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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 BE867C432C0 for ; Wed, 27 Nov 2019 18:01:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9CB7020872 for ; Wed, 27 Nov 2019 18:01:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727090AbfK0SBB (ORCPT ); Wed, 27 Nov 2019 13:01:01 -0500 Received: from lhrrgout.huawei.com ([185.176.76.210]:2130 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726576AbfK0SBB (ORCPT ); Wed, 27 Nov 2019 13:01:01 -0500 Received: from LHREML710-CAH.china.huawei.com (unknown [172.18.7.107]) by Forcepoint Email with ESMTP id 27BC0BDB9FE9DE7501A4; Wed, 27 Nov 2019 18:01:00 +0000 (GMT) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by LHREML710-CAH.china.huawei.com (10.201.108.33) with Microsoft SMTP Server (TLS) id 14.3.408.0; Wed, 27 Nov 2019 18:00:59 +0000 Received: from [127.0.0.1] (10.202.226.46) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Wed, 27 Nov 2019 18:00:59 +0000 Subject: Re: [PATCH 1/3] iommu: match the original algorithm To: Cong Wang , CC: References: <20191121001348.27230-1-xiyou.wangcong@gmail.com> <20191121001348.27230-2-xiyou.wangcong@gmail.com> From: John Garry Message-ID: <9ac29292-bc3d-ae57-daff-5b3264020fe2@huawei.com> Date: Wed, 27 Nov 2019 18:00:58 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: <20191121001348.27230-2-xiyou.wangcong@gmail.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.226.46] X-ClientProxiedBy: lhreml720-chm.china.huawei.com (10.201.108.71) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21/11/2019 00:13, Cong Wang wrote: > The IOVA cache algorithm implemented in IOMMU code does not > exactly match the original algorithm described in the paper. > > Particularly, it doesn't need to free the loaded empty magazine > when trying to put it back to global depot. > > This patch makes it exactly match the original algorithm. > I haven't gone into the details, but this patch alone is giving this: root@(none)$ [ 123.857024] kmemleak: 8 new suspected memory leaks (see /sys/kernel/debug/kmemleak) root@(none)$ cat /sys/kernel/debug/kmemleak unreferenced object 0xffff002339843000 (size 2048): comm "swapper/0", pid 1, jiffies 4294898165 (age 122.688s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<000000001d2710bf>] kmem_cache_alloc+0x188/0x260 [<00000000cc229a78>] init_iova_domain+0x1e8/0x2a8 [<000000002646fc92>] iommu_setup_dma_ops+0x200/0x710 [<00000000acc5fe46>] arch_setup_dma_ops+0x80/0x128 [<00000000994e1e43>] acpi_dma_configure+0x11c/0x140 [<00000000effe9374>] pci_dma_configure+0xe0/0x108 [<00000000f614ae1e>] really_probe+0x210/0x548 [<0000000087884b1b>] driver_probe_device+0x7c/0x148 [<0000000010af2936>] device_driver_attach+0x94/0xa0 [<00000000c92b2971>] __driver_attach+0xa4/0x110 [<00000000c873500f>] bus_for_each_dev+0xe8/0x158 [<00000000c7d0e008>] driver_attach+0x30/0x40 [<000000003cf39ba8>] bus_add_driver+0x234/0x2f0 [<0000000043830a45>] driver_register+0xbc/0x1d0 [<00000000c8a41162>] __pci_register_driver+0xb0/0xc8 [<00000000e562eeec>] sas_v3_pci_driver_init+0x20/0x28 unreferenced object 0xffff002339844000 (size 2048): comm "swapper/0", pid 1, jiffies 4294898165 (age 122.688s) [snip] And I don't feel like continuing until it's resolved.... Thanks, John > Cc: Joerg Roedel > Signed-off-by: Cong Wang > --- > drivers/iommu/iova.c | 14 ++++++++------ > 1 file changed, 8 insertions(+), 6 deletions(-) > > diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c > index 41c605b0058f..92f72a85e62a 100644 > --- a/drivers/iommu/iova.c > +++ b/drivers/iommu/iova.c > @@ -900,7 +900,7 @@ static bool __iova_rcache_insert(struct iova_domain *iovad, > > if (!iova_magazine_full(cpu_rcache->loaded)) { > can_insert = true; > - } else if (!iova_magazine_full(cpu_rcache->prev)) { > + } else if (iova_magazine_empty(cpu_rcache->prev)) { > swap(cpu_rcache->prev, cpu_rcache->loaded); > can_insert = true; > } else { > @@ -909,8 +909,9 @@ static bool __iova_rcache_insert(struct iova_domain *iovad, > if (new_mag) { > spin_lock(&rcache->lock); > if (rcache->depot_size < MAX_GLOBAL_MAGS) { > - rcache->depot[rcache->depot_size++] = > - cpu_rcache->loaded; > + swap(rcache->depot[rcache->depot_size], cpu_rcache->prev); > + swap(cpu_rcache->prev, cpu_rcache->loaded); > + rcache->depot_size++; > } else { > mag_to_free = cpu_rcache->loaded; > } > @@ -963,14 +964,15 @@ static unsigned long __iova_rcache_get(struct iova_rcache *rcache, > > if (!iova_magazine_empty(cpu_rcache->loaded)) { > has_pfn = true; > - } else if (!iova_magazine_empty(cpu_rcache->prev)) { > + } else if (iova_magazine_full(cpu_rcache->prev)) { > swap(cpu_rcache->prev, cpu_rcache->loaded); > has_pfn = true; > } else { > spin_lock(&rcache->lock); > if (rcache->depot_size > 0) { > - iova_magazine_free(cpu_rcache->loaded); > - cpu_rcache->loaded = rcache->depot[--rcache->depot_size]; > + swap(rcache->depot[rcache->depot_size - 1], cpu_rcache->prev); > + swap(cpu_rcache->prev, cpu_rcache->loaded); > + rcache->depot_size--; > has_pfn = true; > } > spin_unlock(&rcache->lock); >