Re: [PATCH] blktrace: Use rq->cmd_flags directly in blk_add_trace_rq.

[Jens Axboe <jaxboe@fusionio.com>]

On 2011-03-04 07:15, Tao Ma wrote:
> From: Tao Ma <boyu.mt@taobao.com>
> 
> In blk_add_trace_rq, we only chose the minor 2 bits from
> request's cmd_flags and did some check for discard.
> so most of other flags(e.g, REQ_SYNC) are missing.
> 
> For example, with a sync write after blkparse we get:
>   8,16   1        1     0.001776503  7509  A  WS 1349632 + 1024 <- (8,17) 1347584
>   8,16   1        2     0.001776813  7509  Q  WS 1349632 + 1024 [dd]
>   8,16   1        3     0.001780395  7509  G  WS 1349632 + 1024 [dd]
>   8,16   1        5     0.001783186  7509  I   W 1349632 + 1024 [dd]
>   8,16   1       11     0.001816987  7509  D   W 1349632 + 1024 [dd]
>   8,16   0        2     0.006218192     0  C   W 1349632 + 1024 [0]
> 
> Since now we have integrated the flags of both bio and request,
> it is safe to pass rq->cmd_flags directly to __blk_add_trace.
> 
> With this patch, after a sync write we get:
>   8,16   1        1     0.001776900  5425  A  WS 1189888 + 1024 <- (8,17) 1187840
>   8,16   1        2     0.001777179  5425  Q  WS 1189888 + 1024 [dd]
>   8,16   1        3     0.001780797  5425  G  WS 1189888 + 1024 [dd]
>   8,16   1        5     0.001783402  5425  I  WS 1189888 + 1024 [dd]
>   8,16   1       11     0.001817468  5425  D  WS 1189888 + 1024 [dd]
>   8,16   0        2     0.005640709     0  C  WS 1189888 + 1024 [0]

Thanks, applied!

-- 
Jens Axboe