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 69BB0248176; Wed, 29 Oct 2025 01:53:16 +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=1761702796; cv=none; b=ld8zywf+bfwjgNFakmEZur29StdOS+FvR6ir0hvAudVaqmIIXEgKak4aFnpxT8B4G2hVw51wLq98REVie/54YdS+yPFXk/oz2/dnmvvMddOhhHllph9edCrmYoorXcfykhRO0N2gj8mjR30xvrGY0eCc4scL1DofV2/zJcBQhF8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761702796; c=relaxed/simple; bh=tY2c6NjA5+Sk9Tdpn18jcSFDKBACGQ7NeJaqRR/JFxA=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=SbAS3rLXt2ns4pUIVs2g9glZb3+ZXcYqgRxnLO+7yirSiuuMVl/rFAeqRvxFDpn4WulfX0/8eb5RmGA531b/9eWmn9LZdOZqqnNKTlSTJKOOTsA7Xo+QbR3S/BLwXKnEDiq3QQ0ErYp+GmxEDZYo5fAbVZhe8ACxpZu6UThTfWw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=b4kW6trY; 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="b4kW6trY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 64773C4CEE7; Wed, 29 Oct 2025 01:53:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761702796; bh=tY2c6NjA5+Sk9Tdpn18jcSFDKBACGQ7NeJaqRR/JFxA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=b4kW6trYvX6IXFW+O8/OQr9KM9ZVIcBYKyeEiZL53Bn9Mo7nue9Qe41YCn1zFxrrh jsxCNd3MNywTTxIsdslY2nYxrBt2c7MZHYiDvbuxHhERQXPzkMxfKdiuC/N8JUezLo rrPJsGPHZSYrBFhiFXXkVc3YiDY77C8Opw1R7Difil9Lic/ytPszan1Nt4P+YjFhH4 UAyR7WvnMX0rQPjFia69O4Eo+vs6I00+TvkHAYyzWDiiz/t77YaIIwT8UJwx74AAVV r4o6kkaYL1x6jnoeiYeFpEcIY/Y1Nl9vf5Eyk5oMx4ZF+lJ58msQTOuVIddhtHZbmj QT7VPS9A87A3A== Date: Tue, 28 Oct 2025 18:53:14 -0700 From: Jakub Kicinski To: Jesper Dangaard Brouer Cc: Maciej Fijalkowski , bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org, magnus.karlsson@intel.com, aleksander.lobakin@intel.com, ilias.apalodimas@linaro.org, toke@redhat.com, lorenzo@kernel.org, syzbot+ff145014d6b0ce64a173@syzkaller.appspotmail.com, Ihor Solodrai , Octavian Purdila Subject: Re: [PATCH v4 bpf 1/2] xdp: introduce xdp_convert_skb_to_buff() Message-ID: <20251028185314.1ad62578@kernel.org> In-Reply-To: <11142984-9bbe-4611-bbe7-fa5494036b8f@kernel.org> References: <20251027121318.2679226-1-maciej.fijalkowski@intel.com> <20251027121318.2679226-2-maciej.fijalkowski@intel.com> <11142984-9bbe-4611-bbe7-fa5494036b8f@kernel.org> 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 Tue, 28 Oct 2025 09:08:52 +0100 Jesper Dangaard Brouer wrote: > > + xdp->rxq->mem.type = page_pool_page_is_pp(virt_to_head_page(xdp->data)) ? > > + MEM_TYPE_PAGE_POOL : MEM_TYPE_PAGE_SHARED; > > We are slowly killing performance with these paper cuts. The > information we are looking for should be available via skb->pp_recycle, > but instead we go lookup the page to deref that memory. And plus the > virt_to_head_page() is more expensive than virt_to_page(). > > Why don't we check skb->pp_recycle first, and then fall-back to checking > the page to catch the mentioned problems? I still think _all_ frags which may end up here are from the per CPU PP since we CoW the skbs. So: DEBUG_NET_WARN_ON_ONCE(!skb->pp_recycle); xdp->rxq->mem.type = MEM_TYPE_PAGE_POOL; ? It is legal to have pp and non-pp frags in a single skb AFAIK.