Subject: Re: kern/15364
To: None <chs@netbsd.org, gnats-admin@netbsd.org, netbsd-bugs@netbsd.org>
From: Chuck Silvers <chuq@chuq.com>
List: netbsd-bugs
Date: 08/29/2005 17:02:02
The following reply was made to PR kern/15364; it has been noted by GNATS.

From: Chuck Silvers <chuq@chuq.com>
To: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
Cc: gnats-bugs@NetBSD.org
Subject: Re: kern/15364
Date: Mon, 29 Aug 2005 10:01:34 -0700

 On Mon, Aug 29, 2005 at 09:18:36AM +0900, YAMAMOTO Takashi wrote:
 > > ah, it's the write clustering that's causing the problem.
 > > the attached patch forces the putpages write clustering to obey
 > > the same block-alignment rule that the getpages path uses, so that
 > > pages involved in a softdep dependency will always be written together.
 > > do you see any problem with this?
 > > 
 > > -Chuck
 > 
 > i don't think that block-alignment is really needed here.  (unlike lfs.)
 > isn't it better to have a bitmap in softdep "pcbp" to track which
 > pages in a block have been written out?
 
 well, I was thinking it would be good to have the property that a given block
 is written in one I/O, since that's what the softdep code was designed for,
 and it'd be safer to maintain the assumptions that the softdep code makes.
 but you're probably right that it's not really required.  would you like to
 implement your bitmap idea?
 
 -Chuck