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Mon, 03 Nov 2025 04:24:41 -0800 (PST) X-Google-Smtp-Source: AGHT+IFL2sLtytpLuUcKWCOkoRDcXckWNNb+evONxAWiMkrqYHa0li9xt3zPEufFR+6cGkgmgzhx/A== X-Received: by 2002:a17:907:6d20:b0:b70:b83a:73e5 with SMTP id a640c23a62f3a-b70b83a8c35mr359778466b.44.1762172681211; Mon, 03 Nov 2025 04:24:41 -0800 (PST) Received: from alrua-x1.borgediget.toke.dk ([45.145.92.2]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-6407b392d5dsm9676772a12.15.2025.11.03.04.24.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Nov 2025 04:24:40 -0800 (PST) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id EE02432844E; Mon, 03 Nov 2025 13:24:39 +0100 (CET) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Byungchul Park , linux-mm@kvack.org, netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel_team@skhynix.com, harry.yoo@oracle.com, ast@kernel.org, daniel@iogearbox.net, davem@davemloft.net, kuba@kernel.org, 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, 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 v5 1/2] page_pool: check nmdesc->pp to see its usage as page pool for net_iov not page-backed In-Reply-To: <20251103075108.26437-2-byungchul@sk.com> References: <20251103075108.26437-1-byungchul@sk.com> <20251103075108.26437-2-byungchul@sk.com> X-Clacks-Overhead: GNU Terry Pratchett Date: Mon, 03 Nov 2025 13:24:39 +0100 Message-ID: <87ms53pam0.fsf@toke.dk> MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: ZSYtqjb_FAxhrfgbA-MONAYG48Tid1u9BoUzw3n6DeY_1762172682 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Stat-Signature: rj4ipq1m1n55a3ijo1c7yeg7scmgzcj4 X-Rspamd-Queue-Id: CFF2C80004 X-Rspamd-Server: rspam06 X-Rspam-User: X-HE-Tag: 1762172684-878287 X-HE-Meta: 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 xc8HPjrM e7bAu7SdlKYMljbgsZdk59JR82LnpfOG2TV/xmMWvJa9W4kUjXAT9xbh8pXoN3ZMa8sL6Rw76t6hmUEm2tbjKD6UCvYQLKyXabu7Tunif+g6Vu/JEYlG1AR5GmLi5t9ORMAUGZL+P4RTPc4cUozTP9V896uXorFVIk52NCV+i/UeQa7+mGNfKtp6/rPgXqA1oa6hbuitOjRMsMBnsIIY0djwThfGISfVdsl/aSxxapUHdOF6nRry7c9tkQf7bzhv4ax6aq2QXu9R+4ArEJ4rWYo8oaW1ElF7fOpsdWnvnh/o3/FZo5+Q5c9Ey8B5wnL4U2GruoaT/lUm49/e9Jhezt1MI7UGdrk3yZVT6GLDcvL2jp5GMI6pLtiN4YBnBurl2+EjwHyBgm13qW8BRA4KFrFmdnz9BWeRGvShY5ftl1kn4zrU3CFzgRzymBEYjwAYC+eyPjtCTVFra410PeN04Vf3/25QiCAk1VXTnRBc8oTFKCJBF3BPwuc5a/eYexZN819aIvWyaOMJNbbW/GzHILZKhkKntN8XQ/J2eVFPNWcmWg46dW3L9puUPupycaQEqVzev6Zq1j1+9m5BXsg8YQkTIXPV9akZ77Bh4TomEOxd1mWZUVc2iVOC3vdmHr/hcaN6oztdm0bH0CUBCvqfumMbL4JGzO9AXxaVbYbF4yBhA2/eXwqE7iwxGUU5EBBUTypHJqzFJNpYGr4UnHXV5hximinmLGHMAFRS0trIUdyQuekiqtTxfylBlNA== 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: Byungchul Park writes: > Currently, the condition 'page->pp_magic =3D=3D PP_SIGNATURE' is used to > determine if a page belongs to a page pool. However, with the planned > removal of ->pp_magic, we will instead leverage the page_type in struct > page, such as PGTY_netpp, for this purpose. > > That works for page-backed network memory. However, for net_iov not > page-backed, the identification cannot be based on the page_type. > Instead, nmdesc->pp can be used to see if it belongs to a page pool, by > making sure nmdesc->pp is NULL otherwise. > > For net_iov not page-backed, initialize it using nmdesc->pp =3D NULL in > net_devmem_bind_dmabuf() and using kvmalloc_array(__GFP_ZERO) in > io_zcrx_create_area() so that netmem_is_pp() can check if nmdesc->pp is > !NULL to confirm its usage as page pool. > > Signed-off-by: Byungchul Park > Reviewed-by: Mina Almasry Reviewed-by: Toke H=C3=B8iland-J=C3=B8rgensen