From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CFE7B262FFC; Fri, 7 Nov 2025 01:33:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762479205; cv=none; b=nStleW1gBe8G2B6xWPAy59Od0OpBk++EcIHVKznRDsK2EkGOUo+kXRVQCmbrBxdUAPM/YaTeeH6wUYZKGrpBDrFLSYuD7CAKmNaaV4zIC/yavtLF7RtwJ6mSDHOXPV+BnZeFxXAqohTVjNIkyDaVvXc8ponHoktDDn8LDMtvzik= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762479205; c=relaxed/simple; bh=PK7Z65DZGnYLDCAiL5Ph+9HVPYcOYAtAYKPp1a9+thY=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=dgUwFDBhe1NDhbiAJVuQSTbzL7w0PyTuMqJXUdKAgNPsW9yveaz+0k6QSqaX0RO+ucxV6RJk1qtL7DB9rwEey5x+CJCJEjCTOeeS/748HZHnDQxdPyWS2fQOXRn0rsQsNMejEp7a+oSBWlKZqDUPdA5JYYilR7VcoCpKqwNV3JY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HZDtFRxT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HZDtFRxT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2743CC116C6; Fri, 7 Nov 2025 01:33:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762479205; bh=PK7Z65DZGnYLDCAiL5Ph+9HVPYcOYAtAYKPp1a9+thY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=HZDtFRxTxzd3xikS/f+aycu7YIXmI9UGBNqjJz6+mH/rWmM5sdTd2jsJMxzcCdzq2 hyDD7hww9hoFo5X224lwyesdTFd3RRyYt3gp0GGgs7Uhe+GOyUeZZj+wSkl469Kh3q TSiNFhkZ6AAHXrCeg54DIWesWe6qwatLr5UXZ5XhbnUmacVzzwf79bZz9Zms3ooyP4 kcRrom2suZUgXqhwfDEcvFI1pUj4YyTVaUX2gMSPvI/uC0JfIDRpT/WRkIDWLW9HBm 82ZMVREYe5M7qwXkVriF+ggbDIg/oN1dLDh3xCTKsX1Ko0LLnuHQ4/BSTEO0jOzvab LPE5mWFmXkW7g== Date: Thu, 6 Nov 2025 17:33:20 -0800 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 v5 1/2] page_pool: check nmdesc->pp to see its usage as page pool for net_iov not page-backed Message-ID: <20251106173320.2f8e683a@kernel.org> In-Reply-To: <20251103075108.26437-2-byungchul@sk.com> References: <20251103075108.26437-1-byungchul@sk.com> <20251103075108.26437-2-byungchul@sk.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 3 Nov 2025 16:51:07 +0900 Byungchul Park wrote: > 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. Please explain why. Isn't the type just a value in a field? Which net_iov could also set accordingly.. ?