Re: [PATCH 1/3] nilfs2: remove nilfs_segctor_init() in segment.c

[Li Hong <lihong.hi-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On Sun, Apr 11, 2010 at 02:57:15AM +0900, Ryusuke Konishi wrote:
> Hi,
> On Sun, 11 Apr 2010 00:15:43 +0800, Li Hong <lihong.hi-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > Hi KONISHI Ryusuke,
> > 
> > Three new patches based on nilfs2/for-next branch. New code has been built and
> > loaded successfully, and also passed a light-weight reads and writes test.
> > 
> > Thanks,
> > Li Hong
> 
> Ok, I'll look into each of them.
> 
> > ---------------------------- cut here --------------------------
> > 
> > From 2c622d0f59782321204bf1fde7eea4a593cc6b65 Mon Sep 17 00:00:00 2001
> > From: Li Hong <lihong.hi-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > Date: Sat, 10 Apr 2010 21:57:11 +0800
> > Subject: [PATCH 1/3] nilfs2: remove nilfs_segctor_init() in segment.c
> > 
> > There are only two lines of code in nilfs_segctor_init(). From a logic design
> > view, the first line 'sci->sc_seq_done = sci->sc_seq_request;' should be put in
> > nilfs_segctor_new(). Even in nilfs_segctor_new(), this initialization is
> > needless because sci is kzalloc-ed. So nilfs_segctor_init() is only a wrap call
> > to nilfs_segctor_start_thread(). This removes an indirect call overhead.
> > 
> > Signed-off-by: Li Hong <lihong.hi-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> 
> Looks no problem.
> 
> The reason why nilfs_segctor_init is present in that manner is
> historical (just for your information. You don't have to mention this
> reason).
> 
> I think you don't have to mention the indirect call overhead because
> it's only triggered in the level of mount/unmount/remount and gcc will
> inline it in the caller.
^^^^^^^^^^^^^^^^^^^^^^^^^
No, there is no inline key word in nilfs_segctor_init(). Unless you mean gcc
will try to inline small procedures if possible.

Thanks,
Li Hong

> Thanks,
> Ryusuke Konishi
> 
> > ---
> >  fs/nilfs2/segment.c |    9 +--------
> >  1 files changed, 1 insertions(+), 8 deletions(-)
> > 
> > diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
> > index f235fc0..514620d 100644
> > --- a/fs/nilfs2/segment.c
> > +++ b/fs/nilfs2/segment.c
> > @@ -2684,13 +2684,6 @@ static void nilfs_segctor_kill_thread(struct nilfs_sc_info *sci)
> >  	}
> >  }
> >  
> > -static int nilfs_segctor_init(struct nilfs_sc_info *sci)
> > -{
> > -	sci->sc_seq_done = sci->sc_seq_request;
> > -
> > -	return nilfs_segctor_start_thread(sci);
> > -}
> > -
> >  /*
> >   * Setup & clean-up functions
> >   */
> > @@ -2814,7 +2807,7 @@ int nilfs_attach_segment_constructor(struct nilfs_sb_info *sbi)
> >  		return -ENOMEM;
> >  
> >  	nilfs_attach_writer(nilfs, sbi);
> > -	err = nilfs_segctor_init(NILFS_SC(sbi));
> > +	err = nilfs_segctor_start_thread(NILFS_SC(sbi));
> >  	if (err) {
> >  		nilfs_detach_writer(nilfs, sbi);
> >  		kfree(sbi->s_sc_info);
> > -- 
> > 1.6.3.3
> > 
> > --
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