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Howlett" , Suren Baghdasaryan , Qi Zheng , linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: References: <20260825084608.47437-1-songmuchun@bytedance.com> <20260825084608.47437-5-songmuchun@bytedance.com> To: "David Hildenbrand (Arm)" X-Mailer: Apple Mail (2.3864.700.51.1.1) X-Stat-Signature: ai3i1bexmecz8owbama493fzszqhzoxs X-Rspam-User: X-Rspamd-Queue-Id: 1D8821C0003 X-Rspamd-Server: rspam03 X-HE-Tag: 1788958161-713823 X-HE-Meta: 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 fgQ/Uqb5 ZxBnl57Jk5rxp4rNOVC7qHj8f930XUvagdrs8Zg0TplOvEzm0h+QMeB45PhtjhyiR0LQLe4xnSx/3zvmg8ru04eHTtMVVy0IJaDo5+uCI+iXt7v554Lg9GZ+HMDB5U/fN3MdpYzdcpeREGrhnhil/6hunQvSTX09i8FURbhLh/goQ22GVGYja87EpYiL57BqnHQBO54XiCKyAW0dOdorHMeP2d5tuxjT4tWbOItQfvD68rySEnYOx+wqRb1sLsFu6S0GOib7mHThKmhWC/qt04uPdEmRVi512EgYQ5c7Jw9qcLFsaAc2shHut0ol8gZ0aPZNRe8Aq2deCf0qG6GMFZutC77TwFcmFF5OnLuW6PbBjNrg= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: > On Sep 9, 2026, at 17:39, David Hildenbrand (Arm) = wrote: >=20 > On 8/25/26 10:45, Muchun Song wrote: >> The shared tail vmemmap page allocated in vmemmap_get_tail() used to = be >> left uninitialized, because memmap_init_range() would later overwrite >> it. That forced users such as HugeTLB to defer the initialization to >> their own setup paths. >>=20 >> Now that memmap_init_range() skips shared tail vmemmap pages, = initialize >> them immediately in vmemmap_get_tail() with init_compound_tail() >> instead. >>=20 >> This moves the initialization to the point where the shared tail page = is >=20 > You are not really moving the initialization? I see a new = initialization being > added but none getting removed. >=20 > Wouldn't hugetlb_bootmem_struct_page_init() have to be updated as well = (as the > comment you are changing indicates) or what am I missing? Strictly speaking, this patch adds initialization rather than removing = it. I used "moves" from a logical perspective: the initialization = responsibility now shifts to the allocation point (vmemmap_get_tail()), making the = HugeTLB side redundant. But since this is a preparatory patch (the section order = field isn't set yet, so the skip logic introduced in patch 3 doesn't take = effect =E2=80=94 meaning the tail page would still be overwritten in = memmap_init_range()), the old code cannot be removed yet. It is cleaned up in the follow-up once = the switch is complete. Thanks, Muchun >=20 > -- > Cheers, >=20 > David