Re: [PATCH] writeback: expose cgroup info in trace_writeback_pages_written()

[Yafang Shao <laoar.shao@gmail.com>]

On Tue, Mar 19, 2019 at 6:40 PM Jan Kara <jack@suse.cz> wrote:
>
> On Sat 23-02-19 21:35:49, Yafang Shao wrote:
> > With cgroup v2 writeback, we can know these pages are written from which
> > cgroup.
> > So expose the cgroup_ino for better tracking.
> >
> > Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
>
> Fine by me. You can add:
>
> Acked-by: Jan Kara <jack@suse.cz>
>

Thanks for your review :-)

>
> > ---
> >  fs/fs-writeback.c                | 4 ++--
> >  include/trace/events/writeback.h | 9 ++++++---
> >  2 files changed, 8 insertions(+), 5 deletions(-)
> >
> > diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> > index 36855c1..e98a33e 100644
> > --- a/fs/fs-writeback.c
> > +++ b/fs/fs-writeback.c
> > @@ -1973,7 +1973,7 @@ void wb_workfn(struct work_struct *work)
> >                */
> >               do {
> >                       pages_written = wb_do_writeback(wb);
> > -                     trace_writeback_pages_written(pages_written);
> > +                     trace_writeback_pages_written(wb, pages_written);
> >               } while (!list_empty(&wb->work_list));
> >       } else {
> >               /*
> > @@ -1983,7 +1983,7 @@ void wb_workfn(struct work_struct *work)
> >                */
> >               pages_written = writeback_inodes_wb(wb, 1024,
> >                                                   WB_REASON_FORKER_THREAD);
> > -             trace_writeback_pages_written(pages_written);
> > +             trace_writeback_pages_written(wb, pages_written);
> >       }
> >
> >       if (!list_empty(&wb->work_list))
> > diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
> > index 32db72c..a806713 100644
> > --- a/include/trace/events/writeback.h
> > +++ b/include/trace/events/writeback.h
> > @@ -255,15 +255,18 @@ static inline unsigned int __trace_wbc_assign_cgroup(struct writeback_control *w
> >  DEFINE_WRITEBACK_WORK_EVENT(writeback_wait);
> >
> >  TRACE_EVENT(writeback_pages_written,
> > -     TP_PROTO(long pages_written),
> > -     TP_ARGS(pages_written),
> > +     TP_PROTO(struct bdi_writeback *wb, long pages_written),
> > +     TP_ARGS(wb, pages_written),
> >       TP_STRUCT__entry(
> >               __field(long,           pages)
> > +             __field(unsigned int,   cgroup_ino)
> >       ),
> >       TP_fast_assign(
> >               __entry->pages          = pages_written;
> > +             __entry->cgroup_ino     = __trace_wb_assign_cgroup(wb);
> >       ),
> > -     TP_printk("%ld", __entry->pages)
> > +     TP_printk("pages=%ld cgroup_ino=%u",
> > +                __entry->pages, __entry->cgroup_ino)
> >  );
> >
> >  DECLARE_EVENT_CLASS(writeback_class,
> > --
> > 1.8.3.1
> >
> --
> Jan Kara <jack@suse.com>
> SUSE Labs, CR