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charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: kcjy14gzip5ru4zqw3q717dh37ueutxe X-Rspam-User: X-Rspamd-Queue-Id: 4483B18001F X-Rspamd-Server: rspam02 X-HE-Tag: 1724107640-663705 X-HE-Meta: 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 lE8DAmQ3 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 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, Aug 19, 2024, Oliver Upton wrote: > On Fri, Aug 16, 2024 at 07:03:27PM -0600, Yu Zhao wrote: > > On Fri, Aug 16, 2024 at 6:46=E2=80=AFPM Sean Christopherson wrote: >=20 > [...] >=20 > > > Were you expecting vCPU runtime to improve (more)? If so, lack of mo= vement could > > > be due to KVM arm64 taking mmap_lock for read when handling faults: > > > > > > https://lore.kernel.org/all/Zr0ZbPQHVNzmvwa6@google.com > >=20 > > For the above test, I don't think it's mmap_lock >=20 > Yeah, I don't think this is related to the mmap_lock. >=20 > James is likely using hardware that has FEAT_HAFDBS, so vCPUs won't > fault for an Access flag update. Huh, didn't know that was a thing on ARM. Ooh, that lends even more creden= ce to my assertion that marking folios accessed in handle_access_fault() can go a= way[*]. I assume hardware-assisted updates means this code in handle_access_fault()= will no longer be hit, as KVM simply won't ever get access faults? If so, I'll = add that info to the changelog. if (kvm_pte_valid(pte)) kvm_set_pfn_accessed(kvm_pte_to_pfn(pte)); [*] https://lore.kernel.org/all/20240726235234.228822-83-seanjc@google.com > Even if he's on a machine w/o it, Access flag faults are handled outside = the > mmap_lock. Oh, right, they go down handle_access_fault(), not user_mem_abort(). Reviewing late Friday afternoon, never a good idea ;-)