From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 806FFC3815B for ; Mon, 20 Apr 2020 08:10:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53CD820A8B for ; Mon, 20 Apr 2020 08:10:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="kaM0tk5W" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725865AbgDTIKj (ORCPT ); Mon, 20 Apr 2020 04:10:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47274 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725773AbgDTIKj (ORCPT ); Mon, 20 Apr 2020 04:10:39 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 88D3AC061A0C; Mon, 20 Apr 2020 01:10:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; 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=C1JU5+id39RVYYiwVLrKINx5vf4t7nToazXLCIKWefE=; b=kaM0tk5W81sI2+qX4Q+fhFqknM bURUCNk0t2z/tH3hUWbh5Ya9slhk5rLszSWU71wkyFyy7q2Tqtylx0B1qa4oBZPhzl1Pzd0n9iYI8 U7EmgJ8u5DWdLj8f4XGdJLn1gEer0ExVNct3iwrHWd6KEFcS/i5dzVd1+giEP2fKM0YZ5nI94pJGU bLc0GipQGkEljB04yFayRugJ2xmfUknk0m5ohkt5kM/71a59PYsDPRLMCziNvX2mPRoqrCALoAuOB x+Diqoon7jrr1Snwm2VWR5aH9n2Hpqx5jH6fbbjyms2QLla8aBMh0zsJvsuQdVSIVR0dIm7P9QRvO X5rQmNQQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jQRVi-0007EB-H6; Mon, 20 Apr 2020 08:10:34 +0000 Date: Mon, 20 Apr 2020 01:10:34 -0700 From: Christoph Hellwig To: Jean-Philippe Brucker Cc: Christoph Hellwig , iommu@lists.linux-foundation.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, joro@8bytes.org, catalin.marinas@arm.com, will@kernel.org, robin.murphy@arm.com, kevin.tian@intel.com, baolu.lu@linux.intel.com, Jonathan.Cameron@huawei.com, jacob.jun.pan@linux.intel.com, christian.koenig@amd.com, zhangfei.gao@linaro.org, jgg@ziepe.ca, xuzaibo@huawei.com Subject: Re: [PATCH v5 02/25] iommu/sva: Manage process address spaces Message-ID: <20200420081034.GA17305@infradead.org> References: <20200414170252.714402-1-jean-philippe@linaro.org> <20200414170252.714402-3-jean-philippe@linaro.org> <20200416072852.GA32000@infradead.org> <20200416085402.GB1286150@myrica> <20200416121331.GA18661@infradead.org> <20200420074213.GA3180232@myrica> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200420074213.GA3180232@myrica> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Mon, Apr 20, 2020 at 09:42:13AM +0200, Jean-Philippe Brucker wrote: > Right, I can see the appeal. I still like having a single mmu notifier per > mm because it ensures we allocate a single PASID per mm (as required by > x86). I suppose one alternative is to maintain a hashtable of mm->pasid, > to avoid iterating over all bonds during allocation. Given that the PASID is a pretty generic and important concept can we just add it directly to the mm_struct and allocate it lazily once we first need it?