Re: One patch just review the code

[NeilBrown <neilb@suse.de>]

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On Thu, 7 Aug 2014 06:06:19 -0400 (EDT) Xiao Ni <xni@redhat.com> wrote:

> 
> 
> ----- Original Message -----
> > From: "NeilBrown" <neilb@suse.de>
> > To: "Xiao Ni" <xni@redhat.com>
> > Cc: linux-raid@vger.kernel.org, "Jes Sorensen" <jes.sorensen@redhat.com>
> > Sent: Wednesday, August 6, 2014 2:44:20 PM
> > Subject: Re: One patch just review the code
> > 
> > On Tue, 5 Aug 2014 03:12:07 -0400 (EDT) Xiao Ni <xni@redhat.com> wrote:
> > 
> > > Hi all
> > > 
> > >    I'm reading the code of md. I find there is a problem. I know now there
> > >    are arrays mark[SYNC_MARKS] mark_cnt[SYNC_MARKS]
> > > store the information about how many sectors finish recovery and the
> > > moment.
> > > 
> > > 
> > > 7825       currspeed = ((unsigned
> > > long)(io_sectors-mddev->resync_mark_cnt))/2
> > > 7826          /((jiffies-mddev->resync_mark)/HZ +1) +1;
> > >   
> > >    But when calculate the speed of recovery, the sectors used to calculate
> > >    contains
> > > the sectors which are not finished recovery.
> > > 
> > >    When assign value to mark_cnt[next], it subtract the sectors which don't
> > >    finish recovery.
> > > So I think when calculate the recovery speed we should subtract the sectors
> > > not finishing
> > > recovery too.
> > > 
> > > 7638          mark_cnt[next] = io_sectors -
> > > atomic_read(&mddev->recovery_active);
> > > 
> > >    So I try to modify and the patch is:
> > > 
> > > --- linux-stable/drivers/md/md.c 2014-07-30 14:36:37.327535805 +0800
> > > +++ fix/md.c   2014-07-31 16:40:57.151493177 +0800
> > > @@ -7652,7 +7652,7 @@
> > >        */
> > >       cond_resched();
> > >  
> > > -     currspeed = ((unsigned long)(io_sectors-mddev->resync_mark_cnt))/2
> > > +     currspeed = ((unsigned
> > > long)(io_sectors-atomic_read(&mddev->recovery_active)-mddev->resync_mark_cnt))/2
> > >          /((jiffies-mddev->resync_mark)/HZ +1) +1;
> > >  
> > >       if (currspeed > speed_min(mddev)) {
> > > 
> > >    Am I right?
> > 
> > Yes, that looks right.
> > If you create a properly formatted patch, and wrap that long line nicely I'll
> > apply it.
> > 
> > Thanks,
> > NeilBrown
> > 
> 
> I definite a new variable, do you allow me to do by this way?

Certainly, nothing wrong with a new variable.

But when you post a patch, please create a new email message with a short
description of the patch as the subject, any extra details or explanation in
the body, then the signed-off-by line and the patch. Then I can just apply
that email without editing it.

Thanks,
NeilBrown

> 
> Signed-off-by: Xiao Ni <xni@redhat.com>
> 
> diff -urN linux-stable/drivers/md/md.c fix/md.c
> --- linux-stable/drivers/md/md.c 2014-07-30 14:36:37.327535805 +0800
> +++ fix/md.c   2014-08-07 16:07:12.559503942 +0800
> @@ -7376,7 +7376,7 @@
>    struct mddev *mddev2;
>    unsigned int currspeed = 0,
>        window;
> -  sector_t max_sectors,j, io_sectors;
> +  sector_t max_sectors,j, io_sectors, recovery_done;
>    unsigned long mark[SYNC_MARKS];
>    unsigned long update_time;
>    sector_t mark_cnt[SYNC_MARKS];
> @@ -7652,7 +7652,8 @@
>        */  
>       cond_resched();
>  
> -     currspeed = ((unsigned long)(io_sectors-mddev->resync_mark_cnt))/2
> +     recovery_done = io_sectors - atomic_read(&mddev->recovery_active);
> +     currspeed = ((unsigned long)recovery_done - mddev->resync_mark_cnt)/2 
>          /((jiffies-mddev->resync_mark)/HZ +1) +1; 
>  
>       if (currspeed > speed_min(mddev)) {


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