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[23.128.96.18]) by mx.google.com with ESMTP id g3si1508174edz.571.2021.10.07.19.13.02; Thu, 07 Oct 2021 19:13:28 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234468AbhJHCND (ORCPT + 99 others); Thu, 7 Oct 2021 22:13:03 -0400 Received: from mga06.intel.com ([134.134.136.31]:37004 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229501AbhJHCNC (ORCPT ); Thu, 7 Oct 2021 22:13:02 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10130"; a="287298679" X-IronPort-AV: E=Sophos;i="5.85,356,1624345200"; d="scan'208";a="287298679" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Oct 2021 19:11:07 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.85,356,1624345200"; d="scan'208";a="478804301" Received: from allen-box.sh.intel.com (HELO [10.239.159.118]) ([10.239.159.118]) by orsmga007.jf.intel.com with ESMTP; 07 Oct 2021 19:11:05 -0700 Cc: baolu.lu@linux.intel.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, arei.gonglei@huawei.com Subject: Re: [PATCH v3 2/2] iommu/vt-d: avoid duplicated removing in __domain_mapping To: "Longpeng(Mike)" , dwmw2@infradead.org, will@kernel.org, joro@8bytes.org References: <20211008000433.1115-1-longpeng2@huawei.com> <20211008000433.1115-3-longpeng2@huawei.com> From: Lu Baolu Message-ID: <54cf3663-85e0-3e63-9112-385e9d6eeceb@linux.intel.com> Date: Fri, 8 Oct 2021 10:07:17 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <20211008000433.1115-3-longpeng2@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/8/21 8:04 AM, Longpeng(Mike) wrote: > __domain_mapping() always removes the pages in the range from > 'iov_pfn' to 'end_pfn', but the 'end_pfn' is always the last pfn > of the range that the caller wants to map. > > This would introduce too many duplicated removing and leads the > map operation take too long, for example: > > Map iova=0x100000,nr_pages=0x7d61800 > iov_pfn: 0x100000, end_pfn: 0x7e617ff > iov_pfn: 0x140000, end_pfn: 0x7e617ff > iov_pfn: 0x180000, end_pfn: 0x7e617ff > iov_pfn: 0x1c0000, end_pfn: 0x7e617ff > iov_pfn: 0x200000, end_pfn: 0x7e617ff > ... > it takes about 50ms in total. > > We can reduce the cost by recalculate the 'end_pfn' and limit it > to the boundary of the end of this pte page. > > Map iova=0x100000,nr_pages=0x7d61800 > iov_pfn: 0x100000, end_pfn: 0x13ffff > iov_pfn: 0x140000, end_pfn: 0x17ffff > iov_pfn: 0x180000, end_pfn: 0x1bffff > iov_pfn: 0x1c0000, end_pfn: 0x1fffff > iov_pfn: 0x200000, end_pfn: 0x23ffff > ... > it only need 9ms now. > > Signed-off-by: Longpeng(Mike) > --- > drivers/iommu/intel/iommu.c | 11 ++++++----- > include/linux/intel-iommu.h | 6 ++++++ > 2 files changed, 12 insertions(+), 5 deletions(-) > > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c > index d75f59a..46edae6 100644 > --- a/drivers/iommu/intel/iommu.c > +++ b/drivers/iommu/intel/iommu.c > @@ -2354,12 +2354,17 @@ static void switch_to_super_page(struct dmar_domain *domain, > return -ENOMEM; > first_pte = pte; > > + lvl_pages = lvl_to_nr_pages(largepage_lvl); > + > /* It is large page*/ > if (largepage_lvl > 1) { > unsigned long end_pfn; > + unsigned long pages_to_remove; > > pteval |= DMA_PTE_LARGE_PAGE; > - end_pfn = ((iov_pfn + nr_pages) & level_mask(largepage_lvl)) - 1; > + pages_to_remove = min_t(unsigned long, nr_pages, > + nr_pte_to_next_page(pte) * lvl_pages); > + end_pfn = iov_pfn + pages_to_remove - 1; > switch_to_super_page(domain, iov_pfn, end_pfn, largepage_lvl); > } else { > pteval &= ~(uint64_t)DMA_PTE_LARGE_PAGE; > @@ -2381,10 +2386,6 @@ static void switch_to_super_page(struct dmar_domain *domain, > WARN_ON(1); > } > > - lvl_pages = lvl_to_nr_pages(largepage_lvl); > - > - BUG_ON(nr_pages < lvl_pages); > - > nr_pages -= lvl_pages; > iov_pfn += lvl_pages; > phys_pfn += lvl_pages; > diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h > index 9bcabc7..b29b2a3 100644 > --- a/include/linux/intel-iommu.h > +++ b/include/linux/intel-iommu.h > @@ -713,6 +713,12 @@ static inline bool first_pte_in_page(struct dma_pte *pte) > return IS_ALIGNED((unsigned long)pte, VTD_PAGE_SIZE); > } > > +static inline int nr_pte_to_next_page(struct dma_pte *pte) > +{ > + return first_pte_in_page(pte) ? BIT_ULL(VTD_STRIDE_SHIFT) : > + (struct dma_pte *)ALIGN((unsigned long)pte, VTD_PAGE_SIZE) - pte; We should make it like this to avoid the 0day warning: (struct dma_pte *)(uintptr_t)VTD_PAGE_ALIGN((unsigned long)pte) - pte; Can you please test this line of change? No need to send a new version. I will handle it if it passes your test. > +} > + > extern struct dmar_drhd_unit * dmar_find_matched_drhd_unit(struct pci_dev *dev); > extern int dmar_find_matched_atsr_unit(struct pci_dev *dev); > > Best regards, baolu