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[79.176.40.226]) by smtp.gmail.com with ESMTPSA id n42sm10811959qta.31.2019.10.01.12.08.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Oct 2019 12:08:36 -0700 (PDT) Date: Tue, 1 Oct 2019 15:08:24 -0400 From: "Michael S. Tsirkin" To: Alexander Duyck Cc: David Hildenbrand , Alexander Duyck , virtio-dev@lists.oasis-open.org, kvm@vger.kernel.org, dave.hansen@intel.com, linux-kernel@vger.kernel.org, willy@infradead.org, mhocko@kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, mgorman@techsingularity.net, vbabka@suse.cz, osalvador@suse.de, yang.zhang.wz@gmail.com, pagupta@redhat.com, konrad.wilk@oracle.com, nitesh@redhat.com, riel@surriel.com, lcapitulino@redhat.com, wei.w.wang@intel.com, aarcange@redhat.com, pbonzini@redhat.com, dan.j.williams@intel.com Subject: Re: [PATCH v11 0/6] mm / virtio: Provide support for unused page reporting Message-ID: <20191001144331-mutt-send-email-mst@kernel.org> References: <20191001152441.27008.99285.stgit@localhost.localdomain> <7233498c-2f64-d661-4981-707b59c78fd5@redhat.com> <1ea1a4e11617291062db81f65745b9c95fd0bb30.camel@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1ea1a4e11617291062db81f65745b9c95fd0bb30.camel@linux.intel.com> 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: On Tue, Oct 01, 2019 at 09:21:46AM -0700, Alexander Duyck wrote: > I thought what Michal was asking for was what was the benefit of using the > boundary pointer. I added a bit up above and to the description for patch > 3 as on a 32G VM it adds up to about a 18% difference without factoring in > the page faulting and zeroing logic that occurs when we actually do the > madvise. Something maybe worth adding to the log: one disadvantage of the tight integration with the mm core is that only a single reporting device is supported. It's not obvious that more than one is useful though. -- MST