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Miller" , Muchun Song , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, loongarch@lists.linux.dev, sparclinux@vger.kernel.org, Alexandre Ghiti , Albert Ou , WANG Xuerui , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko Subject: Re: [PATCH v3 1/5] mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and vmemmap_check_pmd() Message-ID: References: <20260601084845.3792171-1-songmuchun@bytedance.com> <20260601084845.3792171-2-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260601084845.3792171-2-songmuchun@bytedance.com> X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 9EDC9C0004 X-Stat-Signature: tmcrffk1omz71u31rep48na97xqq9job X-Rspam-User: X-HE-Tag: 1780375283-985723 X-HE-Meta: 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 3Br9f25G qRa9lcxvK0Pv8WrioVsxF+ld5xXW0CMhi4+FoNtg65efzLguTy1aE20dDT73Av4h8KJCml0my5SQFZJHjX4LPq5ojZrWECxEJS6iWPe+2Op/sdttY9PxO4i+gkfOL/CG2YEYDwB0N9PdEEvSvvxZZMDZ07Z7dpF///B/5ca8OSsOwS8IWAuAlFKvOI1G8QrGr76GzBTHP52yesG7hds9xtxnK1vOhu04moEkaRXpur4/d+/M0E2lWjmvvdChmpZDL9D4DppVZLAPx9b0//fxJibBz3v9mOTXq1DOTfzZSqxz2QCT1TjuHM2EZ7w== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Jun 01, 2026 at 04:48:40PM +0800, Muchun Song wrote: > The two weak functions are currently no-ops on every architecture, > forcing each platform that needs them to duplicate the same handful > of lines. Provide a generic implementation: > > - vmemmap_set_pmd() simply sets a huge PMD with PAGE_KERNEL protection. > > - vmemmap_check_pmd() verifies that the PMD is present and leaf, > then calls the existing vmemmap_verify() helper. > > Architectures that need special handling can continue to override the > weak symbols; everyone else gets the standard version for free. > > Signed-off-by: Muchun Song Acked-by: Oscar Salvador (SUSE) -- Oscar Salvador SUSE Labs