobbQSeIciwq2/imnDw== 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: Thanks everyone for the discussion Wednesday! To follow up with the questions I wasn't able to catch during the meeting, and my next steps: Dave Hansen: If one motivation for this is "guest performance", then it would be great to have some data to back that up, even if it is worst-case data. Jiaqi: Definitely, I will set up some memory cycler workload and try measure the delta between with and without S2 shattering due to memory errors. Peter Xu: we have folio_set_has_hwpoisoned() for folios, right? (besdies PG_hwpoison) David Hildenbrand: Yes, for !hugetlb IIRC. It prevents us from having tos can all page flags. Jane Chu: right, to mark poisoned non-head subpages Peter Xu: i thought that's ok, so when free the folio it knows something within is poisoned, so it needs a split / degrade / etc. as long as spread to hugetlb pages Jiaqi: Ack, HasHWPoison is a good tool for kernel to project subsequent memory poison consumption (i.e. MCE again and again). I think it would be better for me to separate the MFR policy from subsequence memory poison protection: no matter what policy is set by userspace and no matter how the policy is implemented, kernel will eventually take actions to split, dissolve, and isolate the raw poisoned page (let's stick with page size for now, instead of cacheline size). With this requirement, I think the global policy design is out. I do want to spend some time to think more about attaching the MFR policy with memfd, the proposal from Jason. Memfd already works with HugeTLBFS and THP, and IIRC will work with guestfs. Will sent out a RFC if I can put out a design (and code). Thanks, Jiaqi On Mon, Oct 28, 2024 at 4:50=E2=80=AFPM Jiaqi Yan wro= te: > > Thanks David for sending out the invite! > > On Mon, Oct 28, 2024 at 2:25=E2=80=AFPM David Rientjes wrote: > > > > Hi everybody, > > > > We host a biweekly series, the Linux MM Alignment Session, on Wednesday= s. > > We'd like to invite MM developers to attend and will announce the topic > > for the next instance on the Monday prior to the next meeting. > > > > Our next Linux MM Alignment Session is scheduled for Wednesday. The > > details: > > > > Wednesday, October 30 * 9:00 - 10:00am PDT (GMT-7) > > https://meet.google.com/csb-wcds-xya > > backup: (US) +1 347-682-5874 PIN: 356 962 072# > > international: https://tel.meet/csb-wcds-xya?pin=3D1301132214803 > > > > This week's topic will be supporting Memory Error Detector APIs led by > > Just a minor correction: the topic is how to make userspace control > memory failure recovery. > > > Jiaqi Yan. See > > https://lore.kernel.org/linux-mm/20240924043924.3562257-2-jiaqiyan@goog= le.com/T/ > > I have prepared some draft slides here: > https://docs.google.com/presentation/d/1tWqcuAqeCLhfd47uXXLdu2SzolKu7WYvM= 03vEkbhobc > > > > > There is lots of interest in these topics, so feel free to forward this > > along to anybody else who may be interested! > > > > Also: if anybody has ideas for future topics, please let me know and I'= ll > > try to organize them. We'd love to have volunteers to lead future topi= cs > > as well as requests for MM topics to be presented. > > > > Looking forward to seeing all of you on Wednesday! > >