On Jun 13, 2017, at 11:15 AM, Jens Axboe <axboe@xxxxxxxxx> wrote:
>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> ---
> include/linux/blk_types.h | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
> index 1940876a7fa7..16c4e657807f 100644
> --- a/include/linux/blk_types.h
> +++ b/include/linux/blk_types.h
> @@ -314,6 +314,19 @@ struct blk_rq_stat {
> u64 batch;
> };
>
> +/*
> + * Data life time definitions for writes. These are relative within a
> + * given device, no absolute meaning is attached to them.
> + */
> +enum {
> + WRITE_LIFE_UNKNOWN = 0,
> + WRITE_LIFE_SHORT,
> + WRITE_LIFE_MEDIUM,
> + WRITE_LIFE_LONG,
> + WRITE_LIFE_EXTREME,
> + WRITE_LIFE_NR,
> +};
With the exception of these enums, there is actually enough space in the
various structures to pass at least a 4-bit stream ID through the whole
stack (actually, a full 32-bit stream ID, except for the debugfs stats).
I'm not necessarily against having some pre-defined meanings for these
values, but with a few trivial changes to the code it would be possible
to make this functionality much more flexible.
Comments inline on each of the patches where this matters.
Cheers, Andreas
> +
> static inline void bio_set_streamid(struct bio *bio, unsigned int stream)
> {
> bio->bi_stream = stream;
> --
> 2.7.4
>
Cheers, Andreas
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