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Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uw3VC-0000000CmOd-2NmJ; Tue, 09 Sep 2025 18:55:38 +0000 Date: Tue, 9 Sep 2025 19:55:38 +0100 From: Matthew Wilcox To: Kefeng Wang Cc: Andrew Morton , David Hildenbrand , Oscar Salvador , Muchun Song , sidhartha.kumar@oracle.com, jane.chu@oracle.com, Zi Yan , Vlastimil Babka , Brendan Jackman , Johannes Weiner , linux-mm@kvack.org Subject: Re: [PATCH v2 6/9] mm: page_alloc: add alloc_contig_frozen_pages() Message-ID: References: <20250902124820.3081488-1-wangkefeng.wang@huawei.com> <20250902124820.3081488-7-wangkefeng.wang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250902124820.3081488-7-wangkefeng.wang@huawei.com> X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 6C6A44000D X-Stat-Signature: hnsj1tai1onasp57pf9axqbfcczt1f4c X-HE-Tag: 1757444149-312904 X-HE-Meta: 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 58t+1S+3 gyM/tlow7F2GBnV1BfpQxksGMlJgeg1KrJcqNwO1htpT+H2LZOFyPnqhOvmA6TbjhN0P/G13yOvaS03GbymB1j5fkgdm5qrs82y61WpeYc0ox6jfENcf5Sl1ANR9aNGlV16ZE/8ElM1EW30C0+midJoCwAku2cINQs9LJbGpVtwf67nuPEzlfKF3NeNlV8FnHI8H+Gpo7iOGkMuA725azO898lYW3XFFOOdcD X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Sep 02, 2025 at 08:48:17PM +0800, Kefeng Wang wrote: > Introduce a ACR_FLAGS_FROZEN flags to indicate that we want to > allocate a frozen compound pages by alloc_contig_range(), also > provide alloc_contig_frozen_pages() to allocate pages without > incrementing their refcount, which may be beneficial to some > users (eg hugetlb). No, this is not the way to do it. We're moving towards a future where pages don't have refcounts (their owning structs eg folios may have a refcount, but struct page does not have a refcount). So work towards that; if you need to keep compatibility with some users, then by all means keep alloc_contig_range_noprof() as a wrapper that calls alloc_contig_range_frozen_noprof() and then calls set_page_refcounted() if alloc_contig_range_frozen_noprof() does not return NULL. But I'd be looking to see if alloc_contig_range_noprof() can always return a non-refcounted page.