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[113.36.239.145]) by smtp.googlemail.com with ESMTPSA id s32sm96035pfw.2.2021.04.25.20.19.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 25 Apr 2021 20:19:12 -0700 (PDT) From: Kenta Ishiguro To: kernellwp@gmail.com Cc: david@redhat.com, jmattson@google.com, joro@8bytes.org, kentaishiguro@sslab.ics.keio.ac.jp, kono@sslab.ics.keio.ac.jp, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, pbonzini@redhat.com, pl@sslab.ics.keio.ac.jp, seanjc@google.com, vkuznets@redhat.com, wanpengli@tencent.com Subject: Re: [RFC PATCH 0/2] Mitigating Excessive Pause-Loop Exiting in VM-Agnostic KVM Date: Mon, 26 Apr 2021 12:18:58 +0900 Message-Id: <20210426031858.12003-1-kentaishiguro@sslab.ics.keio.ac.jp> X-Mailer: git-send-email 2.30.2 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thank you for the reply. My question is about following scenario: 1. running vCPU receives IPI and the vCPU's ipi_received gets true 2. the vCPU responds to the IPI 3. the vCPU exits 4. the vCPU is preempted by KVM 5. the vCPU is boosted, but it has already responded to the IPI 6. the vCPU enters and the vCPU's ipi_received is cleaned In this case, I think the check of vcpu->preempted does not limit the candidate vCPUs.