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b=i2CacSQjHmj9Ut0QvjXn1yYD5TGTQrCJ7pqAe6TCS1ETgHaXGlSxkPdPXJENowIKr 0dcWqbsoOMUnEU/I/CruVsiu1FngyDTvYg1X16idYC/1Zs+zy+SVhrgEe3k78xr5pA n7QZZPCDOwjpz9h+DjS1S8uEFVcNmIbOSYJRD/BA2OloR2NxGyUW01F57/MCKEW5a9 bpQNcHPzyY7lIbPHuF2Ra5gUjlMSH29F+lI24DtTJLkpiWgvBjqg21XETQYbfePRvw N/q2GamWYah9nYQeCmC+MHDHZb9qHEGFecyQ9MMnrAcDfUTGTfZye0kTc6deTq4r76 MiSZKe7WozKrw== Date: Tue, 28 Oct 2025 18:33:56 -0700 From: Jakub Kicinski To: Byungchul Park Cc: linux-mm@kvack.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kernel_team@skhynix.com, harry.yoo@oracle.com, ast@kernel.org, daniel@iogearbox.net, davem@davemloft.net, hawk@kernel.org, john.fastabend@gmail.com, sdf@fomichev.me, saeedm@nvidia.com, leon@kernel.org, tariqt@nvidia.com, mbloch@nvidia.com, andrew+netdev@lunn.ch, edumazet@google.com, pabeni@redhat.com, akpm@linux-foundation.org, david@redhat.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, horms@kernel.org, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, ilias.apalodimas@linaro.org, willy@infradead.org, brauner@kernel.org, kas@kernel.org, yuzhao@google.com, usamaarif642@gmail.com, baolin.wang@linux.alibaba.com, almasrymina@google.com, toke@redhat.com, asml.silence@gmail.com, bpf@vger.kernel.org, linux-rdma@vger.kernel.org, sfr@canb.auug.org.au, dw@davidwei.uk, ap420073@gmail.com, dtatulea@nvidia.com Subject: Re: [RFC mm v4 1/2] page_pool: check if nmdesc->pp is !NULL to confirm its usage as pp for net_iov Message-ID: <20251028183356.29601348@kernel.org> In-Reply-To: <20251023074410.78650-2-byungchul@sk.com> References: <20251023074410.78650-1-byungchul@sk.com> <20251023074410.78650-2-byungchul@sk.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: pe359okgihbfrxig6de7eedb7yg6bbz5 X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 46FD540006 X-HE-Tag: 1761701640-487519 X-HE-Meta: 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 Tem/NRko 8IYPpr6XE/gfs+/1BzALGbmhADj3HhxhHG6WruImF/XFqCVv440UfNL+QGjOfBGVA0raXJKWromz+SWw6jsL4sCfI6yLJ23a5Z8tkMPmVHNt2wgpUQ2yNhrj2A61rnFtbQrEHGI9z/2ml9AokE12jcAJKSpvQ6Ob150MtvwvaQSlWTYRKENHgMGuLs0wRD5VzlxTE0M5xErEpY6EZUODvzqt8d/cfA+yVyEGSXIUhINfNeehsyk+3T9fissNrlB6SZMZEX+c4e/0cVo5hARsBSQzXC5pFTQfJ77qbsAMNHIk4VcBP6CXFDI8/E9jgGBYuyxECKJf2TsPsb7/k8mdb/X/bbYLjIVrFeV6TPK1356XHrHFiCOxeecpkWVwyRKdUuPA1ORq6UDwog0bm5abj4SPRtdLLo35V67w2Y3ITYiCkbrqfRtvUzjOoSk/Lk6pL1yri2D0sZn0QVtNQo9j+eCxiHXb0OYlGhUI1 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 Thu, 23 Oct 2025 16:44:09 +0900 Byungchul Park wrote: > As a preparation, the check for net_iov, that is not page-backed, should > avoid using ->pp_magic since net_iov doens't have to do with page type. doesn't > Instead, nmdesc->pp can be used if a net_iov or its nmdesc belongs to a > page pool, by making sure nmdesc->pp is NULL otherwise. Please explain in the commit message why the new branch in netmem_is_pp() is necessary. We used to identify the pages based on PP_SIGNATURE, now we identify them based on page_type.