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Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Qi Zheng , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, muchun.song@linux.dev Subject: Re: [PATCH v3 0/6] mm: Unify device DAX and HugeTLB vmemmap population paths Message-Id: <20260929143214.9061bcf284369163192968d1@linux-foundation.org> In-Reply-To: <20260929053231.66085-1-songmuchun@bytedance.com> References: <20260929053231.66085-1-songmuchun@bytedance.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: hw9mtfcif7cmaqhmj87tox6387wppqe6 X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 6440120007 X-HE-Tag: 1790717537-334080 X-HE-Meta: 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 gI37uUbf KRt+KOei13H8g+iiuba6VEDJJxq4QuQuG9TJ/fqgG3RqwtZEbAb5FnwZKzwaFa4mHHAz4z80zCLLJkHKL/nUTMgu1ijs2bzvh7TJqNK+jusEdGyXbc799qwE8v7HLGQTdK17c+5OR7FI54nQDhLdcFbWF9h5FkEJuKv2sXLiuyJiaQ4b0qUwd2UcRqe01om7fNSD+1qerOOHSMTouoCet4gJVgBAQAeXBNGJT6K2P2lpQaL2MvFnKyFfuQt2nyzzizwwkU+aZKKQffyhXIMjcYNF4Xx9XXbSUHjK+wGXXq56DHEcSG2cHX0bKeBaFdYQ+/vrSAGYVfBFwouf7QPqmDx4AJXYP4MoQvZa2 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 29 Sep 2026 13:32:25 +0800 Muchun Song wrote: > This v3 is based on mm-new commit 2ddb90ee544a, which contains v5 of > "mm: Switch device DAX to section-based vmemmap optimization" [1]. > > This series is split out from the earlier, larger series "mm: Generalize > HVO for HugeTLB and device DAX" [2]. While the parent series generalizes > vmemmap optimization across HugeTLB and device DAX, this subset addresses > a single, self-contained step: unifying their vmemmap population paths. > > After the preceding Device DAX conversion, both HugeTLB and Device DAX > describe optimized vmemmap mappings through memory-section metadata and > use per-zone shared tail vmemmap pages. The generic code, however, still > carries a Device DAX-specific population flag and compound-page population > path, along with arguments and helpers needed only by that path. > > This series first removes VMEMMAP_POPULATE_DAX and moves selection and > reference handling for the shared tail page into the common vmemmap > population path. It then removes the generic Device DAX-specific > compound-page population path and routes section vmemmap population > through vmemmap_populate(). The powerpc radix path continues to use its > architecture-specific compound-page population implementation for > optimizable sections. > > The remaining patches remove the unused ptpfn argument, open-code > vmemmap_populate_address() now that no caller needs its returned PTE, and > add a warning for inconsistent zone initialization of shared tail vmemmap > pages. > > This is the fourth smaller step toward the broader HVO generalization. > After this series, HugeTLB and Device DAX use the same population model > instead of parallel generic paths, while powerpc keeps its > architecture-specific implementation. afaict the whole series is "no functional changes intended". Apart from [6/6]'s new WARN_ON. And [3/6] is the one which could cause unintended fuctional changes! Thanks. I'll queue it. Reluctantly. We're up to 688 MM patches this cycle and it's time to stop.