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[79.177.155.147]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48a55dc9f58sm607291535e9.6.2026.04.24.11.36.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 24 Apr 2026 11:36:56 -0700 (PDT) Date: Fri, 24 Apr 2026 14:36:51 -0400 From: "Michael S. Tsirkin" To: "David Hildenbrand (Arm)" Cc: Gregory Price , linux-kernel@vger.kernel.org, Andrew Morton , Vlastimil Babka , Brendan Jackman , Michal Hocko , Suren Baghdasaryan , Jason Wang , Andrea Arcangeli , linux-mm@kvack.org, virtualization@lists.linux.dev, Johannes Weiner , Zi Yan , Lorenzo Stoakes , "Liam R. Howlett" , Mike Rapoport , "Matthew Wilcox (Oracle)" , Muchun Song , Oscar Salvador , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Ying Huang , Alistair Popple , Hugh Dickins , Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH RFC v3 01/19] mm: thread user_addr through page allocator for cache-friendly zeroing Message-ID: <20260424143541-mutt-send-email-mst@kernel.org> References: <20260422171315-mutt-send-email-mst@kernel.org> <20260423074433-mutt-send-email-mst@kernel.org> <88b0765f-7cfc-4e44-83d2-c01a1755c842@kernel.org> <20260423104120-mutt-send-email-mst@kernel.org> <1ab6e58f-d984-4bae-a343-1b0d3c973ad0@kernel.org> <20260423121222-mutt-send-email-mst@kernel.org> <4e12d67b-60e3-4bf5-a229-43c0d2c62cfb@kernel.org> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <4e12d67b-60e3-4bf5-a229-43c0d2c62cfb@kernel.org> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: m3i63ZgvJUkwC1_YBmVwiX7E_CTKrKJZx_VfYKxdSGU_1777055818 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Apr 24, 2026 at 08:33:45PM +0200, David Hildenbrand (Arm) wrote: > On 4/23/26 18:13, Michael S. Tsirkin wrote: > > On Thu, Apr 23, 2026 at 05:54:26PM +0200, David Hildenbrand (Arm) wrote: > >> On 4/23/26 16:46, Michael S. Tsirkin wrote: > >>> > >>> I just dislike it when things are non orthogonal. > >>> People are used to: hugetlb = same perf as THP but more predictable at the cost > >>> of being harder to use and using more resources. > >>> Here, suddenly, we have an optimization but only for THP. > >> > >> Note that we also didn't care about user_alloc_needs_zeroing() with hugetlb so far. > > > > > > You mean, that it stays because of the reserved pool? > > I meant, that if we are running with init_on_free or init_on_alloc, that we end > up double-zeroing right now upstream. So nobody cared to optimize that part so far. on the aliasing arches you mean? that double zeroing? > -- > Cheers, > > David