From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 93DDF1632CA; Thu, 12 Dec 2024 05:04:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733979878; cv=none; b=ja7PNesJRCeoGK9nkD0U+9CnxEyCutmgaET2/9q6sBsZVMgecAWjdOJQI4nRpVI1w6DjnNCGFJMfSI9FwC+of7r82ZyDsVhmTjEky6dNVXGN7gunHfQGDgvQeoM35c2bh137RghdLJigWadIrXrWszxuCE3Zvg6YjchKFB9WxpI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733979878; c=relaxed/simple; bh=VEKVRBoe22J+1hv8PucOdmZQtu/cWRv25jx9p6mkVjA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=d+UBN/yZnqc1l2q/1QJY/qPBguO/3AQha6J2HHY1XOEQsTXkD9TehZcZFjYTJllU5cb1jduiFNpDmF86kaLG4gIEIzGHS1dHPgUnsddPzFP8pHNNPdXiyYgtxaUsr5lmBJcwpiwF1YZZitP85+vomHfnaDACqEmCPDPbFQTTGhc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=lKu5AYnG; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="lKu5AYnG" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Mkkj/z+6cVMqEWDiwe1t0JQPVqzn1IGN5HRxuZF7jNk=; b=lKu5AYnGUJqai2k9tax9eGs6FR y2yi6Tdnzdg/iMW/G593cApOV0DEgN3FoqFleQ6Fwsi0XCMXlVtjzWl42J5987nzsL8GH3PWH7m4M Iuq6FzI2GkpvFFR8lgNjoPQBjVJHwRRti2xp5iYvBFFCADzmGUk3e64HdBlU0SOf8S9u2YZW/oflb nnzpDMJazID2RX7qhR3Fd3AgbuvzbGkl17YmxHXof9o32c8mJUrgPRtwZ6V8jTOdvHvr4bKyRJu9G yRw9dsodpa1NdfKdyEnoGKF9UN4dkTBPG8WizyofmTPpzvGXMOhXL7NSJxJFkkavoSyFQ6E28NDC1 YzSrt0Kg==; Received: from hch by bombadil.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tLbNJ-0000000Gw1r-2vR6; Thu, 12 Dec 2024 05:04:33 +0000 Date: Wed, 11 Dec 2024 21:04:33 -0800 From: Christoph Hellwig To: Shivasharan S Cc: linux-pci@vger.kernel.org, bhelgaas@google.com, manivannan.sadhasivam@linaro.org, logang@deltatee.com, Jonathan.Cameron@huawei.com, linux-kernel@vger.kernel.org, sumanesh.samanta@broadcom.com, sathya.prakash@broadcom.com, sjeaugey@nvidia.com Subject: Re: [PATCH v3 2/2] PCI/P2PDMA: Modify p2p_dma_distance to detect P2P links Message-ID: References: <1733901468-14860-1-git-send-email-shivasharan.srikanteshwara@broadcom.com> <1733901468-14860-3-git-send-email-shivasharan.srikanteshwara@broadcom.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1733901468-14860-3-git-send-email-shivasharan.srikanteshwara@broadcom.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Tue, Dec 10, 2024 at 11:17:48PM -0800, Shivasharan S wrote: > Update the p2p_dma_distance() to determine inter-switch P2P links existing > between two switches and use this to calculate the DMA distance between > two devices. This requires enabling the PCIE_P2P_LINK config option in > the kernel. What the heck are "P2P links supposed to be. And why shoud Linux support something non-standard like this? NAK for these hacks to the core code unless you can get a vendor indpendent spec for it.