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[70.31.26.132]) by smtp.gmail.com with ESMTPSA id dt17-20020a05620a479100b006fbf88667bcsm369321qkb.77.2022.12.22.06.30.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Dec 2022 06:30:28 -0800 (PST) Date: Thu, 22 Dec 2022 09:30:25 -0500 From: Peter Xu To: James Houghton Cc: Mike Kravetz , Muchun Song , David Hildenbrand , 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 Subject: Re: [RFC PATCH v2 33/47] userfaultfd: add UFFD_FEATURE_MINOR_HUGETLBFS_HGM Message-ID: References: MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Rspam-User: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: EEF9A4001D X-Stat-Signature: swoe8mhf377f3ud66fas7bujfkez6osg X-HE-Tag: 1671719432-173908 X-HE-Meta: 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 cMovM0KS kW7i/vP52BeOpTquOnTPIwy6v/89TFaFWh0PuUXLnbWlZySHLxAq0VUhAHmYfMgOi4tHjHLf2E82U9mk/62NdYKLVkxUy3rJf+9D3I+J3QXnzYy/qbfvuGB1ZijuExN8J48DksiR1dghJnCeTKPWx9IVJ/fxdXfTDgx30 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 Wed, Dec 21, 2022 at 08:24:45PM -0500, James Houghton wrote: > Not sure what the best name for this flag is either. MADV_ENABLE_HGM > sounds ok. MADV_HUGETLB_HGM or MADV_HUGETLB_SMALL_PAGES could work > too. No need to figure it out now. One more option to consider is MADV_SPLIT (hopefully to be more generic). We already decided to reuse thp MADV_COLLAPSE, we can also introduce MADV_SPLIT and leave thp for later if it can be anything helpful (I remember we used to discuss this for thp split). For hugetlb one SPLIT should enable hgm advise bit on the vma forever. Thanks, -- Peter Xu