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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 32EF3C433DB for ; Thu, 18 Mar 2021 17:45:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 036EF64F1C for ; Thu, 18 Mar 2021 17:45:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232285AbhCRRpF (ORCPT ); Thu, 18 Mar 2021 13:45:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40998 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230173AbhCRRpB (ORCPT ); Thu, 18 Mar 2021 13:45:01 -0400 Received: from mail-qt1-x834.google.com (mail-qt1-x834.google.com [IPv6:2607:f8b0:4864:20::834]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 67527C06174A for ; Thu, 18 Mar 2021 10:45:01 -0700 (PDT) Received: by mail-qt1-x834.google.com with SMTP id m7so4687011qtq.11 for ; Thu, 18 Mar 2021 10:45:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=/cC0KVk2XWbXM3Otj4QsoyPSVbzBYQOGnqzN6CjxIbE=; b=FeXkUZk/+jDkciewd2ndeEV3yUAZPtXfx1KYDp4l1woVuAd0/6XTG7mKJI2sKXW/Ix fLQvPaJaIYLZvRE3U8DS4bIWeV132hq3TBcWMF/PyfxbqjcANpCVVc+amyvqYMp43ONv I/xsmzk8GXlHC1vjq+FQfsWJpcYAkU71FxL2bXyFU7PQ6pXxcYQ83nfdGCO4Vm/Xl84Z VkZyKl8IUEPgKrE0/hsbVeirVo5i6VtmEox3I7aRFOn4FlR1g3ymDhIKOBMxQZrf/tdx OZaLvT1uw3fy05pZI8twJusIBMaEq0DUhFGV3Fkq/pf2jh4iFNsyC8khGrztvBUPaVGs bIxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=/cC0KVk2XWbXM3Otj4QsoyPSVbzBYQOGnqzN6CjxIbE=; b=g3vkVvE3goBX9X6h8p8rYpkPnHHg0aUn5yOVkFOUBPoYu60hdlFxDROQYDJpju1yNY 2xEjFFdJI+FoDZEYAUYvZLcB5xn1R/R4cRfbBjOxcZTtm6fZTIrn0Q7JsCwDk8VibCvZ dPXmosOD//rFwCcDj+gO9gPHVE4T7fvF7SMgHQg85I1QyRs0zA9N8vhdSOQ5OKuj03+V m7jDVrMc66wFslGBP188Z+kZiZYfCnnt1oQcYY3cOJuyJMux7MhMFsr4MHrrYI0gWVbM X1NV7x3GKbxCSTrtfxbwzGw94ywq+bijjwopqTWd3nb1TmW2M94SJJrwfIBLcUq3/Rdb 5ycA== X-Gm-Message-State: AOAM5320k3coCr05I4270h8MvXauwAS/XzmKJUpO9xR8EHYf7fFoa3DK dNjtpUALuEQQ9eFDRghi+S4= X-Google-Smtp-Source: ABdhPJx31EWK5tF+LMBJ3oGxSWTZDfT1fmQiRJmKhZA0zRDBYCRb6cKfB1Sb7CHi9VbuDVEDPmwMDA== X-Received: by 2002:ac8:7776:: with SMTP id h22mr4998624qtu.325.1616089500685; Thu, 18 Mar 2021 10:45:00 -0700 (PDT) Received: from li-908e0a4c-2250-11b2-a85c-f027e903211b.ibm.com (179-125-249-210.dynamic.desktop.com.br. [179.125.249.210]) by smtp.gmail.com with ESMTPSA id p8sm1940785qtu.8.2021.03.18.10.44.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Mar 2021 10:45:00 -0700 (PDT) From: Leonardo Bras To: Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Leonardo Bras , Alexey Kardashevskiy , Nicolin Chen , Niklas Schnelle Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/1] powerpc/kernel/iommu: Align size for IOMMU_PAGE_SIZE() to save TCEs Date: Thu, 18 Mar 2021 14:44:14 -0300 Message-Id: <20210318174414.684630-1-leobras.c@gmail.com> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently both iommu_alloc_coherent() and iommu_free_coherent() align the desired allocation size to PAGE_SIZE, and gets system pages and IOMMU mappings (TCEs) for that value. When IOMMU_PAGE_SIZE < PAGE_SIZE, this behavior may cause unnecessary TCEs to be created for mapping the whole system page. Example: - PAGE_SIZE = 64k, IOMMU_PAGE_SIZE() = 4k - iommu_alloc_coherent() is called for 128 bytes - 1 system page (64k) is allocated - 16 IOMMU pages (16 x 4k) are allocated (16 TCEs used) It would be enough to use a single TCE for this, so 15 TCEs are wasted in the process. Update iommu_*_coherent() to make sure the size alignment happens only for IOMMU_PAGE_SIZE() before calling iommu_alloc() and iommu_free(). Also, on iommu_range_alloc(), replace ALIGN(n, 1 << tbl->it_page_shift) with IOMMU_PAGE_ALIGN(n, tbl), which is easier to read and does the same. Signed-off-by: Leonardo Bras Reviewed-by: Alexey Kardashevskiy --- arch/powerpc/kernel/iommu.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c index 5b69a6a72a0e..3329ef045805 100644 --- a/arch/powerpc/kernel/iommu.c +++ b/arch/powerpc/kernel/iommu.c @@ -851,6 +851,7 @@ void *iommu_alloc_coherent(struct device *dev, struct iommu_table *tbl, unsigned int order; unsigned int nio_pages, io_order; struct page *page; + size_t size_io = size; size = PAGE_ALIGN(size); order = get_order(size); @@ -877,8 +878,9 @@ void *iommu_alloc_coherent(struct device *dev, struct iommu_table *tbl, memset(ret, 0, size); /* Set up tces to cover the allocated range */ - nio_pages = size >> tbl->it_page_shift; - io_order = get_iommu_order(size, tbl); + size_io = IOMMU_PAGE_ALIGN(size_io, tbl); + nio_pages = size_io >> tbl->it_page_shift; + io_order = get_iommu_order(size_io, tbl); mapping = iommu_alloc(dev, tbl, ret, nio_pages, DMA_BIDIRECTIONAL, mask >> tbl->it_page_shift, io_order, 0); if (mapping == DMA_MAPPING_ERROR) { @@ -893,10 +895,9 @@ void iommu_free_coherent(struct iommu_table *tbl, size_t size, void *vaddr, dma_addr_t dma_handle) { if (tbl) { - unsigned int nio_pages; + size_t size_io = IOMMU_PAGE_ALIGN(size, tbl); + unsigned int nio_pages = size_io >> tbl->it_page_shift; - size = PAGE_ALIGN(size); - nio_pages = size >> tbl->it_page_shift; iommu_free(tbl, dma_handle, nio_pages); size = PAGE_ALIGN(size); free_pages((unsigned long)vaddr, get_order(size)); -- 2.29.2