Re: [PATCH 2/2 v2] writeback: Add writeback stats for pages written

[Wu Fengguang <fengguang.wu@intel.com>]

Curt,

> >  The above stats are probably useful. I'm not so convinced about the stats
> > below - it looks like it should be simple enough to get them by enabling
> > some trace points and processing output (or if we are missing some
> > tracepoints, it would be worthwhile to add them).
> 
> For these specifically, I'd agree with you.  In general, though, I
> think that having generally available aggregated stats is really
> useful, in a different way than tracepoints are.

If there comes such useful aggregated stats in future, they may go to
vmstat and/or /debug/bdi/<dev>/stats.

Then we make the writeback stats a simple uniform interface rather
than a hybrid one.

> >
> >>    periodic writeback                      377

The above one can go to the "work" column, "periodic" row of the
writeback stats table :)

I'm in particular interested in the "work" column of the
"try_to_free_pages" row. I also suspect there could be many
short-lived background work, hence there lots of them.

> >>    single inode wait                         0
> >>    writeback_wb wait                         1

Thanks,
Fengguang
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html