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charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: we7jixrqoknm77tyjsqgk5qxehsaarh1 X-Rspamd-Server: rspam01 X-Rspam-User: X-Spam-Status: No, score=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no autolearn_force=no version=4.0.1 X-Rspamd-Queue-Id: 96EFD80015 X-HE-Tag: 1793719026-534564 X-HE-Meta: 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 tYaTJz0s uI/m/2PqMCdY6V5WH6EjfHnvjW1OAyTo62pgsCnQlGSM+APl2W3R11GWw8FS3BAlO6gCYexBWgZXeRaqTEO9ZMzSICNHVX7qxY0ZByNDW97uxPb4r7+h4im9rqkcg0e1UVPiDNO3p+wghe6B3vzF03r5pkSotQV3D4zIlza9BStxodsC7tvQ7+Yhqw4nyPJBUoo5/z5mQ8vvCdup0Bcn0XT0a9h/zg4yExkLEMBnUXUVmMQwJGj4Aux+YRigDkZyIgxUzWbRSC5bKcOaIHI6G38fR/QXsp4Ke/lHM3xWsGmcuXJ97wLzr4wN+f8gUyj5Puu8ZAbCm5B/tkBW4pdpgbs5+YHLuyehhGp85UOYS9aMMq2fOTUqulEc5p+cQI0aR8BSNYcRyD+libvtDzptWmxKFZB7VQghN4VMKPxE+nIIp8BPAfs/oC3JgbpngXGD8lv7+gy8YbNrq+7/aUc2L2Mq5FcnL3w+ypwpV6GRUsUAalSGZta3XjUjGGtcTVHb4kc0ael5yiX99PQJsLliQZeFJjsY0Yt8Oo++SRxKBXq/AZnZiwylA78aNScru2Ua45rGJEXmqK0wv9kB5wuSXC4xKLwGgZfZ6x8g7cTSTu07oul5fEp8CYlHve16KGi1DHSIYV0SJDDXMJ1v/tZG8wytVoB5Fqv1UlOpZkdeAAX6WW3y8bc27ooEJZ9+wItZMjr+NlraG8qfMuXoyxXFLxOFg6AG9dSY4M1s/OkZsNZEMud7bS9a6SC5J+tChtbctSL/PxZFXonxnR9cL9Ko9Cbn7sbFuqIs84zxMZ9wLOX0xt54= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Tue, Nov 03, 2026, Paolo Bonzini wrote: > On Mon, Nov 2, 2026 at 6:43=E2=80=AFPM Sean Christopherson wrote: > > > If so, we need to make that a thread for RT kernels if you want to ca= ll > > > kzalloc_obj(). > > > > Eww. I can't imagine there's a sane usecase for memory overcommitting = a real-time > > guest. >=20 > While I agree with the feeling, the dummy allocation path should be > mostly dead, because page fault should never (?) enable interrupts > before waiting: >=20 > #PF interrupt gate > exc_page_fault() > kvm_handle_async_pf() > __kvm_handle_async_pf() > irqentry_enter() > kvm_async_pf_task_wait_schedule() > kvm_async_pf_queue_task() <- registers waiter > prepare_to_swait_exclusive() > local_irq_enable() >=20 > The dummy allocation path is only reachable if it's an L1 hypervisor > that is getting an async page fault while L2 is running, because it > enables irq before the call to kvm_async_pf_task_wait_schedule(). I > think we can drop the dummy allocation for good, which would be even > better. +1, I completely forgot what this code is doing (although that implies I ev= er knew in the first place...). > Whether you would still want to disable APF for RT kernels is up to you. Nah, on second thought there are use cases for async #PF other than memory overcommit. Whether or not they coincide with PREEMPT_RT is debatable, but= I don't think it makes sense to go looking for trouble.