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AJvYcCVPoAR455nkK/ler00udaGwNnr1bwiAN2rR0/FieDG5RDxP1BuuDZDnNof6ao14Dpas268U604z9Vc3HcdjEpYClcx9kiH7VoFN X-Gm-Message-State: AOJu0YzRcx7++ceUZ56KeFdxw2t38/RePiFI6iN+7HNefwTLD1mc/JV+ VjA9OLfwJBbxrWPEpia8y5FVtZIi9zp1IfLVww+zXV+24XYWblGg4LMj0SqNbtGpmrLlgc1AKAX EBQ== X-Google-Smtp-Source: AGHT+IEk24C6d/QoiBbCyIExMW7OdPZLjaBEK4ZPTTj/IX3O1NfqjnOFuoealUEhXp84xV+hhBOGjvPTh7s= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6902:707:b0:dfa:ba40:6f43 with SMTP id 3f1490d57ef6-dfaba407295mr112473276.2.1717460587664; Mon, 03 Jun 2024 17:23:07 -0700 (PDT) Date: Mon, 3 Jun 2024 17:23:06 -0700 In-Reply-To: Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240529180510.2295118-3-jthoughton@google.com> Message-ID: Subject: Re: [PATCH v4 2/7] mm: multi-gen LRU: Have secondary MMUs participate in aging From: Sean Christopherson To: James Houghton Cc: Yu Zhao , Andrew Morton , Paolo Bonzini , Albert Ou , Ankit Agrawal , Anup Patel , Atish Patra , Axel Rasmussen , Bibo Mao , Catalin Marinas , David Matlack , David Rientjes , Huacai Chen , James Morse , Jonathan Corbet , Marc Zyngier , Michael Ellerman , Nicholas Piggin , Oliver Upton , Palmer Dabbelt , Paul Walmsley , Raghavendra Rao Ananta , Ryan Roberts , Shaoqin Huang , Shuah Khan , Suzuki K Poulose , Tianrui Zhao , Will Deacon , Zenghui Yu , kvm-riscv@lists.infradead.org, kvm@vger.kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, loongarch@lists.linux.dev Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Mon, Jun 03, 2024, James Houghton wrote: > On Mon, Jun 3, 2024 at 4:03=E2=80=AFPM Sean Christopherson wrote: > > But before we do that, I think we need to perform due dilegence (or pro= vide data) > > showing that having KVM take mmu_lock for write in the "fast only" API = provides > > better total behavior. I.e. that the additional accuracy is indeed wor= th the cost. >=20 > That sounds good to me. I'll drop the Kconfig. I'm not really sure > what to do about the self-test, but that's not really all that > important. Enable it only on architectures+setups that are guaranteed to implement the fast-only API? E.g. on x86, it darn well better be active if the TDP MMU i= s enabled. If the test fails because that doesn't hold true, then we _want_ = the failure.