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(p200300cbc7076e00ff02ec7aded5ec1e.dip0.t-ipconnect.de. [2003:cb:c707:6e00:ff02:ec7a:ded5:ec1e]) by smtp.gmail.com with ESMTPSA id r10-20020a05600c458a00b003d35acb0fd7sm2093683wmo.34.2023.01.05.02.47.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 05 Jan 2023 02:47:21 -0800 (PST) Message-ID: <60f06008-dea5-a08e-edec-fc4aec76dfb5@redhat.com> Date: Thu, 5 Jan 2023 11:47:20 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.0 Subject: Re: [PATCH 00/46] Based on latest mm-unstable (85b44c25cd1e). Content-Language: en-US To: James Houghton , Mike Kravetz , Muchun Song , Peter Xu Cc: David Rientjes , Axel Rasmussen , Mina Almasry , Zach O'Keefe , Manish Mishra , Naoya Horiguchi , "Dr . David Alan Gilbert" , "Matthew Wilcox (Oracle)" , Vlastimil Babka , Baolin Wang , Miaohe Lin , Yang Shi , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20230105101844.1893104-1-jthoughton@google.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20230105101844.1893104-1-jthoughton@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05.01.23 11:17, James Houghton wrote: > This series introduces the concept of HugeTLB high-granularity mapping > (HGM). This series teaches HugeTLB how to map HugeTLB pages at > high-granularity, similar to how THPs can be PTE-mapped. > > Support for HGM in this series is for MAP_SHARED VMAs on x86 only. Other > architectures and (some) support for MAP_PRIVATE will come later. Why even care about the complexity of COW-sharable anon pages? TBH, I'd just limit this to MAP_SHARED and call it a day. Sure, we can come up with use cases for everything (snapshotting VMs using fork while also support optimized postcopy), but I think this would need some real justification for the added complexity and possible (likely!) issues. -- Thanks, David / dhildenb