Subject: Re: [PATCH] swiotlb: suppress warning when __GFP_NOWARN is set.
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        linux-kernel@vger.kernel.org
References: <20171219143255.2262-1-christian.koenig@amd.com>
 <BA0FE1EC-F17E-4AA3-80BA-10357E8C8B95@oracle.com>
Cc: Mike Galbraith <efault@gmx.de>
From: =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>
Message-ID: <58a552e3-b730-2417-b16c-adde61812e79@amd.com>
Date: Tue, 19 Dec 2017 19:06:43 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.5.0
MIME-Version: 1.0
In-Reply-To: <BA0FE1EC-F17E-4AA3-80BA-10357E8C8B95@oracle.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
Content-Language: en-US
SpamDiagnosticOutput: 1:99
SpamDiagnosticMetadata: NSPM
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Dec 2017 18:06:52.9464 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: d8ca3c43-2404-4e54-0a64-08d5470b491f
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR12MB1306
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 1307
Lines: 45

Am 19.12.2017 um 15:52 schrieb Konrad Rzeszutek Wilk:
> On December 19, 2017 9:32:55 AM EST, "Christian König" <ckoenig.leichtzumerken@gmail.com> wrote:
>> TTM tries to allocate coherent memory in chunks of 2MB first to improve
>> TLB efficiency and falls back to allocating 4K pages if that fails.
>>
>> Suppress the warning when the 2MB allocations fails since there is a
>> valid fall back path.
>>
>> Signed-off-by: Christian König <christian.koenig@amd.com>
> Is there an Reported by or such needed?

Sorry my fault not to include that.

Reported-by: Mike Galbraith <efault@gmx.de>.

>> ---
>> lib/swiotlb.c | 8 +++++---
>> 1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/lib/swiotlb.c b/lib/swiotlb.c
>> index cea19aaf303c..63a44fb29ce6 100644
>> --- a/lib/swiotlb.c
>> +++ b/lib/swiotlb.c
>> @@ -769,9 +769,11 @@ swiotlb_alloc_coherent(struct device *hwdev,
>> size_t size,
>> 	return ret;
>>
>> err_warn:
>> -	pr_warn("swiotlb: coherent allocation failed for device %s
>> size=%zu\n",
>> -		dev_name(hwdev), size);
>> -	dump_stack();
>> +	if (!(flags & __GFP_NOWARN)) {
>> +		pr_warn("swiotlb: coherent allocation failed for device %s
>> size=%zu\n",
>> +			dev_name(hwdev), size);
>> +		dump_stack();
>> +	}
> Ok, let me queue it up.

Thanks,
Christian.

>> 	return NULL;
>> }