Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH] block/bfq: fix ifdef for CONFIG_BFQ_GROUP_IOSCHED=y
To:     =?UTF-8?Q?Holger_Hoffst=c3=a4tte?= <holger@applied-asynchrony.com>,
        Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
        linux-block@vger.kernel.org,
        Paolo Valente <paolo.valente@linaro.org>,
        linux-kernel@vger.kernel.org
References: <155386807826.3190.16175453392005064129.stgit@buzz>
 <c40b8d4a-c504-fdf4-0b96-64aaeb167435@applied-asynchrony.com>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <5234a971-2b6a-47b1-0071-8f3bd07d9fc3@kernel.dk>
Date:   Fri, 29 Mar 2019 09:58:22 -0600
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.6.1
MIME-Version: 1.0
In-Reply-To: <c40b8d4a-c504-fdf4-0b96-64aaeb167435@applied-asynchrony.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 3/29/19 9:56 AM, Holger Hoffstätte wrote:
> On 3/29/19 3:01 PM, Konstantin Khlebnikov wrote:
>> Replace BFQ_GROUP_IOSCHED_ENABLED with CONFIG_BFQ_GROUP_IOSCHED.
>> Code under these ifdefs never worked, something might be broken.
>>
>> Fixes: 0471559c2fbd ("block, bfq: add/remove entity weights correctly")
>> Fixes: 73d58118498b ("block, bfq: consider also ioprio classes in symmetry detection")
>> Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
>> ---
>>   block/bfq-iosched.c |    2 +-
>>   block/bfq-wf2q.c    |    2 +-
>>   2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
>> index 4c592496a16a..fac188dd78fa 100644
>> --- a/block/bfq-iosched.c
>> +++ b/block/bfq-iosched.c
>> @@ -674,7 +674,7 @@ static bool bfq_symmetric_scenario(struct bfq_data *bfqd)
>>   	 * at least two nodes.
>>   	 */
>>   	return !(varied_queue_weights || multiple_classes_busy
>> -#ifdef BFQ_GROUP_IOSCHED_ENABLED
>> +#ifdef CONFIG_BFQ_GROUP_IOSCHED
>>   	       || bfqd->num_groups_with_pending_reqs > 0
>>   #endif
>>   		);
>> diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c
>> index 63311d1ff1ed..a11bef75483d 100644
>> --- a/block/bfq-wf2q.c
>> +++ b/block/bfq-wf2q.c
>> @@ -1012,7 +1012,7 @@ static void __bfq_activate_entity(struct bfq_entity *entity,
>>   		entity->on_st = true;
>>   	}
>>   
>> -#ifdef BFQ_GROUP_IOSCHED_ENABLED
>> +#ifdef CONFIG_BFQ_GROUP_IOSCHED
>>   	if (!bfq_entity_to_bfqq(entity)) { /* bfq_group */
>>   		struct bfq_group *bfqg =
>>   			container_of(entity, struct bfq_group, entity);
>>
>>
> 
> Good catch! I run without group scheduling and therefore didn't notice these
> stray defines earlier. For 5.1 it should merge cleanly; adding this on top of
> the pending 5.2 BFQ patches required a small context fixup in hunk #1 due to
> "block, bfq: do not idle for lowest-weight queues".

I'm hesitant to apply this, since the group scheduling stuff has obviously never
been tested.

Hence it should go through some actual testing first, which means it's a 5.2
candidate, not 5.1.

-- 
Jens Axboe