From: Paul Clements <Paul.Clements@SteelEye.com>
To: ptb@it.uc3m.es
Cc: Neil Brown <neilb@cse.unsw.edu.au>, linux-raid@vger.kernel.org
Subject: Re: raid1 bitmap code [Was: Re: Questions answered by Neil Brown]
Date: Thu, 27 Feb 2003 02:26:00 -0500 [thread overview]
Message-ID: <3E5DBD88.2F0C8D87@SteelEye.com> (raw)
In-Reply-To: 200302262324.h1QNOu711769@oboe.it.uc3m.es
"Peter T. Breuer" wrote:
> Curiously enough, I'm slightly more nonplussed by the problem of
> kfreeing the bitmap pages when their dirty count drops to zero.
> I can foresee that when journalling we will go 0 1 0 1 0 1 in terms
> of number of bits dirty in the map, and if we kfree after the
> count drops to zero each time, and kmalloc when we should set
> the count to 1, then we will be held up. And maybe sleep when we
> shouldn't - the bitmap lock is held for some ops. Needs checking.
>
> What should I do? Maintain a how-many-times-we-have-wanted-to-free-this
> page count and only free it on the 10th attempt?
hmm...perhaps an LRU approach? you could store a timestamp (jiffies?),
so that you never deallocate a page unless it hasn't been used in X
amount of time...might be too heavyweight for what you're trying to do
--
Paul
next prev parent reply other threads:[~2003-02-27 7:26 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-02-24 20:15 Questions answered by Neil Brown Peter T. Breuer
2003-02-24 21:58 ` Paul Clements
2003-02-25 3:10 ` Neil Brown
2003-02-25 9:11 ` Peter T. Breuer
2003-02-26 7:44 ` Paul Clements
2003-02-26 8:09 ` Peter T. Breuer
2003-02-26 16:41 ` Paul Clements
2003-02-26 17:26 ` Peter T. Breuer
2003-02-26 18:29 ` raid1 bitmap code [Was: Re: Questions answered by Neil Brown] Paul Clements
2003-02-26 19:15 ` Peter T. Breuer
2003-02-26 22:12 ` Neil Brown
2003-02-26 23:24 ` Peter T. Breuer
2003-02-27 7:26 ` Paul Clements [this message]
2003-02-27 8:48 ` Peter T. Breuer
2003-02-27 15:47 ` Paul Clements
2003-02-27 5:33 ` Paul Clements
2003-02-27 10:35 ` Peter T. Breuer
2003-02-27 10:50 ` Peter T. Breuer
2003-02-27 16:51 ` Paul Clements
2003-02-27 17:18 ` Peter T. Breuer
2003-02-28 15:25 ` Peter T. Breuer
2003-02-28 16:14 ` Paul Clements
2003-02-28 16:23 ` Peter T. Breuer
2003-02-26 21:45 ` Questions answered by Neil Brown Neil Brown
2003-02-26 21:41 ` Neil Brown
-- strict thread matches above, loose matches on Subject: below --
2003-03-01 12:36 raid1 bitmap code [Was: Re: Questions answered by Neil Brown] Peter T. Breuer
2003-03-13 18:49 Peter T. Breuer
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