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h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=mShnAkf/k0d/LPFZwfdKiBYhDDRse6tKDagf1kPr0oc2h9w/psRVyY/VbUi3fNrb/ UwejrwtODpxGK4z79tPZavt95SOnbd9sQLRlk39P65hH7VVNgNbtEk/e5DbB/+7/bP 5B1vSYWraZaEkPnl8p2FqY/yFJPFQwjm9t9YWKptwjSJFVpG65JiB+ZDSD1GSyxYHm xfrrdmbqoXEBePOAjVHkqhnlYkckawhDLioIf+F6YK0jJTGJ2OKAppfEQDJOnhw7xM N678+2fkcGmpwmOX8M7g5QP1A2k0MROxHaQA2BcOtjrzzDO/BD8NZq4JkLEC3Lb2Fq 4WwEwNJCm7Zrw== Received: by mail-qv1-f43.google.com with SMTP id 6a1803df08f44-8a23f802e0cso3916956d6.1 for ; Wed, 08 Apr 2026 14:29:37 -0700 (PDT) X-Gm-Message-State: AOJu0Yw+ES/vBhhUJN24+Y/HEQnzxZ2gDJAaY7nA45lciuQN4EFBP05U 1W1SS4fkq2bzZXBofdJWjF0/A9G7Gs1zJx1mkb9I9koeFje4bpUga5+ldrjZI/vfZ6OIABDV5+/ 8q4rsNV9yLetVlfYJ82KN5sgiy8vs2s4= X-Received: by 2002:a05:6214:1d0a:b0:8ac:74d7:dd14 with SMTP id 6a1803df08f44-8ac74d7debcmr15884866d6.34.1775683776598; Wed, 08 Apr 2026 14:29:36 -0700 (PDT) MIME-Version: 1.0 References: <20260408025115.27368-1-baohua@kernel.org> <20260408025115.27368-4-baohua@kernel.org> In-Reply-To: From: Barry Song Date: Thu, 9 Apr 2026 05:29:25 +0800 X-Gmail-Original-Message-ID: X-Gm-Features: AQROBzDD8xzlg0Uj1HRs0Wqi-s5iSaX2fFmsZNIkL6fa0v5sA5A7gsWqrrxGDtU Message-ID: Subject: Re: [RFC PATCH 3/8] mm/vmalloc: Extend vmap_small_pages_range_noflush() to support larger page_shift sizes To: Dev Jain Cc: linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will@kernel.org, akpm@linux-foundation.org, urezki@gmail.com, linux-kernel@vger.kernel.org, anshuman.khandual@arm.com, ryan.roberts@arm.com, ajd@linux.ibm.com, rppt@kernel.org, david@kernel.org, Xueyuan.chen21@gmail.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: E0E75140006 X-Stat-Signature: i4tk6sf84uidj9cwkwwyfc9uwtygs7pp X-Rspam-User: X-HE-Tag: 1775683778-142236 X-HE-Meta: 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 jTL8OoJz bZlqP8up3nQ0NBHsWgVduRzre6nGq9I5FuF92dkiXpG54ny2mQAAV7ax+XJKmA2K89voPGsyQgXqydBoL9/A1fw0dNsVPLNOVBQCwMw1t6AH8nmEKSicpTDV5hfHtXHoV9ogJq5vvvq/ceVnfe9lhFTHuqwocLfJ/mD3OUIn5iqpMtgM9bAEllV5pGOqdunCQvPdzClKuts8Hsfe8TQIvs9ralVi565iB1gFye8SY+iuZRtkqt5t0r2ntEwKa0KSY6Te/YjYj/APyft/9M24seVJKTQzQGeqLejIX4goeI4FJhWMyKWgfd4OU6s+xn108Uhgf65aIS1WhUA8HXkKeiCCY4tHYjvHPd08PnRTWHEaI+3fLfdVwssI0NiAWhFKDLfu5htEqNiP2NdHPl9Jnw920DAJAjZ+6xiDIUAJBBPPrSQhtS2u1SC0jWN1NMdKn8r8JeQL1lRu1/RA= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Apr 8, 2026 at 7:08=E2=80=AFPM Dev Jain wrote: > > > > On 08/04/26 8:21 am, Barry Song (Xiaomi) wrote: > > vmap_small_pages_range_noflush() provides a clean interface by taking > > struct page **pages and mapping them via direct PTE iteration. This > > avoids the page table zigzag seen when using > > "Zigzag" is ambiguous. Just say "page table rewalk". Also please > elaborate on why the rewalk is happening currently. Sure=E2=80=94I=E2=80=99m not a native speaker, but =E2=80=9Czigzag=E2=80=9D= feels like =E2=80=9Crepeatedly walking the page tables back and forth=E2=80=9D to me. That=E2=80=99s exactly what I want to express. > > > vmap_range_noflush() for page_shift values other than PAGE_SHIFT. > > > > Extend it to support larger page_shift values, and add PMD- and > > contiguous-PTE mappings as well. > > So we can drop the "small" here since now it supports larger chunks > as well. I=E2=80=99m still struggling with the name, since we already have a function without =E2=80=9Csmall=E2=80=9D here: int vmap_pages_range_noflush(unsigned long addr, unsigned long end, pgprot_t prot, struct page **pages, unsigned int page_shift= , gfp_t gfp_mask) > > Also at this point the code you add is a no-op since you pass PAGE_SHIFT. > Let us just squash patch 4 into this. This patch looks weird retaining > the pagetable-rewalk algorithm when it literally adds functionality > to avoid that. Sure. will do. Thanks Barry