From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753637AbcEIXug (ORCPT ); Mon, 9 May 2016 19:50:36 -0400 Received: from mail-pa0-f54.google.com ([209.85.220.54]:33861 "EHLO mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753163AbcEIXuf (ORCPT ); Mon, 9 May 2016 19:50:35 -0400 Subject: Re: [RESEND PATCH] ION: Sys_heap: Add cached pool to spead up cached buffer alloc To: Chen Feng , saberlily.xia@hisilicon.com, gregkh@linuxfoundation.org, arve@android.com, riandrews@android.com, paul.gortmaker@windriver.com, bmarsh94@gmail.com, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org References: <1462783054-36053-1-git-send-email-puck.chen@hisilicon.com> Cc: xuyiping@hisilicon.com, suzhuangluan@hisilicon.com, dan.zhao@hisilicon.com, linuxarm@huawei.com, puck.chen@foxmail.com From: Laura Abbott Message-ID: <5aef4164-1055-4fca-51ea-3327b9febc10@redhat.com> Date: Mon, 9 May 2016 16:50:31 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.0 MIME-Version: 1.0 In-Reply-To: <1462783054-36053-1-git-send-email-puck.chen@hisilicon.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/09/2016 01:37 AM, Chen Feng wrote: > Add ion cached pool in system heap. > > Signed-off-by: Chen Feng > Signed-off-by: Xia Qing > Reviewed-by: Fu Jun > --- > drivers/staging/android/ion/ion_system_heap.c | 145 +++++++++++++++++--------- > 1 file changed, 95 insertions(+), 50 deletions(-) > > diff --git a/drivers/staging/android/ion/ion_system_heap.c b/drivers/staging/android/ion/ion_system_heap.c > index b69dfc7..c633252 100644 > --- a/drivers/staging/android/ion/ion_system_heap.c > +++ b/drivers/staging/android/ion/ion_system_heap.c > @@ -49,7 +49,8 @@ static inline unsigned int order_to_size(int order) > > struct ion_system_heap { > struct ion_heap heap; > - struct ion_page_pool *pools[0]; > + struct ion_page_pool *uncached_pools[0]; > + struct ion_page_pool *cached_pools[0]; > }; > > static struct page *alloc_buffer_page(struct ion_system_heap *heap, > @@ -57,39 +58,36 @@ static struct page *alloc_buffer_page(struct ion_system_heap *heap, > unsigned long order) > { > bool cached = ion_buffer_cached(buffer); > - struct ion_page_pool *pool = heap->pools[order_to_index(order)]; > + struct ion_page_pool *pool; > struct page *page; > > - if (!cached) { > - page = ion_page_pool_alloc(pool); > - } else { > - gfp_t gfp_flags = low_order_gfp_flags; > - > - if (order > 4) > - gfp_flags = high_order_gfp_flags; > - page = alloc_pages(gfp_flags | __GFP_COMP, order); > - if (!page) > - return NULL; > - ion_pages_sync_for_device(NULL, page, PAGE_SIZE << order, > - DMA_BIDIRECTIONAL); > - } > + if (!cached) > + pool = heap->uncached_pools[order_to_index(order)]; > + else > + pool = heap->cached_pools[order_to_index(order)]; > > + page = ion_page_pool_alloc(pool); > return page; > } > This is a change in behavior. The page is no longer guaranteed to be synced in the cache. If the page came from the pool (not just freshly allocated) the cache state is unknown. Do you have a good explanation why we no longer need to do the cache flush here on every allocation? Thanks, Laura