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AJvYcCVCxq0/jt5TaUqwvZoElGiGVDNmUpBzWYkowvdEAoAASl9kssqbhLIpZzNFsS8+QbAAMwm96q9bow==@kvack.org X-Gm-Message-State: AOJu0Ywoe4KLLmAZrYjWMPc2OZScP4lxSBTs+U0xhfZwCsG/ClGOIeRB u1QH7s4qSxoNWEth44Vrq2M6nefIaDuCjK1BkouU4MigKhAfSomAyht2niGwhlNolneA5aCPsH1 Qputx/mP7AwK+qirUV5PohPvj5M7bl3P0N5Ro53bp6gVvkMnViQ== X-Gm-Gg: ASbGncuzqG+IRwUCcjMwmPJJkXgtLph9QQ1btWfXjI5IbraAluaOz4YDjonnM2lNvfb bu1aK216u+vXNFir0ns0X4ndhxwph0SVJj/JRX3O33moZX2LAXQl8sVKFyi+bqwwK7MQaNA== X-Google-Smtp-Source: AGHT+IHhKBd7dNubRiwyGndNcsiaFwetl/eM0V1Kf3Op4HcqGv3uLGgg1Y37PP3XKrjCj0ShSAdSCry7Oyv/CyMjvS4= X-Received: by 2002:a05:622a:181f:b0:46c:78e4:a9cc with SMTP id d75a77b69052e-46feb0d5af2mr179561cf.25.1738265980886; Thu, 30 Jan 2025 11:39:40 -0800 (PST) MIME-Version: 1.0 References: <882b566c-34d6-4e68-9447-6c74a0693f18@redhat.com> In-Reply-To: <882b566c-34d6-4e68-9447-6c74a0693f18@redhat.com> From: Frank van der Linden Date: Thu, 30 Jan 2025 11:39:29 -0800 X-Gm-Features: AWEUYZlTkvH928Ha5DSmcYuBqPngMiE6zModhb0fpz3OEznPldEh7lpaOmc5cEk Message-ID: Subject: Re: [LSF/MM/BPF TOPIC] Migrating the un-migratable To: David Hildenbrand Cc: "lsf-pc@lists.linux-foundation.org" , linux-fsdevel@vger.kernel.org, "linux-mm@kvack.org" , Jeff Layton , Zi Yan , Shakeel Butt , Joanne Koong , Miklos Szeredi Content-Type: text/plain; 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Something similar can happen ->readahead() > where user space is in charge of supplying page content. Networking > filesystems in general seem to be prone to this as well. > > As another example, failing to split large folios can prevent migration > if memory is fragmented. XFS (IOMAP in general) refuses to split folios > that are dirty [3]. Splitting of folios and page migration have a lot in > common. > > This session is to collect cases that are known to be problematic, and > to start discussing possible approaches to make some of these > un-migratable allocations migratable, or alternative strategies to deal > with this. > > > [1] https://lkml.kernel.org/r/20250129115411.2077152-1-david@redhat.com > [2] > https://lkml.kernel.org/r/CAJnrk1ZCgff6ZWmqKzBXFq5uAEbms46OexA1axWS5v-PCZ= FqJg@mail.gmail.com > [3] > https://lkml.kernel.org/r/4febc035-a4ff-4afe-a9a0-d127826852a9@redhat.com > > -- > Cheers, > > David / dhildenb > > We have run in to the same issues (especially the writeback one), so a definite +1 on this topic from me. - Frank