From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753719AbbAWGgK (ORCPT ); Fri, 23 Jan 2015 01:36:10 -0500 Received: from lgeamrelo02.lge.com ([156.147.1.126]:47575 "EHLO lgeamrelo02.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752027AbbAWGgI (ORCPT ); Fri, 23 Jan 2015 01:36:08 -0500 X-Original-SENDERIP: 10.177.222.153 X-Original-MAILFROM: iamjoonsoo.kim@lge.com Date: Fri, 23 Jan 2015 15:37:10 +0900 From: Joonsoo Kim To: Sasha Levin Cc: linux-kernel@vger.kernel.org, m.szyprowski@samsung.com, akpm@linux-foundation.org, lauraa@codeaurora.org Subject: Re: [PATCH 2/3] mm: cma: allocation trigger Message-ID: <20150123063710.GC809@js1304-P5Q-DELUXE> References: <1421775513-4460-1-git-send-email-sasha.levin@oracle.com> <1421775513-4460-3-git-send-email-sasha.levin@oracle.com> <20150122082628.GH21444@js1304-P5Q-DELUXE> <54C1B679.5030000@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54C1B679.5030000@oracle.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 22, 2015 at 09:48:25PM -0500, Sasha Levin wrote: > On 01/22/2015 03:26 AM, Joonsoo Kim wrote: > > On Tue, Jan 20, 2015 at 12:38:32PM -0500, Sasha Levin wrote: > >> Provides a userspace interface to trigger a CMA allocation. > >> > >> Usage: > >> > >> echo [pages] > alloc > >> > >> This would provide testing/fuzzing access to the CMA allocation paths. > >> > >> Signed-off-by: Sasha Levin > >> --- > >> mm/cma_debug.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > >> 1 file changed, 58 insertions(+) > >> > >> diff --git a/mm/cma_debug.c b/mm/cma_debug.c > >> index 3a25413..eda0a41 100644 > >> --- a/mm/cma_debug.c > >> +++ b/mm/cma_debug.c > >> @@ -7,9 +7,22 @@ > >> > >> #include > >> #include > >> +#include > >> +#include > >> +#include > >> +#include > >> > >> #include "cma.h" > >> > >> +struct cma_mem { > >> + struct hlist_node node; > >> + struct page *p; > >> + unsigned long n; > >> +}; > >> + > >> +static HLIST_HEAD(cma_mem_head); > >> +static DEFINE_SPINLOCK(cma_mem_head_lock); > >> + > >> static struct dentry *cma_debugfs_root; > >> > >> static int cma_debugfs_get(void *data, u64 *val) > >> @@ -44,6 +57,48 @@ static void cma_debugfs_add_one(struct cma *cma, int idx) > >> debugfs_create_u32_array("bitmap", S_IRUGO, tmp, (u32*)cma->bitmap, u32s); > >> } > >> > >> +static void cma_add_to_cma_mem_list(struct cma_mem *mem) > >> +{ > >> + spin_lock(&cma_mem_head_lock); > >> + hlist_add_head(&mem->node, &cma_mem_head); > >> + spin_unlock(&cma_mem_head_lock); > >> +} > >> + > >> +static int cma_alloc_mem(int count) > >> +{ > >> + struct cma_mem *mem; > >> + struct page *p; > >> + > >> + mem = kzalloc(sizeof(*mem), GFP_KERNEL); > >> + if (!mem) > >> + return -ENOMEM; > >> + > >> + p = cma_alloc(dma_contiguous_default_area, count, CONFIG_CMA_ALIGNMENT); > >> + if (!p) { > >> + pr_info("CMA: Allocation failed.\n"); > >> + kfree(mem); > >> + return -ENOMEM; > >> + } > > > > Hello, > > > > I'm glad to see this patchset. I had similar one privately. :) > > Without this kind of facility, testing CMA is really hard. > > > > Anyway, dma_contiguous_default_area is defined only in CONFIG_DMA_CMA. > > So, it would cause build break. > > > > And, I think that it is better for this tester to have an ability to > > allocate pages on specific CMA reserved region. It could be easily > > achieved by moving 'alloc' registration to cma_debugfs_add_one(). Is > > there any reason not to do that? > > Agreed, that would make more sense. > > >> + > >> + pr_info("CMA: Allocated %d pages at %p\n", count, p); > > > > I don't think this output is needed. If CONFIG_CMA_DEBUG is enabled, > > cma_alloc() print similar output. > > I didn't see any other output (and I have CONFIG_CMA_DEBUG set), which > is why I've added this pr_info(). If you raise up your loglevel, you can see it. That message is printed through pr_debug(). Thanks.