Re: [PATCH] Add a tracepoint for block request remapping

From: Jun'ichi Nomura
Date: Fri Sep 18 2009 - 10:59:21 EST


Li Zefan wrote:
> Jun'ichi Nomura wrote:
>> Since 2.6.31 now has request-based device-mapper, it's useful to have
>> a tracepoint for request-remapping as well as bio-remapping.
>>
>> This patch adds a tracepoint for request-remapping, trace_block_rq_remap().
>
>> Existing trace_block_remap() is left unchanged but it might be better to
>> rename it to trace_block_bio_remap().
>
> Why not. ;)

OK, I'll add a renaming patch.

>> +static void blk_add_trace_rq_remap(struct request_queue *q,
>> + struct request *rq, dev_t dev,
>> + sector_t from)
>> +{
>> + struct blk_trace *bt = q->blk_trace;
>> + struct blk_io_trace_remap r;
>> +
>> + if (likely(!bt))
>> + return;
>> +
>> + r.device_from = cpu_to_be32(dev);
>> + r.device_to = disk_devt(rq->rq_disk);
>
> cpu_to_be32(dis_devt(...))

Thank you! I'll fix that.

>> + r.sector_from = cpu_to_be64(from);
>> +
>> + __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
>> + rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
>> + sizeof(r), &r);
>> +}

--
Jun'ichi Nomura, NEC Corporation
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