----- Original Message -----
> From: "Coly Li" <colyli@xxxxxxx>
> To: "Xiao Ni" <xni@xxxxxxxxxx>, linux-raid@xxxxxxxxxxxxxxx
> Cc: shli@xxxxxxxxxx, neilb@xxxxxxxx, ncroxon@xxxxxxxxxx
> Sent: Wednesday, April 26, 2017 9:55:30 PM
> Subject: Re: [MD PATCH 1/1] Use a new variable to count flighting sync requests
>
> On 2017/4/26 下午9:32, Xiao Ni wrote:
> > In new barrier codes, raise_barrier waits if conf->nr_pending[idx] is not
> > zero.
> > After all the conditions are true, the resync request can go on be handled.
> > But
> > it adds conf->nr_pending[idx] again. The next resync request hit the same
> > bucket
> > idx need to wait the resync request which is submitted before. The
> > performance
> > of resync/recovery is degraded.
> > So we should use a new variable to count sync requests which are in flight.
> >
> > Suggested-by: Shaohua Li <shli@xxxxxxxxxx>
> > Suggested-by: Coly Li <colyli@xxxxxxx>
> > Signed-off-by: Xiao Ni <xni@xxxxxxxxxx>
>
> Hi Xiao,
>
> The patch looks good to me. But I do have interest to have a look on the
> performance number, does this patch help to improve resync throughput ?
> Thanks.
>
> Coly Li
Hi Coly
The server which I did test is down now. I'll give the test result ASAP.
Regards
Xiao
>
> > ---
> > drivers/md/raid1.c | 14 +++++++++++---
> > drivers/md/raid1.h | 1 +
> > 2 files changed, 12 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> > index a34f587..3c304ef 100644
> > --- a/drivers/md/raid1.c
> > +++ b/drivers/md/raid1.c
> > @@ -869,7 +869,7 @@ static void raise_barrier(struct r1conf *conf, sector_t
> > sector_nr)
> > atomic_read(&conf->barrier[idx]) < RESYNC_DEPTH,
> > conf->resync_lock);
> >
> > - atomic_inc(&conf->nr_pending[idx]);
> > + atomic_inc(&conf->nr_sync_pending[idx]);
> > spin_unlock_irq(&conf->resync_lock);
> > }
> >
> > @@ -880,7 +880,7 @@ static void lower_barrier(struct r1conf *conf, sector_t
> > sector_nr)
> > BUG_ON(atomic_read(&conf->barrier[idx]) <= 0);
> >
> > atomic_dec(&conf->barrier[idx]);
> > - atomic_dec(&conf->nr_pending[idx]);
> > + atomic_dec(&conf->nr_sync_pending[idx]);
> > wake_up(&conf->wait_barrier);
> > }
> >
> > @@ -1018,7 +1018,8 @@ static int get_unqueued_pending(struct r1conf *conf)
> > int idx, ret;
> >
> > for (ret = 0, idx = 0; idx < BARRIER_BUCKETS_NR; idx++)
> > - ret += atomic_read(&conf->nr_pending[idx]) -
> > + ret += atomic_read(&conf->nr_pending[idx]) +
> > + atomic_read(&conf->nr_sync_pending[idx]) -
> > atomic_read(&conf->nr_queued[idx]);
> >
> > return ret;
> > @@ -3024,6 +3025,11 @@ static struct r1conf *setup_conf(struct mddev
> > *mddev)
> > if (!conf->nr_pending)
> > goto abort;
> >
> > + conf->nr_sync_pending = kcalloc(BARRIER_BUCKETS_NR,
> > + sizeof(atomic_t), GFP_KERNEL);
> > + if (!conf->nr_sync_pending)
> > + goto abort;
> > +
> > conf->nr_waiting = kcalloc(BARRIER_BUCKETS_NR,
> > sizeof(atomic_t), GFP_KERNEL);
> > if (!conf->nr_waiting)
> > @@ -3136,6 +3142,7 @@ static struct r1conf *setup_conf(struct mddev *mddev)
> > kfree(conf->mirrors);
> > safe_put_page(conf->tmppage);
> > kfree(conf->poolinfo);
> > + kfree(conf->nr_sync_pending);
> > kfree(conf->nr_pending);
> > kfree(conf->nr_waiting);
> > kfree(conf->nr_queued);
> > @@ -3241,6 +3248,7 @@ static void raid1_free(struct mddev *mddev, void
> > *priv)
> > kfree(conf->mirrors);
> > safe_put_page(conf->tmppage);
> > kfree(conf->poolinfo);
> > + kfree(conf->nr_sync_pending);
> > kfree(conf->nr_pending);
> > kfree(conf->nr_waiting);
> > kfree(conf->nr_queued);
> > diff --git a/drivers/md/raid1.h b/drivers/md/raid1.h
> > index dd22a37..a3580ee 100644
> > --- a/drivers/md/raid1.h
> > +++ b/drivers/md/raid1.h
> > @@ -85,6 +85,7 @@ struct r1conf {
> > wait_queue_head_t wait_barrier;
> > spinlock_t resync_lock;
> > atomic_t *nr_pending;
> > + atomic_t *nr_sync_pending;
> > atomic_t *nr_waiting;
> > atomic_t *nr_queued;
> > atomic_t *barrier;
> >
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
