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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 8D923C43381 for ; Wed, 27 Mar 2019 08:08:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5934B2082F for ; Wed, 27 Mar 2019 08:08:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732007AbfC0IIb (ORCPT ); Wed, 27 Mar 2019 04:08:31 -0400 Received: from verein.lst.de ([213.95.11.211]:40345 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725763AbfC0IIb (ORCPT ); Wed, 27 Mar 2019 04:08:31 -0400 Received: by newverein.lst.de (Postfix, from userid 2407) id 92A5A68B05; Wed, 27 Mar 2019 09:08:21 +0100 (CET) Date: Wed, 27 Mar 2019 09:08:21 +0100 From: Christoph Hellwig To: Nicolin Chen Cc: hch@lst.de, robin.murphy@arm.com, vdumpa@nvidia.com, linux@armlinux.org.uk, catalin.marinas@arm.com, will.deacon@arm.com, joro@8bytes.org, m.szyprowski@samsung.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, tony@atomide.com Subject: Re: [PATCH v2 RFC/RFT 0/5] Save single pages from CMA area Message-ID: <20190327080821.GB20336@lst.de> References: <20190326230131.16275-1-nicoleotsuka@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190326230131.16275-1-nicoleotsuka@gmail.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 26, 2019 at 04:01:26PM -0700, Nicolin Chen wrote: > This series of patches try to save single pages from CMA area bypassing > all CMA single page alloctions and allocating normal pages instead, as > all addresses within one single page are contiguous. > > We had once applied the PATCH-5 but reverted it as actually not all the > callers handled the fallback allocations. Per Robin's suggestion, let's > stuff alloc_pages()/free_page() fallbacks to those callers before having > PATCH-5. Given the problems this has caused so far I'd like to see a good explanation of why this optimization is so important that all the churn is even worth it..