From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752046AbeEGH7Z (ORCPT ); Mon, 7 May 2018 03:59:25 -0400 Received: from 8bytes.org ([81.169.241.247]:58644 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751940AbeEGH7W (ORCPT ); Mon, 7 May 2018 03:59:22 -0400 Date: Mon, 7 May 2018 09:59:21 +0200 From: Joerg Roedel To: Thierry Reding Cc: Dmitry Osipenko , Jonathan Hunter , iommu@lists.linux-foundation.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v1 4/4] iommu/tegra: gart: Optimize map/unmap Message-ID: <20180507075920.GA18595@8bytes.org> References: <20180427100202.GO30388@ulmo> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180427100202.GO30388@ulmo> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 27, 2018 at 12:02:02PM +0200, Thierry Reding wrote: > Joerg, I've gone over the git log and header files and I see no mention > of why the TLB flush interface isn't used for mapping. Do you recall any > special reasons why the same shouldn't be applied for mapping? Would you > accept any patches doing this? Yeah, the reason was that we assumed that only emulated IOMMUs ever need flushing in the mapping path, and there is no reason to optimize for that. Especially when a call to iotlb_sync() in the mapping path would hurt most other users. Does the tegra-gart actually need it too? Joerg