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From: John Garry <john.garry@huawei.com>
To: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>, <linux-block@vger.kernel.org>,
	Bart Van Assche <bvanassche@acm.org>,
	Hannes Reinecke <hare@suse.com>, Christoph Hellwig <hch@lst.de>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH V9 00/11] blk-mq: improvement CPU hotplug
Date: Mon, 4 May 2020 10:57:19 +0100	[thread overview]
Message-ID: <6e4c4382-c52b-14ac-8538-71e683dce47e@huawei.com> (raw)
In-Reply-To: <4892e8d0-0a4b-2f35-130c-eae23d578549@huawei.com>

On 04/05/2020 10:07, John Garry wrote:
> On 04/05/2020 09:38, Ming Lei wrote:
>>> [67.602937]  refcount_warn_saturate+0x6c/0x13c
>>> [67.607369]  aio_complete_rw+0x350/0x384
>>> [67.611279]  blkdev_bio_end_io+0xc4/0x12c
>>> [67.615276]  bio_endio+0x104/0x130
>>> [67.618665]  blk_update_request+0x98/0x37c
>>> [67.622748]  blk_mq_end_request+0x24/0x138
>>> [67.626831]  blk_mq_resubmit_end_rq+0x40/0x58
>>> [67.631174]  __blk_mq_end_request+0xb0/0x10c
>>> [67.635432]  scsi_end_request+0xdc/0x20c
>> Looks an old issue, I believe the following patch can fix the issue:
>>
>> diff --git a/block/blk-mq.c b/block/blk-mq.c
>> index 12dee4ecd5cc..3fc79d4b2fe0 100644
>> --- a/block/blk-mq.c
>> +++ b/block/blk-mq.c
>> @@ -2415,6 +2415,10 @@ static void blk_mq_resubmit_rq(struct request *rq)
>>       nrq->bio = rq->bio;
>>       nrq->biotail = rq->biotail;
>> +    /* Now all bios ownership is transfered to 'nrq' */
>> +    rq->bio = rq->biotail = NULL;
>> +    rq->__data_len = 0;
>> +
>>       if (blk_insert_cloned_request(nrq->q, nrq) != BLK_STS_OK)
>>           blk_mq_request_bypass_insert(nrq, false, true);
>>   }
> 
> ok, looks much better.
> 
> I'll test this a bit more now.

looks pretty solid now. I assume we'll see a v10, so please add:

Tested-by: John Garry <john.garry@huawei.com>

> 
> cheers
> 
> .


      reply	other threads:[~2020-05-04  9:58 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-02 23:54 [PATCH V9 00/11] blk-mq: improvement CPU hotplug Ming Lei
2020-05-02 23:54 ` [PATCH V9 01/11] block: clone nr_integrity_segments and write_hint in blk_rq_prep_clone Ming Lei
2020-05-02 23:54 ` [PATCH V9 02/11] block: add helper for copying request Ming Lei
2020-05-02 23:54 ` [PATCH V9 03/11] blk-mq: mark blk_mq_get_driver_tag as static Ming Lei
2020-05-02 23:54 ` [PATCH V9 04/11] blk-mq: assign rq->tag in blk_mq_get_driver_tag Ming Lei
2020-05-02 23:54 ` [PATCH V9 05/11] blk-mq: support rq filter callback when iterating rqs Ming Lei
2020-05-04  7:04   ` Hannes Reinecke
2020-05-02 23:54 ` [PATCH V9 06/11] blk-mq: prepare for draining IO when hctx's all CPUs are offline Ming Lei
2020-05-02 23:54 ` [PATCH V9 07/11] blk-mq: stop to handle IO and drain IO before hctx becomes inactive Ming Lei
2020-05-02 23:54 ` [PATCH V9 08/11] block: add blk_end_flush_machinery Ming Lei
2020-05-02 23:54 ` [PATCH V9 09/11] blk-mq: add blk_mq_hctx_handle_dead_cpu for handling cpu dead Ming Lei
2020-05-02 23:54 ` [PATCH V9 10/11] blk-mq: re-submit IO in case that hctx is inactive Ming Lei
2020-05-02 23:54 ` [PATCH V9 11/11] block: deactivate hctx when the hctx is actually inactive Ming Lei
2020-05-04  8:14 ` [PATCH V9 00/11] blk-mq: improvement CPU hotplug John Garry
2020-05-04  8:38   ` Ming Lei
2020-05-04  9:07     ` John Garry
2020-05-04  9:57       ` John Garry [this message]

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