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    SubjectRe: [PATCH 8/8] blk-mq: support per-distpatch_queue flush machinery
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    On Wed, Sep 10, 2014 at 2:48 AM, Christoph Hellwig <hch@infradead.org> wrote:
    >> + if (hctx) {
    >> + int cmd_sz = q->tag_set->cmd_size;
    >> + int node = hctx->numa_node;
    >> +
    >> + fq = kzalloc_node(sizeof(*fq), GFP_KERNEL, node);
    >> + if (!fq)
    >> + goto failed;
    >> +
    >> + rq_sz = round_up(rq_sz + cmd_sz, cache_line_size());
    >> + fq->flush_rq = kzalloc_node(rq_sz, GFP_KERNEL, node);
    >> + if (!fq->flush_rq)
    >> + goto rq_failed;
    >> +
    >> + spin_lock_init(&fq->mq_flush_lock);
    >> + } else {
    >> + fq = kzalloc(sizeof(*fq), GFP_KERNEL);
    >> + if (!fq)
    >> + goto failed;
    >> +
    >> + fq->flush_rq = kzalloc(rq_sz, GFP_KERNEL);
    >> + if (!fq->flush_rq)
    >> + goto rq_failed;
    >> + }
    >
    > Seems like this would be a lot cleaner by passing the cmd_size and
    > node_id explicitly. The added benefit would be that we could also
    > pass the node for the blk_init_queue_node() case.

    OK.

    >
    >> +static void __blk_mq_exit_flush(struct request_queue *q,
    >> + unsigned free_end, unsigned int exit_end)
    >> +{
    >> + struct blk_mq_hw_ctx *hctx;
    >> + unsigned int k;
    >> + struct blk_flush_queue *fq;
    >> + struct blk_mq_tag_set *set = q->tag_set;
    >> + unsigned start_idx = set->queue_depth;
    >> +
    >> + queue_for_each_hw_ctx(q, hctx, k) {
    >> + if (k >= free_end)
    >> + break;
    >> +
    >> + fq = hctx->fq;
    >> + if (k < exit_end && set->ops->exit_request)
    >> + set->ops->exit_request(set->driver_data,
    >> + fq->flush_rq, k,
    >> + start_idx + k);
    >> +
    >> + blk_free_flush_queue(fq);
    >> + }
    >
    > Can we merge the mq init/exit case into some existing for each hctx
    > loop in blk-mq?

    I am wondering we can do that because lifetime is totally different
    between flush requests and tag_set requests which are initialized
    before request queue is created.

    Thanks,


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      Last update: 2014-09-10 04:21    [W:2.723 / U:0.116 seconds]
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