From: Ming Lei <ming.lei@canonical.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux SCSI List <linux-scsi@vger.kernel.org>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 5/8] block: introduce blk_flush_queue to drive flush machinery
Date: Wed, 10 Sep 2014 09:23:27 +0800 [thread overview]
Message-ID: <CACVXFVNjQyS6HzQy418jKGqjBr+waTx-gMrDnE9uhvfzUEJMaA@mail.gmail.com> (raw)
In-Reply-To: <20140909184331.GE16750@infradead.org>
On Wed, Sep 10, 2014 at 2:43 AM, Christoph Hellwig <hch@infradead.org> wrote:
> On Tue, Sep 09, 2014 at 09:05:46PM +0800, Ming Lei wrote:
>> This patch introduces 'struct blk_flush_queue' and puts all
>> flush machinery related stuff into this strcuture, so that
>
> s/stuff/fields/
> s/strcuture/structure/
>
> Looks good, but a few more nitpicks below.
>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
>
>> +int blk_init_flush(struct request_queue *q)
>> +{
>> + int ret;
>> + struct blk_flush_queue *fq = kzalloc(sizeof(*fq), GFP_KERNEL);
>>
>> + if (!fq)
>> return -ENOMEM;
>>
>> + q->fq = fq;
>
> I think it would be cleaner to return the flush data structure and
> assign it in the caller.
OK, and most of this part is transitional.
>
>> + INIT_LIST_HEAD(&fq->flush_queue[0]);
>> + INIT_LIST_HEAD(&fq->flush_queue[1]);
>> + INIT_LIST_HEAD(&fq->flush_data_in_flight);
>> +
>> + if (q->mq_ops) {
>> + ret = blk_mq_init_flush(q);
>
> I think we can just remove blk_mq_init_flush now that it's only
> called in blk-flush.c anyway.
blk_mq_init_flush() will become bigger in following patch.
>> void blk_exit_flush(struct request_queue *q)
>> {
>> + if (q->mq_ops)
>> + blk_mq_exit_flush(q);
>> + else {
>> + struct blk_flush_queue *fq = blk_get_flush_queue(q);
>> + kfree(fq->flush_rq);
>> + kfree(fq);
>> + }
>
> Similarly I would pass the flush structure here.
OK.
>
>> +struct blk_flush_queue {
>> + unsigned int flush_queue_delayed:1;
>> + unsigned int flush_pending_idx:1;
>> + unsigned int flush_running_idx:1;
>> + unsigned long flush_pending_since;
>> + struct list_head flush_queue[2];
>> + struct list_head flush_data_in_flight;
>> + struct request *flush_rq;
>> + spinlock_t mq_flush_lock;
>> +};
>
> As this isn't really a queue I would call it blk_flush_data.
It is sort of a queue since there is a double buffer flush queue.
>
>> +static inline struct blk_flush_queue *blk_get_flush_queue(
>> + struct request_queue *q)
>> +{
>> + return q->fq;
>> +}
>
> I don't think there is a need for this helper.
No, the helper can simplify the following patch a lot since
the flush queue data is always obtained from this helper in both
legacy and mq case, which will take per-hw_queue flush queue.
Thanks,
next prev parent reply other threads:[~2014-09-10 1:23 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-09 13:05 [PATCH 0/8] block: per-distpatch_queue flush machinery Ming Lei
2014-09-09 13:05 ` [PATCH 1/8] blk-mq: allocate flush_rq in blk_mq_init_flush() Ming Lei
2014-09-09 18:35 ` Christoph Hellwig
2014-09-09 13:05 ` [PATCH 2/8] block: introduce blk_init_flush and its pair Ming Lei
2014-09-09 18:36 ` Christoph Hellwig
2014-09-09 13:05 ` [PATCH 3/8] block: move flush initialized stuff to blk_flush_init Ming Lei
2014-09-09 18:37 ` Christoph Hellwig
2014-09-09 13:05 ` [PATCH 4/8] block: avoid to use q->flush_rq directly Ming Lei
2014-09-09 18:38 ` Christoph Hellwig
2014-09-09 13:05 ` [PATCH 5/8] block: introduce blk_flush_queue to drive flush machinery Ming Lei
2014-09-09 18:43 ` Christoph Hellwig
2014-09-09 18:55 ` Jens Axboe
2014-09-10 1:25 ` Ming Lei
2014-09-10 1:23 ` Ming Lei [this message]
2014-09-09 13:05 ` [PATCH 6/8] block: flush: avoid to figure out flush queue unnecessarily Ming Lei
2014-09-09 18:44 ` Christoph Hellwig
2014-09-09 13:05 ` [PATCH 7/8] block: introduce 'blk_mq_ctx' parameter to blk_get_flush_queue Ming Lei
2014-09-09 13:05 ` [PATCH 8/8] blk-mq: support per-distpatch_queue flush machinery Ming Lei
2014-09-09 18:48 ` Christoph Hellwig
2014-09-10 1:40 ` Ming Lei
2014-09-10 19:02 ` Christoph Hellwig
2014-09-10 23:53 ` Ming Lei
2014-09-09 15:20 ` [PATCH 0/8] block: " Christoph Hellwig
2014-09-09 15:38 ` Ming Lei
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