Re: [PATCH 09/13] lightnvm: pblk: Kick writer for flush requests

Hans Holmberg
2019-03-04T09:39:59Z

On Mon, Mar 4, 2019 at 9:08 AM Javier González <javier@javigon.com> wrote:
>
>
> > On 27 Feb 2019, at 18.14, Igor Konopko <igor.j.konopko@intel.com> wrote:
> >
> > In case when there is no enough sector available in rwb
> > and there is flush request send we should kick write thread
> > which is not a case in current implementation. This patch
> > fixes that issue.
> >
> > Signed-off-by: Igor Konopko <igor.j.konopko@intel.com>
> > ---
> > drivers/lightnvm/pblk-core.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
> > index 78b1eea4ab67..f48f2e77f770 100644
> > --- a/drivers/lightnvm/pblk-core.c
> > +++ b/drivers/lightnvm/pblk-core.c
> > @@ -375,8 +375,9 @@ void pblk_write_timer_fn(struct timer_list *t)
> > void pblk_write_should_kick(struct pblk *pblk)
> > {
> > unsigned int secs_avail = pblk_rb_read_count(&pblk->rwb);
> > + unsigned int secs_to_flush = pblk_rb_flush_point_count(&pblk->rwb);
> >
> > - if (secs_avail >= pblk->min_write_pgs_data)
> > + if (secs_avail >= pblk->min_write_pgs_data || secs_to_flush)
> > pblk_write_kick(pblk);
> > }
> >
> > --
> > 2.17.1
>
> We already kick the write thread in case of REQ_PREFLUSH in
> pblk_write_cache(), so no need to kick again.

Yeah, I thought i fixed this issue in:

cc9c9a00b10e ("lightnvm: pblk: kick writer on new flush points")

That commit brought down the test time of some of the xfs sync tests
with a factor of 20 or so.

Igor: Have you seen any case of delayed syncs?

>
> Javier