From mboxrd@z Thu Jan  1 00:00:00 1970
From: "bmoon" <bo@anthologysolutions.com>
Subject: Re: How do we handle the same but uptodated data to disk cache?
Date: Tue, 27 May 2003 13:47:59 -0700
Sender: linux-raid-owner@vger.kernel.org
Message-ID: <007c01c32491$43cf41e0$6b01a8c0@bmoon>
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To: Neil Brown <neilb@cse.unsw.edu.au>
Cc: linux-raid@vger.kernel.org
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Neil,

It improved a lot for the sync I/O.
However, I am looking for a solution to handle
the regular async I/O with a page data on the
same sector repeatedly like writing the MD SB
data to disk without flushing.

The follwing is my simple algorithm for it;

        bh=getblk(dev, block, size);
        if (buffer_uptodate(bh)) { /* still in cache, not flushed yet */
              bh->b_data = "updated data";
              brelse(bh);
        }
        else { /* all were flushed or new  */
            .
            .
             mark_buffer_uptodate(bh,1);
             mark_buffer_dirty(bh);
            generic_make_request(rw, &bh);
       }

 Please give me your suggestion or comment.


Bo
----- Original Message -----
From: "Neil Brown" <neilb@cse.unsw.edu.au>
To: "bmoon" <bo@anthologysolutions.com>
Cc: <linux-raid@vger.kernel.org>
Sent: Monday, May 26, 2003 7:47 PM
Subject: Re: How do we handle the same but uptodated data to disk cache?


> On Monday May 26, bo@anthologysolutions.com wrote:
> > Hello,
> >
> > I want to write the data to the fixed sector with the same size
frequently
> > just like MD super block, but I do not want to sync and flush the dev
> > on each write.
> >
> > For example, to write md super block in /drivers/md/md.c
>
> I suggest you look at a newer md.c.  With 2.4.21pre or 2.5.* have
> "sync_page_io" which does what you want more effectively.
>
> NeilBrown
>