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 A4B5D2D0637; Wed, 29 Oct 2025 01:33:59 +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=1761701640; cv=none; b=YRvLjjpXdjyDkWgLBB+IIZXtv8AYamcGiaVwp5JN61GLpgQyeyZWeG4oxvDjxrZsGIfl+4Q9IEAFTVUtvxdQP849Ym+TDqLgv6I4sfEnfgRlIaq2bF8DajVxvYW86Nx58hg1bNvh21M6KkxoVz9M87m0cYvfUg4Q0WETxchg/Rg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761701640; c=relaxed/simple; bh=z3Yc/tloRcuK+HMyEVQv+U3jCVDjfWF9XOBpQagP+cI=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=KzLkxx8dVGWLz4CO2/83tiQpb0ap2OSOcSJJ94l3WeL7ExNhggunkMByOaKs8Uql2lLmqaxTPzcRu7SD6uOQrWPdZDnFsz0XHGddZwqFREsKgZNNpiHf8DIcfCwC9iTUwymWt06gSBv6+5lrUzZ3t0XXv6LY5Uhw/49iNpl9VTg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=i2CacSQj; 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="i2CacSQj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EA927C4CEE7; Wed, 29 Oct 2025 01:33:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761701639; bh=z3Yc/tloRcuK+HMyEVQv+U3jCVDjfWF9XOBpQagP+cI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; 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> Precedence: bulk X-Mailing-List: linux-rdma@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 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.