Re: [PATCH] blktrace: correct remap names

[Ingo Molnar]

* Alan D. Brunelle <Alan.Brunelle@xxxxxx> wrote:

> Ingo Molnar wrote:
> > * Li Zefan <lizf@xxxxxxxxxxxxxx> wrote:
> > 
> >>> Subject: [PATCH] blktrace: correct remap names
> >>>
> >>> This attempts to clarify names utilized during block I/O remap operations
> >>> (partition, volume manager). It correctly matches up the /from/ information for both device & sector. This takes in the concept from osaki Motohiro and extends it to include better naming for the "device_from" field.
> >>>
> >> I also noticed this..
> >>
> >>> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
> >>> Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
> >>> Cc: Jens Axboe <jens.axboe@xxxxxxxxxx>
> >>> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> >>> Signed-off-by: Alan D. Brunelle <alan.brunelle@xxxxxx>
> >>> ---
> >>>  include/linux/blktrace_api.h |    4 ++--
> >>>  include/trace/block.h        |    4 ++--
> >>>  kernel/trace/blktrace.c      |   21 +++++++++++----------
> >>>  3 files changed, 15 insertions(+), 14 deletions(-)
> >>>
> >>> diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
> >>> index d960889..da1a14e 100644
> >>> --- a/include/linux/blktrace_api.h
> >>> +++ b/include/linux/blktrace_api.h
> >>> @@ -116,9 +116,9 @@ struct blk_io_trace {
> >>>   * The remap event
> >>>   */
> >>>  struct blk_io_trace_remap {
> >>> -	__be32 device;
> >>>  	__be32 device_from;
> >>> -	__be64 sector;
> >>> +	__be32 device_to;
> >>> +	__be64 sector_from;
> >>>  };
> >>>  
> >> If we are really fine with this change, then:
> >>
> >> Reviewed-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
> > 
> > is it acceptable to break the sector output ordering of all past 
> > blktrace+blkparse binaries, as far as remap events go?
> > 
> > 	Ingo
> 
> The binary order of data sent remains the same: the field names 
> for the structure & parameters passed around were 
> wrong^Wmisleading (as was pointed out previously by Kosaki 
> Motoiro). I've tested this and the blkparse output remains 
> identical (both with the previous version of blktrace/blkparse & 
> with a posted patch to blkparse which also fixes the field names 
> of blk_io_trace_remap). The testing included permutations of 
> (old/new) kernel traces & (old/new) blkparse. They all resulted in 
> the same blkparse output.

Ah, ok - my worry was baseless then - thanks! I'll queue them up in 
tip/tracing/blktrace.

	Ingo
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