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b=V2JzVDB+N5ImbK6LsGROmwY8AFEtbPDnok+ulyssyRJWuG4HIdxR8GX9dBDXCxm7G PVFkml1jkhQsqoL+W2AwkfVjXHNAlHG68fNELXMo72eiqz30B7YO5OnB9SqLhHC7EW SNaaLXrkTMhbaLT7IBITbeLIcGQ12lkmy8VufCOvczK/L+9k/gH0/vruMKfCebvYvO iSFSgHngJlEbyV/N0dVwwMbTrFN05CS0xCmvpzEiyc9B8GQWKg4owEvLKUUDebDk7u 5KyIwcV4d/ERxRU4C3gaH+kSj8CY/jXKc1P/gnVw9Rj+W433rL1R63HRTQ2V9nXexh xJYghDYgCwp/g== Message-ID: <16ca5667-ae65-4bf0-8efb-e51bf7d70c87@kernel.org> Date: Mon, 18 May 2026 11:59:39 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC] __GFP_UNMAPPED and __GFP_PRIVATE follow up To: Brendan Jackman , Gregory Price , linux-mm@kvack.org Cc: kernel-team@meta.com, vishal.l.verma@intel.com, ira.weiny@intel.com, dan.j.williams@intel.com, longman@redhat.com, akpm@linux-foundation.org, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, osalvador@suse.de, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, ying.huang@linux.alibaba.com, apopple@nvidia.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, yury.norov@gmail.com, linux@rasmusvillemoes.dk, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, tj@kernel.org, hannes@cmpxchg.org, mkoutny@suse.com, sj@kernel.org, baolin.wang@linux.alibaba.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, muchun.song@linux.dev, xu.xin16@zte.com.cn, chengming.zhou@linux.dev, jannh@google.com, linmiaohe@huawei.com, nao.horiguchi@gmail.com, pfalcato@suse.de, rientjes@google.com, shakeel.butt@linux.dev, riel@surriel.com, harry.yoo@oracle.com, cl@gentwo.org, roman.gushchin@linux.dev, chrisl@kernel.org, kasong@tencent.com, shikemeng@huaweicloud.com, nphamcs@gmail.com, bhe@redhat.com, zhengqi.arch@bytedance.com, terry.bowman@amd.com, owner-linux-mm@kvack.org References: From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: nswdjq6ddwdt7iumaf8omg5ez3zjxeom X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: C87D318000C X-Rspam-User: X-HE-Tag: 1779098402-994238 X-HE-Meta: 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 TJsg1oGt YwL5kNZBKim1eYUmtQaOZmRPpHCKEwRQnVFVWMOmXvYt3FGjVfMZSXGdywP+F1LqjGUBif+vQxRNbnPVxMGEb2jGRraIMhf7dOUV2kmc8ZH1SJgDB3XrSVM9P88FyDoyGtQOH/0Nh+RrE/Ibsgp32Ctxt10ETTTGonP9WSw6+ONhSwZG/oVKM9XKUV4nGVQLf4w5vH2ZUL5fVrQJOF4pYuY18/3XnqQSMHS7+3MRNcbMLxunFCMtCEAwQUV5Gdtl9fFbTseWBnIcSmt7B8zi/s0Hi5fQzsA4kPyYdgSQUugq1OvgaWHdHjWd/WX6I2WkyldImLT3mdatmGshrCE20jqEAqx3ao5EBkhCQsJ7o0/IDR7lrdShZD7+TXw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 5/15/26 11:43, Brendan Jackman wrote: > On Thu May 14, 2026 at 5:42 PM UTC, Gregory Price wrote: > ... >> Maybe we could modify alloc_flags to be a struct, and export that >> without being tied to down to a 32/64-bit flag field - and mark certain >> sets of alloc flags verboten (internally controlled / controlled by GFP >> flags, and will either be ignored or cause a BUG()). >> >> Then we could get something like: >> >> struct alloc_flags { >> /* >> * internal only: will be ignored, cleared, or cause BUG() if used, >> * or should be applied via the appropriate __GFP flag. >> */ >> uint64_t wmark_min : 1; >> uint64_t wmark_low : 1; >> uint64_t wmark_high : 1; >> ... etc ... >> /* >> * external context flags >> * allows explicit access to certain resources >> */ >> uint64_t cma : 1; /* allows access to CMA regions */ >> uint64_t unmapped : 1; /* return pages in unmapped state */ >> uint64_t managed_node : 1; /* allows access to managed node */ >> ... etc ... >> }; Wouldn't it be cleaner to really only export what we want external users to consume? IOW, a split between internal and external flags. We do that for gup-flags, but I wouldn't suggest that models as is, just the overall idea. There are other ways to achieve it I guess. -- Cheers, David