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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1EAF7C433EF for ; Fri, 8 Oct 2021 02:47:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 02BC3610CC for ; Fri, 8 Oct 2021 02:47:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235351AbhJHCth (ORCPT ); Thu, 7 Oct 2021 22:49:37 -0400 Received: from mga09.intel.com ([134.134.136.24]:36230 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229559AbhJHCtg (ORCPT ); Thu, 7 Oct 2021 22:49:36 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10130"; a="226320660" X-IronPort-AV: E=Sophos;i="5.85,356,1624345200"; d="scan'208";a="226320660" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Oct 2021 19:47:41 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.85,356,1624345200"; d="scan'208";a="478812854" 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 19:47:39 -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> <54cf3663-85e0-3e63-9112-385e9d6eeceb@linux.intel.com> From: Lu Baolu Message-ID: <1e83751f-5731-5786-c7d7-899542d7c2b7@linux.intel.com> Date: Fri, 8 Oct 2021 10:43:51 +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: <54cf3663-85e0-3e63-9112-385e9d6eeceb@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/8/21 10:07 AM, Lu Baolu wrote: > 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. Just realized that ALIGN() has already done the type cast. Please ignore above comment. Sorry for the noise. Best regards, baolu